Grout Calculator UK & Metric — kg/m² Coverage by Brand

British tiles are specified in millimetres and grout is bought by the kilogram, yet most online tools force you through inches and square feet. This UK & metric grout calculator works the way a UK tiler actually measures: tile size in mm, joint width in mm, joint depth equal to the tile thickness, area in square metres — and it returns kilogrammes per square metre, total kilos, and how many 2.5, 5, 10 or 20 kg bags belong in the trolley.

Every figure on this page comes from one formula — the same one UK technical datasheets are built on — so BAL, Dunlop, Weber, Palace, Norcros, Ultra Tile, Kerakoll and Litokol can be compared on identical terms. This page owns the metric market; the grout calculator on the homepage is its imperial, square-foot sibling.

It is built for the questions UK tilers actually type: how much grout per m² for 600 × 600 tiles, how many kilograms a 20 m² wall will drink, which bag size a BAL or Dunlop aisle should put in your basket, and what to do differently when the tub says Kerakoll or Litokol instead of a cement grout. Every answer shows its working — no black boxes, no chart transcription errors, no inches smuggled in through the back door.

UK & Metric Grout Calculator

mm in → kg/m² and bags out

Tile presets (mm)

Tile length (mm)

Tile width (mm)

Joint width (mm)

Joint depth (mm) — usually the tile thickness

Job size: 20 m² (215 ft²)

1 m²100 m²

Bag size

Coverage & buy

0.128kg/m² of mixed grout

Total

2.56

kg for 20 m²

Bags

× 5 kg, rounded up

Imperial

0.026

lb/ft² equivalent

+10% margin: 2.82 kg → 1 × 5 kg bag. The margin covers mixed-but-unused grout, deep beds and the half-bag that dries out between rooms.

How this answer is built

kg/m² = (A + B) ÷ (A × B) × J × D × 1.6

Right now: (600 + 600) ÷ (600 × 600) × 3 × 8 × 1.6 = 0.128 kg/m². Joint depth equals the tile thickness — grout fills the joint down to the bed, no further.

Anchors this page reproduces exactly: 600 × 600 at 3 × 8 mm → 0.128 kg/m²; 140 × 140 at 3 × 8 mm → 0.549 kg/m²; 200 × 100 brick at 2 × 6 mm → 0.288 kg/m².

Independent estimator — not affiliated with BAL, Dunlop, Weber, Palace, Norcros, Ultra Tile, Kerakoll or Litokol. Brand rows below describe typical product families and packaging; verify every figure against the bag and data sheet you actually buy.

The math

The kg/m² formula, in one line

Grout consumption is not a mystery and it is not brand secret knowledge. It is one line of arithmetic that converts the geometry of your tiling into the weight of mixed grout a square metre will drink. Learn the symbols once and every coverage chart on a UK data sheet becomes readable.

kg/m² = (A + B) ÷ (A × B) × J × D × 1.6

The symbols, in plain English

A — tile length in millimetres (600 for a 600 × 600 floor tile).
B — tile width in millimetres (100 for a 200 × 100 wall brick).
J — joint width in millimetres, the gap your spacers hold open.
D — joint depth in millimetres, which equals the tile thickness: grout fills the joint down to the adhesive bed.
1.6 — the fresh-density convention, kilograms per litre of mixed cement grout.

Where the 1.6 comes from

UK technical datasheets — BAL, Weber, Dunlop, Norcros and the rest — publish coverage charts built on a fresh-mixed density of about 1.6 kg per litre of cement grout. Some products quote 1.5, some 1.8; the calculator above lets you adjust it under Advanced when your data sheet disagrees.

Why the density barely matters: the geometry term (A + B) ÷ (A × B) × J × D swings from 0.08 litres/m² on a 600 × 600 floor to well over 1.4 litres/m² on mosaic sheet — a 17-fold range — while real densities cluster within ±10% of 1.6. Geometry sets the bill; chemistry only signs it.

One rule keeps this honest: every input stays in millimetres. The formula is unit-locked — feed it centimetres or inches and the answer drifts by orders of magnitude. If you catch yourself converting, stop and use the calculator at the top instead; it does the metric bookkeeping for you.

What the formula assumes — and what it does not

Every line of arithmetic carries fine print, and this one is no exception. It assumes a rectangular grid of identical tiles with joints of constant width — the everyday case for UK floors and walls. It counts each tile's perimeter joints once, treating the cross where four tiles meet as shared, which is the same convention the printed coverage charts use; the result errs very slightly on the generous side, which is the correct direction for a shopping list. It assumes the joint is fully filled to depth D — no raking out, no hollow beds behind the tile quietly drinking grout of their own.

It also ignores cuts. An edge course of quarter tiles adds joint length without adding area, so rooms with heavy cutting run a little over — one of the reasons the 10% margin exists. And it returns the weight of mixed grout the joints hold: the density term is what reconciles joint volume with the kilos on the bag. If your data sheet prints powder weights per square metre instead, the two agree within the density band, because the geometry term is identical either way. What the formula will never do is account for grout lost to a dirty bucket, a phone call that runs long, or the half-mix that goes off in the sun — that is what margins are for.

Show the working

How much grout per m²? Three worked examples

Three geometries cover most UK jobs: the large-format floor, the small-format floor, and the brick-bonded wall. Each card below shows every arithmetic step, so you can substitute your own numbers without trusting anyone's black box — including ours.

Verified anchor

A — 600 × 600 floor, 3 mm × 8 mm

The modern porcelain default. Big tiles are grout-cheap.

(600 + 600) = 1,200
600 × 600 = 360,000
1,200 ÷ 360,000 = 0.003333
× 3 (joint) = 0.01
× 8 (depth) = 0.08
× 1.6 = 0.128 kg/m²

A 20 m² floor needs 20 × 0.128 ≈ 2.6 kg — one 5 kg bag with more than half left over. At this geometry a 10 kg bag legitimately covers about 78 m².

The classic figure

B — 140 × 140 small-format, 3 mm × 8 mm

The textbook number quoted across UK small-format jobs.

(140 + 140) = 280
140 × 140 = 19,600
280 ÷ 19,600 = 0.014286
× 3 (joint) = 0.042857
× 8 (depth) = 0.342857
× 1.6 = 0.549 kg/m²

Round to 0.55 kg/m² — the classic small-format figure. The same 20 m² floor now drinks ≈ 11 kg: one 10 kg bag falls just short, so buy two 10 kg or one 20 kg. Quarter the tile, quadruple the grout.

Verified anchor

C — 200 × 100 wall brick, 2 mm × 6 mm

Slim joints, thin tile: the modest take of UK wall work.

(200 + 100) = 300
200 × 100 = 20,000
300 ÷ 20,000 = 0.015
× 2 (joint) = 0.03
× 6 (depth) = 0.18
× 1.6 = 0.288 kg/m²

A 20 m² wall consumes 20 × 0.288 ≈ 5.8 kg — one 10 kg bag. Note how the thinner 6 mm joint depth pulls take down even against the mid-size format.

Compare A and B and the lesson lands: tile size is the biggest lever on your bill, bigger than any brand choice. The geometry term (A + B) ÷ (A × B) is, to a close approximation, the total length of grout line packed into a square metre — and halving the tile size roughly doubles that length. Whatever sits between your tiles, measure the tile first and the bag size chooses itself.

The preset ladder: kg/m² at 3 mm × 8 mm for every calculator preset

The six presets in the calculator, evaluated at the standard 3 mm joints and 8 mm depth, form a ladder you can read at a glance. Run down it and the pattern is unmistakable: each step toward smaller tiles roughly adds half again to the take, and the ladder ends more than six times above where it starts.

Tile preset (mm)	kg/m² at 3 mm × 8 mm	20 m² job
100 × 100	0.768	15.4 kg
148 × 148	0.519	10.4 kg
200 × 200	0.384	7.7 kg
300 × 300	0.256	5.1 kg
300 × 600	0.192	3.8 kg
600 × 600	0.128	2.6 kg

Two anchors from this ladder deserve memorising. The bottom rung — 600 × 600 at 0.128 kg/m², a 20 m² floor for the price of one 5 kg bag — is the modern large-format floor at its most economical. The second rung — 148 × 148 at 0.519, trending toward the classic 0.55 kg/m² small-format figure — is where Victorian reproductions and quarry-style tiles live. If your job sits between rungs, the calculator interpolates exactly: the formula has no steps, only a smooth slope from grout-cheap to grout-hungry.

Decision tree

Which product is on your shelf? The UK brand row map

You do not need a different calculator for every brand — you need the right row of this page. Pick the branch that matches what is actually in your trolley and jump straight there. Every card below is one click from answer to section.

Start here

Metric tiles measured in mm

The calculator at the top of this page. Enter length, width, joint width, joint depth and area — kg/m² and bag count update instantly.

Go to section

Top route

A brand name on the bag

The UK brand coverage rows below. BAL, Dunlop, Weber, Palace, Norcros, Ultra Tile, Kerakoll and Litokol with typical UK bag sizes.

Go to section

Wet room

Epoxy grout in a wet room or pool

Kerakoll / Litokol epoxy rows, then the epoxy kit page. Epoxy is sold as mixed litres, not powder kilograms — the conversion changes.

Go to section Open the epoxy grout calculator

12 mm+

Wide joints of 12 mm and over

The wide-joint rows and the ×4 take warning. Wide-joint families exist for a reason: take per square metre climbs steeply past 12 mm.

Go to section

Not sure which branch you are on? If the tub mixes with water it is a cement grout and the bag math on this page applies; if it comes as two parts you stir together, it is epoxy and the third branch is yours. Mosaic sheets, penny rounds and glass faces are still metric — the mosaic tile grout calculator carries their sheet-gap arithmetic in mm.

The shelf

UK brand coverage rows

Here is the comparison the whole page exists for. The two kg/m² columns are formula-derived, not product claims — every row is evaluated at the same geometry, once at 300 × 300 and once at 600 × 600, both with 3 mm joints and 8 mm depth. That isolation is the point: read down a column and you see that a kilogram of BAL does the same work as a kilogram of Norcros at identical joints. What actually differs between the shelves is packaging — bag sizes, family naming, and which joint ranges each product family is built for. Framed as typical families and bag sizes — always verify on the pack and the data sheet before you buy.

Brand	Typical product family	Typical UK bag size — always verify on the pack	Joint width range per family	kg/m² @ 300×300, 3 mm × 8 mm	kg/m² @ 600×600, 3 mm × 8 mm
BAL	BAL Grout (fine, walls & floors) · BAL Max Flex (flexible) · BAL Wide Joint (wide joints)	10 kg	Grout 1–6 mm; Max Flex and Wide Joint 3–20 mm	0.256	0.128
Dunlop	Fine-joint wall & floor grouts, flexible grouts, wide-joint grouts	3–10 kg	Fine families ~1–5 mm; flexible and wide-joint families to 12–20 mm	0.256	0.128
Weber	Cement grout families from fine-joint wall grouts to wide-joint floor grades	5 kg	Fine 1–6 mm; wide-joint families to 20 mm	0.256	0.128
Palace Chemicals	Cement wall & floor grouts, flexible grouts, wide-joint grouts	Varies — check the pack	Fine 1–6 mm; wide-joint families to 20 mm	0.256	0.128
Norcros	Fine-joint and flexible cement grouts plus wide-joint grades	10 kg	Fine 1–6 mm; wide-joint grades to 20 mm	0.256	0.128
Ultra Tile	Fine-joint cement grouts with flexible and wide-joint variants	10 kg	Fine 1–6 mm; wide-joint variants to 20 mm	0.256	0.128
Kerakoll	Fugabella Color (cement) · Fugalite (epoxy, sold as kits)	Fugabella 5 kg; Fugalite by kit volume	Fugabella fine to wide per family; Fugalite per data sheet	0.256	0.128
Litokol	Starlike EVO (epoxy, sold as kits) · Flowpoint (self-smoothing cement)	Starlike 2.5–5 kg; Flowpoint 25 kg sack	Starlike 0–20 mm; Flowpoint per pack	0.256	0.128

A word on why the numbers repeat down the columns. Brand chemistry shifts the fresh density a little — 1.5 to 1.8 kg/L across the market — but the geometry term dominates the arithmetic, so at the same tile and joints every cement grout lands within a few percent of its neighbours. Choose between brands on flexibility, colour range, water resistance and bag economics, not on coverage: coverage is a property of your tiling, not their tub.

Reading a row against a real data sheet

Take any row and test it against the paper copy in your hand — the exercise takes two minutes and settles every argument. First, find the coverage or yield table on the data sheet, usually printed as square metres per kilogram at a reference tile and joint. Divide 1 by that printed figure and you have the brand's own kg/m²; compare it against this page's formula at the same geometry. Agreement within about 10% is normal. A bigger gap means one of three things, and they are worth checking in order: the joint depth the chart assumed (many UK charts print at the tile thickness, but not all), the mixed density the brand applies, and whether the chart already includes a waste allowance.

Second, match the product to the joint range column, not the brand name. A fine-joint grout rated for 1–6 mm is not interchangeable with the wide-joint family wearing the same logo, and neither slumps less for being expensive. Third, treat the bag-size column as a pricing unit, not a ranking: coverage per bag follows your geometry, as the BAL question in the FAQ below demonstrates. The pack and the data sheet remain the final word — this table tells you which shelf section to walk to, and the formula tells you how many steps of it to buy.

The Kerakoll / Litokol epoxy exception

Kerakoll Fugalite and Litokol Starlike EVO are epoxies, and epoxies break the bag habit: they are sold as two-part kits by mixed volume in litres, not as kilograms of powder. The joint geometry term is identical, but the conversion is joint litres ÷ kit litres — the kg/m² columns above do not apply to them. The epoxy grout calculator does that kit math properly. Litokol Flowpoint is the exception on the exception: a self-smoothing cement grout that does arrive in a 25 kg sack, so bag math applies — at its own density, which the pack states.

Wide joints: 12 mm and over

The table's joint-width column matters most here. At 12 mm joints the 600 × 600 tile recomputes to (1,200 ÷ 360,000) × 12 × 8 × 1.6 = 0.512 kg/m² — four times the 3 mm figure. At 20 mm joints it reaches 0.853 kg/m², and small formats go further still. This is exactly why BAL Max Flex, BAL Wide Joint, the wide-joint families from Dunlop, Weber, Palace, Norcros and Ultra Tile, and Litokol Flowpoint exist: a fine-joint grout pushed past its rated range slumps, cracks and costs you the floor. Above roughly 12 mm, buy the wide-joint family and re-run the calculator with your real joint width.

Packaging

Bags, pallets and the UK shelf

The UK grout shelf sorts into four weights, and knowing them turns a kg/m² figure into a shopping list. 2.5 kg tubs suit feature walls, splashbacks and mosaic sheets, where a little colour goes a long way. 5 kg bags are the bathroom-size unit — one room, one bag, no leftovers going stale in the shed. 10 kg is the UK default: BAL, Norcros and Ultra Tile all anchor their ranges there, and most kitchens land on one or two. 20 kg sacks are site territory, matching the Flowpoint class of self-smoothing grout for big floors. Whatever the size, buy every bag for a room from the same batch — colour drift between batches shows as a faint patchwork across the joints — and keep the bags sealed until the moment you mix.

Worked bag plan: a 20 m² kitchen floor

600 × 600 tiles, 3 mm joints, 8 mm deep
take = 0.128 kg/m²
20 m² × 0.128 = 2.56 kg ≈ 2.6 kg
margin: 2.56 × 1.1 = 2.8 kg
buy: 1 × 5 kg bag (≈ 2.4 kg spare)

The spare is not waste — it is insurance against grout take surprises (the warning card below explains where they come from) and against the one tile you cut wrong twice. If the same kitchen were 140 × 140 mosaic on the floor, the plan would read 20 × 0.549 ≈ 11 kg: one 10 kg bag short, so two 10 kg bags. Same room, same tiler, four times the grout.

The kg ↔ lb bridge

1 kg/m² ≈ 0.205 lb/ft²
1 kg ≈ 2.2 lb · 1 m² = 10.76 ft²

Metric and imperial coverage are the same fact in two dialects. The page anchors translate as: 0.128 kg/m² → 0.026 lb/ft², 0.288 kg/m² → 0.059 lb/ft², 0.549 kg/m² → 0.113 lb/ft². If you straddle both markets, remember that a pound is heavier than it feels and a square foot is smaller than a tenth of a square metre — the two corrections nearly cancel, which is why 0.205 is safe mental arithmetic.

The imperial siblings of this page are the ARDEX grout calculator and the Davco grout calculator — both work in square feet and pounds for US-style projects.

Inverting the chart: from bag yield to your job

Data sheets print coverage forward — square metres per bag at a reference geometry. Your job runs backward, and the inversion is a single division. Take the printed yield, divide 1 by it to reach kg/m², multiply by your area, and you have your total. A 10 kg bag printed at 39 m² is telling you 1 ÷ 39 = 0.128 kg/m² — the 600 × 600 anchor again, now recognised on sight. The scaling is exact for the stated geometry, and because the formula is linear in joint width and depth separately, neighbouring geometries convert by simple ratio.

One worked inversion closes the loop. Suppose the chart quotes that same 10 kg bag at 39 m² for 3 mm joints, but your spacers are 5 mm. The take scales by 5 ÷ 3: 0.128 × 5/3 = 0.213 kg/m², so the same bag now covers 10 ÷ 0.213 ≈ 47 m² of your floor. Depth converts by the same ratio — doubling the joint depth doubles the take. One division, one multiplication, and any coverage chart printed anywhere in the UK becomes your personal estimate, whatever the tile in your hallway actually is.

Tip: weigh what you mix

Trust the scale, not the scoop — and never the bag label once it is open. A half-used bag loses moisture over weeks in the shed, so the "10 kg" printed on it quietly becomes 9 kg of powder with water-starved chemistry. Weigh the powder for each mix, log what each room consumed, and your kg/m² figure becomes a real site number instead of a guess.

Warning: deeper joints inflate take

This calculator assumes joint depth equals tile thickness. If joints were raked out, or the tiler back-butters generously and leaves voids behind the tile, grout fills that hidden volume and take can double against the printed figure. On raked or deep-joint work, measure the actual depth and enter it — the formula is honest as long as you are.

Don't: feed mm tiles to an imperial tool

Don't type 600 mm tiles into a square-foot calculator. One square metre is 10.76 ft², so unit drift scales every answer by ×10.76 — you would buy a pallet for a bathroom. Metric tiles, metric tool: this page for millimetres, the homepage grout calculator for inches and square feet.

UK bathroom with large-format wall tiles and a metric tape measure resting across fresh grout lines

Millimetres on the tape, kilograms on the bag — the whole UK workflow in one line of arithmeticPhoto: Unsplash

UK grout FAQ — kilos, bags and brands

Top questionHow much grout per m² for 600×600 tiles?

At the UK standard floor setup — 3 mm joints, 8 mm deep — the formula gives (600 + 600) ÷ (600 × 600) × 3 × 8 × 1.6 = 0.128 kg/m². That is roughly one kilogram of mixed grout for every 7.8 m² of tile, so a 20 m² kitchen floor consumes about 2.6 kg and a single 5 kg bag covers it with margin. Widen the joints to 6 mm and the figure doubles to 0.256 kg/m²; at 12 mm joints it reaches 0.512 kg/m². The joint width, not the tile brand, drives the answer.

What is the formula for grout consumption calculation for tiles?

kg/m² = (A + B) ÷ (A × B) × J × D × 1.6, where A is tile length in mm, B is tile width in mm, J is joint width in mm, D is joint depth in mm, and 1.6 is the fresh density of mixed cement grout in kg/L. The term (A + B) ÷ (A × B) counts how many metres of grout line cross each square metre of tiling; multiplying by the joint cross-section (J × D) turns that into litres, and the density converts litres to kilograms. Keep every measurement in millimetres — the result is only valid in metric units.

How much grout per m² calculator — what do I enter?

Five numbers, all metric. First the tile length and width in millimetres — pick a preset such as 600 × 600 or type your own. Second, the joint width your spacers set (2–10 mm here). Third, the joint depth, which equals the tile thickness: 6, 8, 10 or 12 mm. Fourth, the job area in square metres on the slider. Open the advanced control only if your datasheet quotes a mixed density other than 1.6 kg/L. The calculator returns kg/m², total kilograms, the bag count at your chosen 2.5, 5, 10 or 20 kg size, and the lb/ft² equivalent.

Which BAL grout covers the most per bag?

The bag does not decide coverage — the tiles do. A 10 kg bag of any BAL cement grout spreads across 10 ÷ 0.128 ≈ 78 m² of 600 × 600 tile at 3 mm × 8 mm joints, yet the same 10 kg covers barely 18 m² of 140 × 140 tile at 0.549 kg/m². Within the range, BAL Grout and BAL Max Flex share fine-joint geometry, while BAL Wide Joint exists for 3–20 mm lines where take per square metre climbs steeply. Buy for the joint geometry of your job, and verify the printed coverage row on the pack before committing.

How many kg of grout for 20 m² of wall tile?

For the classic 200 × 100 mm wall brick at 2 mm joints and 6 mm depth, take is 0.288 kg/m², so 20 m² needs 20 × 0.288 ≈ 5.8 kg — one 10 kg bag with room to spare, or two 5 kg bags. Move to 300 × 600 wall tiles at 3 mm joints and 8 mm depth and the same wall consumes only 20 × 0.256 ≈ 5.1 kg. If the wall is small-format 140 × 140 tile at 3 mm joints, budget closer to 11 kg. Measure the actual tile and joints, then let the formula — not habit — set the bag count.

Is there a Weber or Dunlop grout calculator that differs from this?

No manufacturer publishes arithmetic that contradicts the kg/m² formula — Weber, Dunlop and BAL coverage charts are built from the same joint-geometry calculation with a mixed density close to 1.6 kg/L. Where branded tools differ is packaging: bag sizes (Dunlop spans 3–10 kg, Weber typically sells 5 kg), rounding rules and the safety margin each brand adds. Treat any brand chart as this page's formula plus that brand's bag rounding. If a brand tool returns a figure wildly different from yours, check two things first: which units it assumed, and whether it counted joint depth as the tile thickness.

How much does Kerakoll Fugalite or Litokol Starlike epoxy cover?

Epoxy does not convert through bag weight the way cement grout does — Fugalite and Starlike are two-part kits measured in litres of mixed material. The joint volume is the same geometry term every calculator uses; the conversion is joint litres ÷ kit litres, rounded up to whole kits. Starlike EVO joints run from 0 to 20 mm depending on the version, so check the version on the tub before you plan. A worked anchor: 10 m² of 300 × 300 tile at 3 mm × 8 mm holds 1.6 L of joint — the epoxy grout calculator turns that figure into kit counts for the product on your shelf.

What is grout take and why does it differ from bag yield?

Grout take is the weight of mixed grout actually consumed per square metre on your job — what the empty tubs on site prove. Bag yield is the theoretical figure printed from the formula under laboratory conditions. The two drift apart for physical reasons: joints raked deeper than the tile thickness hold more grout than the calculator assumed, dry substrates pull water out of the mix, half-used bags have already lost moisture, and bedding voids behind the tile quietly fill with grout. Plan on the formula, add a 10% margin, then weigh your first mixed bag against the area it covered to find your true take.

Where to next

This page is the metric outpost of a wider toolkit. If your project quotes inches, runs through US brand packaging, or involves joints that this page's rectangular-tile formula does not model — penny rounds and hex mosaics among them — these are the doors to knock on.

The imperial home base

The grout calculator on the homepage is the sq-ft home base of this site: inches and pounds, sized for US packaging and imperial plans. Metric tiles in, metric tool; imperial plans, imperial tool — that division of labour is deliberate.

Open the main grout calculator

The full calculator hub

Cost planning, sealer volumes, joint-width guides, wall-floor-shower presets and more live on the calculators hub — one page, every tool, each with the same worked-example treatment you just read here.

Browse all calculators

One more metric corner case: mosaic sheets, penny rounds and hex tiles are still measured in millimetres, but their mesh gaps add grout area the rectangular formula never sees. For those, use the mosaic tile grout calculator — mosaics in mm, with sheet-gap share and waste presets built in.