How much grout for 100 sq ft of 12x24 tile?
2.9 kg of grout for a 100 sq ft of 12x24 tile, at the settings most people start with. Below the calculator are the same numbers for the alternatives you are likely to choose, and what each one does to the total.
Reviewed · Method: measured dimensions, industry coverage rates, rounded up to real package sizes · How the numbers are calculated
Values are pre-filled for this page. Change anything and hit Recalculate.
The answer, and what it is made of
100 sq ft of 12 x 24 tile with a 3 mm joint at 8 mm deep needs 2.9 kg of grout — one of the 10 kg bag. Buy the full bag even if you only need part of it: opened grout takes up moisture from the air and sets lumpy within weeks.
Planning figure for everything on that list: $19 to $45, with $29 as the realistic middle for the products most people actually buy. These are estimates for budgeting, not quotes. Prices move by region and by season, and the middle figure assumes a mid-range product rather than the cheapest thing on the shelf.
Joint width does most of the work here: 3.3 kg at a 1/8 in joint joint becomes 2.2 kg at 1/16 in joint. The joint is a volume, not a line, so doubling its width roughly doubles the grout for the same floor.
What changes if you change one thing
| Change the joint width | You buy |
|---|---|
| 1/8 in joint, 3/8 in deep | 3.3 kg |
| 3/16 in joint, 3/8 in deep | 5.4 kg |
| 1/16 in joint, 3/8 in deep | 2.2 kg |
Every row is a live calculation, not an estimate. The shaded row is what this page defaults to.
What goes in the cart
| Item | Quantity |
|---|---|
| Grout, 10 kg bag | 1 bag |
| Grout float (rubber face) | 1 |
| Grout sponge, large pore | 2 |
| Sealer, 1 qt (for porous grout) | 1 qt |
| Bucket + mixing paddle | 1 set |
Do not mix the whole bag. Mixed grout has a 20 to 30 minute pot life. Mix in batches sized to what you can float and wipe in that window, or you will be scraping rock out of the joints.
What this size actually changes
One hundred square feet of 12x24 with a 3 mm joint is about 62 linear feet of joint, which is a low joint density — only 0.3 kg per square metre. That is why large format tile uses so much less grout than the bag suggests: the joint length per square foot falls as the tile gets bigger, and grout quantity follows joint length, not floor area.
Figure. 100 sq ft of 12x24 tile: 10 x 10 ft. Measure the finished surface, not the room walls — the area between skirting or cabinet faces is the area you pay for.
How the quantity is worked out
Grout quantity is driven by the joint, not the floor. Two jobs with the same square footage can need three times the grout if one uses a 1/4 in joint and the other a 1/16 in joint, because the volume of the gap scales with joint width and depth together. That is why grout bags carry a yield chart instead of a single coverage number.
Depth matters as much as width. A 3/8 in deep joint takes twice the grout of a 3/16 in joint at the same width. On a floor with a deep bed, you are filling a channel, not wiping a line. Cementitious grout also shrinks slightly as it cures, so the joint you fill is not quite the joint you end up with.
How to measure this job
Measure the floor at its widest point in both directions, then measure again between the skirting and the vanity, because the tiled area is what you pay for and the fixtures are not floor. A 12x12 ft bathroom rarely has 144 sq ft of open floor: a tub, a vanity and a toilet occupy somewhere between 20 and 30 sq ft, but they still need tile under and around them. Do not subtract them.
The toilet is the exception worth planning for. The flange, the supply line and the base of the toilet all interrupt the tile field, and the cuts around them are slow and error-prone. That is why a bathroom needs the higher end of the waste allowance even when the layout looks simple.
Mistakes that cost real money
Buying grout by square footage instead of by joint volume
A 10 lb bag does not cover a fixed area. It covers a volume. Two floors of the same size can differ by a factor of three depending on joint width and depth, so the bag count has to come from the joint dimensions, never from the room size alone.
Tiling up to the toilet flange and stopping
The tile has to run under the toilet, with a neat cut around the flange. Tiling around the toilet base instead means the base sits on two different levels, which rocks, cracks the wax ring and leaks. Pull the toilet, tile, then reset it on a new ring.
Using a 1/4 in joint to hide uneven tiles
A wider joint does hide lippage, but on 12x24 it also triples the grout and makes the floor look like a 1980s shopping centre. Large format should be laid with a 1/8 in joint and a levelling system, not with a fat joint as a cover-up.
Mixing grout thinner than the bag says
On a large format floor the joint is shallow and wide, so people mix grout wet to make it flow. Wet grout shrinks more and leaves a low, dusty joint that collects dirt. Mix to the consistency of peanut butter and work it in with a hard float.
Frequently asked questions
How many square feet does a 10 lb bag of grout cover?
There is no single number, because it depends on tile size, joint width and joint depth. A 10 lb bag on 12x24 tile with a 1/8 in joint covers roughly 100 sq ft. The same bag on 3x6 subway tile with the same joint covers far less, because the joint length per square foot is much higher.
Do I subtract the tub and vanity when calculating bathroom floor tile?
No. Tile runs under the vanity and up to the tub, and the visible area is smaller than the tiled area. Subtracting fixtures gives you a short order every time, and a short order on a bathroom means a second trip for a carton from a different dye lot.
How much grout for 100 sq ft of 12x24 tile?
About 2.9 kg with a 3 mm joint at 8 mm deep, so one 10 kg bag covers roughly 300 sq ft of this tile. At a 5 mm joint it rises to about 5 kg for the same 100 sq ft, which is why joint width, not floor area, drives the order.
Does grout colour have to match the tile?
No, but it changes the whole floor. A grout close to the tile colour makes 12x24 read as one surface; a contrasting grout draws a grid and makes the room look smaller. On large format, most people regret a contrasting grout within a year.
What will the materials for this cost?
A planning range of $19 to $45 for everything in the shopping list, with $29 as the realistic middle. That is materials only: it excludes labour, delivery, tool hire and disposal of the old surface. Treat it as a budgeting figure, not a quote.