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Grout chart
Put your area, coverage per bag and waste allowance in: 400 sq ft at 10% waste needs 8.80 bags exact, order 9.
★ CONSTRUCTION · GROUT · COVERAGE CHART
Grout Coverage Chart: 9 Bags for 400 Sq Ft at 10% Waste
On the defaults — 400 square feet at 10% waste with 50 square feet per bag coverage — you need 440.00 square feet of grout, 8.80 bags exact, so order 9 bags. This is the GROUT version — area times waste divided by coverage, with a lookup table for every common area and coverage — the paint-chart page is the PAINT version — the same divide-and-round-up model counted in topcoat gallons; the primer-chart page is the PRIMER version — the same model counted in primer gallons; the grout-coverage-chart page is the COVERAGE version — grout coverage figures on their own; and the tile-chart page is the TILE version — the same model counted in tiles.
What does 8.80 bags, order 9, mean?
It means that 400 square feet of surface, with a 10% waste allowance, need 440.00 square feet of grout, and at 50 square feet per bag that is 8.80 bags — eight full bags plus four fifths of a ninth — and because grout is sold by the bag, you order 9. The rounding is the whole story in miniature: a partial bag cannot be bought in the quantity needed, so any fraction, however small, becomes a whole bag. The part people get wrong is rounding to the nearest bag instead of up: 8.80 rounded to the nearest is 9 here, but the same mistake on an 8.20-bag job rounds to 8, and 8 bags cover only 400 square feet, leaving 40.00 square feet ungrouted. The other part people get wrong is the exact fit: 440 square feet of coverage need exactly 1.00 bag, and order exactly 1, because the rounding is up to the next whole bag, not up plus one — an exact fit needs no spare bag from the rounding, though a spare for touch-ups is a separate decision.
Three things to check before you trust the number
Is 50 square feet per bag right for your grout and joints? Fifty square feet per bag is a typical grout figure used on this page, and published grout coverage varies with product, tile size, joint width and joint depth. A wide or deep joint eats grout fast: the 100-square-feet branch needs 4.40 bags, order 5, for the same 400 square feet, so a higher-coverage grout halves the order — but on a larger job the coverage figure decides whole bags. Enter your own figure if your product differs, rather than trusting the default for a wide-jointed floor.
Did you measure every surface? The area entered here must be the total of all surfaces, not the largest single floor or wall: a bathroom with 400 square feet of floor plus walls has more than 400 square feet to grout. The 200-square-foot branch needs 4.40 bags, order 5, against the 8.80-bag headline, so missing one wall understates the order by whole bags on a bigger job. Measure every floor and wall area, add the surfaces before dividing, and do not subtract small fixtures unless your grout maker says to.
Are you counting waste, or a second pass? This page adds 10% for waste — mixing loss, spills and touch-ups — and that is not a second pass. A second pass doubles the area first: 400 square feet passed twice is 800 square feet before waste, which is 880.00 square feet with waste and 17.60 bags, order 18. Treating a second pass as waste, or waste as a second pass, misstates the order by whole bags either way, so decide the passes first and let the waste percentage stay at waste.
Worked example
On the defaults: 400 square feet, 50 square feet per bag, 10% waste.
- Needed area: 400 × 1.10 is 440.00 square feet.
- Exact bags: 440.00 ÷ 50 is 8.80 bags.
- Order: 8.80 rounded up is 9 bags — the 0.80 is four fifths of a bag that must be bought whole.
- Check: 9 bags cover 450 square feet, which is more than the 440.00 needed; 8 bags cover only 400, which is not enough.
And the other way: the area behind 8.80 bags is 400 square feet, the coverage behind 8.80 bags is 50 square feet per bag, and the waste behind 8.80 bags is 10%. A job at 440 square feet per bag orders exactly 1 bag, and the 800-square-foot, 25-square-feet-per-bag lookup row lands exactly on 35.20 bags, order 36.
Every branch, checked
- 200 square feet, 50 square feet per bag, 10% waste: 200 square feet, 50 square feet per bag, 10% waste: 4.40 bags exact — order 5 bags.
- 800 square feet, 50 square feet per bag, 10% waste: 800 square feet, 50 square feet per bag, 10% waste: 17.60 bags exact — order 18 bags.
- 400 square feet, 100 square feet per bag, 10% waste: 400 square feet, 100 square feet per bag, 10% waste: 4.40 bags exact — order 5 bags.
- 400 square feet, 50 square feet per bag, 20% waste: 400 square feet, 50 square feet per bag, 20% waste: 9.60 bags exact — order 10 bags.
The reverses, worked backwards
- Area behind 8.80 bags: 400 sq ft — at 400 sq ft the figures are 8.80 bags exact — order 9 bags.; at the lower neighbor the figures are 7.70 bags exact — order 8 bags.; at the upper neighbor the figures are 9.90 bags exact — order 10 bags..
- Coverage behind 8.80 bags: 50 sq ft per bag — at 50 sq ft per bag the figures are 8.80 bags exact — order 9 bags.; at the lower neighbor the figures are 11.00 bags exact — order 11 bags.; at the upper neighbor the figures are 7.33 bags exact — order 8 bags..
- Waste behind 8.80 bags: 10% waste — at 10% waste the figures are 8.80 bags exact — order 9 bags.; at the lower neighbor the figures are 8.40 bags exact — order 9 bags.; at the upper neighbor the figures are 9.20 bags exact — order 10 bags..
What the defaults assume
The defaults are 400 square feet, 50 square feet per bag and 10% waste, so the headline is one pass of a typical grout over a medium floor and wall run. The model is a multiplication, a division and a ceiling: needed area is area times one plus the waste percentage, exact bags are needed area divided by coverage per bag, and the order rounds exact bags up to the next whole bag, with a 1e-12 epsilon so an exact whole number orders exactly that many. The area reverse is checked at 50 square feet either side, because 50 square feet at 10% waste is 55 square feet, about 1.10 bags; the coverage reverse is checked at 10 square feet either side, because 440.00 over 40 is 11.00 bags and over 60 is 7.33; the waste reverse is checked at 5% either side, because 5% of 400 is 20 square feet, about 0.40 bags. The model does not include second passes, grout type differences beyond the coverage figure, joint size beyond the coverage figure, or tools — count those separately.
Lookup table: bags by area and coverage
Each row already includes the 10% waste allowance: needed area is the area times 1.10, exact bags are needed area divided by the coverage in that row, and the order column rounds up. A row that lands exactly on a whole number orders exactly that many — no extra bag is added for an exact fit. For a different grout, enter your own coverage in the calculator above: a lower-coverage grout covers fewer feet per bag, so the order rises.
| Area | Coverage per bag | Needed area | Exact bags | Order |
|---|---|---|---|---|
| 100 sq ft | 25 sq ft per bag | 110.00 sq ft | 4.40 | 5 bags |
| 100 sq ft | 50 sq ft per bag | 110.00 sq ft | 2.20 | 3 bags |
| 100 sq ft | 100 sq ft per bag | 110.00 sq ft | 1.10 | 2 bags |
| 100 sq ft | 200 sq ft per bag | 110.00 sq ft | 0.55 | 1 bags |
| 200 sq ft | 25 sq ft per bag | 220.00 sq ft | 8.80 | 9 bags |
| 200 sq ft | 50 sq ft per bag | 220.00 sq ft | 4.40 | 5 bags |
| 200 sq ft | 100 sq ft per bag | 220.00 sq ft | 2.20 | 3 bags |
| 200 sq ft | 200 sq ft per bag | 220.00 sq ft | 1.10 | 2 bags |
| 400 sq ft | 25 sq ft per bag | 440.00 sq ft | 17.60 | 18 bags |
| 400 sq ft | 50 sq ft per bag | 440.00 sq ft | 8.80 | 9 bags |
| 400 sq ft | 100 sq ft per bag | 440.00 sq ft | 4.40 | 5 bags |
| 400 sq ft | 200 sq ft per bag | 440.00 sq ft | 2.20 | 3 bags |
| 800 sq ft | 25 sq ft per bag | 880.00 sq ft | 35.20 | 36 bags |
| 800 sq ft | 50 sq ft per bag | 880.00 sq ft | 17.60 | 18 bags |
| 800 sq ft | 100 sq ft per bag | 880.00 sq ft | 8.80 | 9 bags |
| 800 sq ft | 200 sq ft per bag | 880.00 sq ft | 4.40 | 5 bags |
Output · formula · meaning
| Output | Formula | What it means |
|---|---|---|
| Needed area | area × (1 + waste ÷ 100) | 440.00 sq ft — 400 × 1.10. |
| Exact bags | needed area ÷ coverage per bag | 8.80 bags — 440.00 ÷ 50. |
| Order | exact bags rounded up | 9 bags — 8.80 rounds up. |
| Area behind a target exact figure | exact bags × coverage per bag ÷ (1 + waste ÷ 100) | 400 sq ft — 8.80 × 50 ÷ 1.10. |
| Coverage behind a target exact figure | needed area ÷ exact bags | 50 sq ft per bag — 440.00 ÷ 8.80. |
| Area covered by the order | order × coverage per bag | 450 sq ft — 9 × 50, more than the 440.00 needed. |
| Square feet short on one fewer bag | needed area − (order − 1) × coverage per bag | 40.00 sq ft — 440.00 − 8 × 50, which is why rounding down fails. |
| 200 square feet, 50 square feet per bag, 10% waste | same model | 4.40 bags exact — order 5 bags. |
| 800 square feet, 50 square feet per bag, 10% waste | same model | 17.60 bags exact — order 18 bags. |
| 400 square feet, 100 square feet per bag, 10% waste | same model | 4.40 bags exact — order 5 bags. |
| 400 square feet, 50 square feet per bag, 20% waste | same model | 9.60 bags exact — order 10 bags. |
| Area behind 8.80 bags | reverse | 400 sq ft: 8.80 bags exact — order 9 bags. |
| Coverage behind 8.80 bags | reverse | 50 sq ft per bag: 8.80 bags exact — order 9 bags. |
| Waste behind 8.80 bags | reverse | 10% waste: 8.80 bags exact — order 9 bags. |
| 0 square feet | same model | 0.00 bags exact — order 0 bags. |
| Negative area | same model | Area — 0 or more. |
| Zero coverage | same model | Coverage — more than 0. |
| 440 square feet per bag | same model | 1.00 bags exact — order 1 bags. |
Who uses this
- A DIYer grouting a bathroom — 400 square feet at 10% waste is 9 bags, with the lookup table covering every other area and coverage without re-measuring.
- A tiler ordering for a job — the branches show how the order moves with area, coverage and waste, so a wide-jointed floor is repriced before ordering.
- A homeowner comparing grouts — the 100-square-feet branch shows what a higher-coverage grout really saves in bags, before the job starts.
- An estimator checking a quote — the reverses recover the area, coverage or waste behind any quoted bag count, which checks a quote without re-measuring the job.
Accuracy & limitations
Figures are the model’s own arithmetic on the numbers you type, computed from unrounded values and displayed rounded HALF_UP to 2dp, with orders rounded up using a 1e-12 epsilon so exact fits are not over-ordered. The main limitation is the coverage figure, not the arithmetic: published grout coverage varies with product, tile size, joint width and joint depth, so check your product and enter your own figure when your joints differ. This page is a calculation tool, not trade advice — follow the grout maker’s instructions for mixing and application.
Cite this calculator
400 square feet at 10% waste with 50 square feet per bag coverage needs 440.00 square feet, 8.80 bags exact: order 9 bags. Source: Bright Side Kit, https://brightoolbox.com/grout-chart/, accessed 29 October 2026.
Frequently asked questions
How many square feet does one bag of grout cover?
This page uses 50 square feet per bag, a typical grout figure — but published grout coverage varies with product, tile size, joint width and joint depth. If your grout or joints differ, enter your own coverage figure: the calculator divides by whatever you enter, so the answer stays honest for your product.
Why add 10% waste?
Because grout is lost in mixing, spills happen and touch-ups need material: the 10% allowance covers the grout that never lands in the joints as intended. Without it, a job that computes to exactly 9.00 bags would run dry on the last stretch of joints, and the waste percentage is what keeps the order honest for real application.
Why round up instead of to the nearest bag?
Because a partial bag cannot be bought in the quantity needed, and rounding down leaves surface ungrouted: 8.80 bags rounded to the nearest happens to be 9 here, but an 8.20-bag job rounded to the nearest is 8, and 8 bags cover only 400 of the 440.00 square feet needed. Rounding up guarantees the whole area is covered; the extra fraction is the price of buying whole bags.
What if the exact figure is already a whole number?
Then you order exactly that many: a job at 440 square feet per bag needs exactly 1.00 bag and orders 1, not 2, and the epsilon in the rounding protects exact fits, so a job that lands on a whole number is not charged an extra bag for nothing.
Does the waste allowance cover a second pass?
No: waste and passes are different things. Waste is the extra 10% for mixing loss, spills and touch-ups on one pass; a second pass doubles the area first, so 400 square feet passed twice is 800 square feet before waste, which is 880.00 square feet with waste and 17.60 bags, order 18. Decide the passes first, then let waste stay at waste.
Should I buy a spare bag beyond the order?
That is a separate decision from the order column: the order column is the exact math for the measured area, and a spare covers thirsty joints, over-application and touch-ups. On wide or deep joints, one spare is cheap insurance; on a single smooth pass, it is usually unnecessary.