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Tile adhesive chart
Put your area, coverage per bag and waste allowance in: 400 sq ft at 10% waste needs 11.00 bags exact, order 11.
★ CONSTRUCTION · TILE · ADHESIVE CHART
Tile Adhesive Chart: 11 Bags for 400 Sq Ft at 10% Waste
On the defaults — 400 square feet at 10% waste with 40 square feet per bag coverage — you need 440.00 square feet of adhesive coverage, 11.00 bags exact, so order 11 bags. This is the TILE-ADHESIVE version — area times waste divided by coverage, with a lookup table for every common area and waste level — the grout-sealer-chart page is the GROUT-SEALER version — the same divide-and-round-up model counted in sealer bottles; the thinset-chart page is the THINSET version — the same model counted in thinset bags; the grout-chart page is the GROUT version — the same model counted in grout bags; and the mortar-chart page is the MORTAR version — the same model counted in mortar bags.
What does 11.00 bags, order 11, mean?
It means that 400 square feet of tile, with a 10% waste allowance, need 440.00 square feet of adhesive coverage, and at 40 square feet per bag that is exactly 11.00 bags — eleven full bags with nothing left over — so you order 11. The exact fit 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, but an exact whole number needs no extra bag at all. The part people get wrong is adding a spare bag to an exact fit out of habit: 11.00 bags already cover the full 440.00 square feet, and a twelfth bag is a separate decision about breakage, not something the rounding demands. The other part people get wrong is rounding to the nearest bag instead of up: 5.50 bags rounded to the nearest is 6 here by luck, but 5.40 rounded to the nearest is 5, and 5 bags cover only 200 square feet, leaving the rest of the floor without adhesive.
Three things to check before you trust the number
Is 40 square feet per bag right for your adhesive and trowel? Forty square feet is the figure this page uses, a mid-range figure for a standard bag at a common notch size. Larger notches and uneven substrates eat more adhesive and cover fewer feet, so the same 400 square feet at 50 square feet per bag would need 8.80 bags, order 9, not 11 — trowel size changes the count completely, even though the area and waste are unchanged. Check your adhesive maker’s coverage table for your notch size and substrate, and enter that figure rather than trusting the default for a different trowel.
Did you measure every area? The area entered here must be the total of all tiled surfaces, not the largest single room: a home with 400 square feet downstairs plus bathrooms, halls and backsplashes has more than 400 square feet to fix. The 200-square-foot branch needs 5.50 bags, order 6, against the 11.00-bag headline, so missing one room understates the order by whole bags on a bigger job. Measure every area, add them before dividing, and do not subtract small gaps unless your adhesive maker says to.
Are you counting waste, or a second layer? This page adds 10% for waste — cuts, spillage and back-buttering on awkward edges — and that is not a second layer. A second layer doubles the area first: 400 square feet twice-fixed is 800 square feet before waste, which is 880.00 square feet with waste and 22.00 bags, order 22. Treating a second layer as waste, or waste as a second layer, misstates the order by whole bags either way, so decide the layers first and let the waste percentage stay at waste.
Worked example
On the defaults: 400 square feet, 40 square feet per bag, 10% waste.
- Needed area: 400 × 1.10 is 440.00 square feet.
- Exact bags: 440.00 ÷ 40 is 11.00 bags.
- Order: 11.00 rounded up is 11 bags — an exact fit, so no extra bag is added by the rounding.
- Check: 11 bags cover 440 square feet, exactly the 440.00 needed; 10 bags cover only 400, which is not enough.
And the other way: the area behind 11.00 bags is 400 square feet, the coverage behind 11.00 bags is 40 square feet per bag, and the waste behind 11.00 bags is 10%. A job of 40 square feet at 0% waste orders exactly 1 bag, and a 1,000-square-foot job at 40 square feet per bag and 0% waste lands exactly on 25.00 bags, order 25.
Every branch, checked
- 200 square feet, 40 square feet per bag, 10% waste: 200 square feet, 40 square feet per bag, 10% waste: 5.50 bags exact — order 6 bags.
- 800 square feet, 40 square feet per bag, 10% waste: 800 square feet, 40 square feet per bag, 10% waste: 22.00 bags exact — order 22 bags.
- 400 square feet, 50 square feet per bag, 10% waste: 400 square feet, 50 square feet per bag, 10% waste: 8.80 bags exact — order 9 bags.
- 400 square feet, 40 square feet per bag, 20% waste: 400 square feet, 40 square feet per bag, 20% waste: 12.00 bags exact — order 12 bags.
The reverses, worked backwards
- Area behind 11.00 bags: 400 sq ft — at 400 sq ft the figures are 11.00 bags exact — order 11 bags.; at the lower neighbor the figures are 9.63 bags exact — order 10 bags.; at the upper neighbor the figures are 12.38 bags exact — order 13 bags..
- Coverage behind 11.00 bags: 40 sq ft per bag — at 40 sq ft per bag the figures are 11.00 bags exact — order 11 bags.; at the lower neighbor the figures are 14.67 bags exact — order 15 bags.; at the upper neighbor the figures are 8.80 bags exact — order 9 bags..
- Waste behind 11.00 bags: 10% waste — at 10% waste the figures are 11.00 bags exact — order 11 bags.; at the lower neighbor the figures are 10.50 bags exact — order 11 bags.; at the upper neighbor the figures are 11.50 bags exact — order 12 bags..
What the defaults assume
The defaults are 400 square feet, 40 square feet per bag and 10% waste, so the headline is one layer of adhesive over a medium tiled floor at a common notch size. 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. Bag coverage differs by trowel — the 40-square-feet figure is mid-range, and a larger notch covers fewer feet, so enter the coverage for the bag and trowel you will actually use. The area reverse is checked at 50 square feet either side, because 50 square feet at 10% waste is 55 square feet, about 1.38 bags; the coverage reverse is checked at 10 square feet either side, because 440.00 over 30 is 14.67 bags and over 50 is 8.80; the waste reverse is checked at 5% either side, because 5% of 400 is 20 square feet, exactly 0.50 bags. The model does not include second layers, tile itself, grout, backer board, fasteners, or tools — count those separately.
Lookup table: bags by area and waste
Each row already includes its waste allowance at 40 square feet per bag: needed area is the area times one plus the waste percentage, exact bags are needed area divided by 40, 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 bag coverage, enter your own figure in the calculator above: a larger notch covers fewer feet, so the order rises.
| Area | Waste | Needed area | Exact bags | Order |
|---|---|---|---|---|
| 100 sq ft | 0% | 100.00 sq ft | 2.50 | 3 bags |
| 100 sq ft | 5% | 105.00 sq ft | 2.63 | 3 bags |
| 100 sq ft | 10% | 110.00 sq ft | 2.75 | 3 bags |
| 100 sq ft | 15% | 115.00 sq ft | 2.88 | 3 bags |
| 200 sq ft | 0% | 200.00 sq ft | 5.00 | 5 bags |
| 200 sq ft | 5% | 210.00 sq ft | 5.25 | 6 bags |
| 200 sq ft | 10% | 220.00 sq ft | 5.50 | 6 bags |
| 200 sq ft | 15% | 230.00 sq ft | 5.75 | 6 bags |
| 400 sq ft | 0% | 400.00 sq ft | 10.00 | 10 bags |
| 400 sq ft | 5% | 420.00 sq ft | 10.50 | 11 bags |
| 400 sq ft | 10% | 440.00 sq ft | 11.00 | 11 bags |
| 400 sq ft | 15% | 460.00 sq ft | 11.50 | 12 bags |
| 800 sq ft | 0% | 800.00 sq ft | 20.00 | 20 bags |
| 800 sq ft | 5% | 840.00 sq ft | 21.00 | 21 bags |
| 800 sq ft | 10% | 880.00 sq ft | 22.00 | 22 bags |
| 800 sq ft | 15% | 920.00 sq ft | 23.00 | 23 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 | 11.00 bags — 440.00 ÷ 40. |
| Order | exact bags rounded up | 11 bags — 11.00 is already whole, so no extra bag. |
| Area behind a target exact figure | exact bags × coverage per bag ÷ (1 + waste ÷ 100) | 400 sq ft — 11.00 × 40 ÷ 1.10. |
| Coverage behind a target exact figure | needed area ÷ exact bags | 40 sq ft per bag — 440.00 ÷ 11.00. |
| Square feet covered by the order | order × coverage per bag | 440 sq ft — 11 × 40, exactly the 440.00 needed. |
| Square feet short on one fewer bag | needed area − (order − 1) × coverage per bag | 40.00 sq ft — 440.00 − 10 × 40, which is why rounding down fails. |
| 200 square feet, 40 square feet per bag, 10% waste | same model | 5.50 bags exact — order 6 bags. |
| 800 square feet, 40 square feet per bag, 10% waste | same model | 22.00 bags exact — order 22 bags. |
| 400 square feet, 50 square feet per bag, 10% waste | same model | 8.80 bags exact — order 9 bags. |
| 400 square feet, 40 square feet per bag, 20% waste | same model | 12.00 bags exact — order 12 bags. |
| Area behind 11.00 bags | reverse | 400 sq ft: 11.00 bags exact — order 11 bags. |
| Coverage behind 11.00 bags | reverse | 40 sq ft per bag: 11.00 bags exact — order 11 bags. |
| Waste behind 11.00 bags | reverse | 10% waste: 11.00 bags exact — order 11 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. |
| 40 square feet, 0% waste | same model | 1.00 bags exact — order 1 bag. |
Who uses this
- A DIYer fixing a new floor — 400 square feet at 10% waste is 11 bags, with the lookup table covering every other area and waste level without re-measuring.
- A tile installer ordering for a job — the branches show how the order moves with area, coverage and waste, so a larger notch is repriced before ordering.
- A homeowner comparing trowel sizes — the 50-square-feet branch shows what a smaller notch 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: bag coverage varies widely with notch size and substrate — a large notch on an uneven floor eats far more adhesive than a small notch on a flat floor — so check your adhesive maker’s coverage table for your trowel and enter your own figure when your notch differs. This page is a calculation tool, not trade advice — follow the adhesive maker’s instructions for mixing, open time and curing.
Cite this calculator
400 square feet at 10% waste with 40 square feet per bag coverage needs 440.00 square feet, 11.00 bags exact: order 11 bags. Source: Bright Side Kit, https://brightoolbox.com/tile-adhesive-chart/, accessed 29 October 2026.
Frequently asked questions
How many square feet does one bag of tile adhesive cover?
This page uses 40 square feet per bag, a mid-range figure for a standard bag at a common notch size. A larger notch covers fewer feet, so the same 400 square feet at 50 square feet per bag needs 8.80 bags, order 9 — the calculator divides by whatever you enter, so the answer stays honest for your trowel size.
Is tile adhesive the same as thinset?
Thinset is the most common kind of tile adhesive: a cement-based mortar spread with a notched trowel. Other adhesives, such as mastic, cover differently, which is why the two charts use the same divide-and-round-up arithmetic but different coverage figures — always enter the coverage for the product you will actually use.
Why add 10% waste?
Because material is lost to cuts, spillage and back-buttering on awkward edges: the 10% allowance covers the adhesive that never ends up as a finished bed. Without it, a job that computes to exactly 11.00 bags would run dry on the last stretch of floor, 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 tile unfixed: 5.50 bags rounded to the nearest is 6 here, but a 5.40-bag job rounded to the nearest is 5, and 5 bags cover only 200 of the 220.00 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 of 40 square feet at 0% waste 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 layer?
No: waste and layers are different things. Waste is the extra 10% for cuts, spillage and back-buttering on one layer; a second layer doubles the area first, so 400 square feet twice-fixed is 800 square feet before waste, which is 880.00 square feet with waste and 22.00 bags, order 22. Decide the layers first, then let waste stay at waste.