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Stain coverage chart & calculator
Put your area and coverage rate in: 400 sq ft at 250 sq ft a gallon with 10% waste orders 2 gallons.
★ CONSTRUCTION · DECK & FENCE · COVERAGE
Stain Coverage Chart: Gallons Needed by Area & Stain
On the defaults — a 400 sq ft deck at 250 sq ft a gallon with 10% waste — the adjusted area is 440.00 sq ft, the exact need is 1.76 gallons, so you order 2 gallons. This is the COVERAGE version — area divided by a maker coverage rate, rounded up — the fence-stain-calculator page is the FENCE version — linear fence length turned into gallons; the diy-vs-hire-deck-staining page is the COST version — doing it yourself against hiring it out; and the diy-vs-hire-fence-staining page is the FENCE-COST version — the same hire-or-DIY choice for a fence.
What does 2 gallons for a 400 sq ft deck mean?
It means the deck’s 400 sq ft, padded by 10% waste to 440.00 sq ft and divided by 250 sq ft a gallon, needs 1.76 gallons — and since stain is sold by the gallon, you buy 2. The rounding-up step is the whole point of the chart: 1.76 gallons is not a purchase, and running short mid-project costs more than the leftover quarter-gallon ever will.
Stain coverage chart
All figures include 10% waste and are rounded up to whole gallons — buy the table figure, not the exact decimal. The three rates are the low ends of published maker ranges: 200 sq ft a gallon for rough first coats, 250 for Olympic WaterGuard semi-transparent, and 350 for BEHR Premium penetrating oil semi-transparent (sources below the table).
| Area (sq ft) | 200 sq ft / gal | 250 sq ft / gal | 350 sq ft / gal |
|---|---|---|---|
| 100 sq ft | 1 gallons | 1 gallons | 1 gallons |
| 250 sq ft | 2 gallons | 2 gallons | 1 gallons |
| 400 sq ft | 3 gallons | 2 gallons | 2 gallons |
| 500 sq ft | 3 gallons | 3 gallons | 2 gallons |
| 750 sq ft | 5 gallons | 4 gallons | 3 gallons |
| 1,000 sq ft | 6 gallons | 5 gallons | 4 gallons |
| 1,500 sq ft | 9 gallons | 7 gallons | 5 gallons |
| 2,000 sq ft | 11 gallons | 9 gallons | 7 gallons |
Sources, accessed 2026-10-28: Olympic WaterGuard Semi-Transparent Wood Stain + Sealer product data sheet — coverage approximately 250 to 350 sq ft per gallon for one coat; BEHR Premium Semi-Transparent Waterproofing Stain & Sealer (water-based) — first coat 250–300 sq ft per gallon, second coat 500–600; BEHR Premium Semi-Transparent Penetrating Oil Wood Finish — 350–400 sq ft per gallon. The chart uses the low end of each range, so rough or weathered wood is planned for rather than hoped away. Always check your own product’s label: coverage figures on data sheets exclude loss from surface irregularities, porosity and application method.
Three things to check before you trust the number
Is the coverage rate your product’s rate? The defaults use 250 sq ft a gallon, the low end of Olympic WaterGuard’s published 250–350 range. A BEHR penetrating oil at 350–400 spreads much further, and a second coat spreads further still — BEHR’s water-based semi-transparent lists 500–600 sq ft a gallon for its second coat. Read your label, don’t guess.
Did you count railings and steps? The 400 sq ft headline is a deck floor only. Railings, steps and spindles add real area — measure them separately and add them to the area input before you trust the gallon count.
Is the wood rough or weathered? Rough, porous or weathered wood drinks stain, pushing coverage toward the low end of every range. The 200 sq ft a gallon column exists for exactly that case — a 1,000 sq ft rough deck needs 6 gallons there, not 5.
Worked example
On the defaults: 400 sq ft, 250 sq ft a gallon, 10% waste.
- The adjusted area: 400 × (1 + 10 ÷ 100) is 440.00 sq ft.
- The exact need: 440.00 ÷ 250 is 1.76 gallons.
- The order: rounding 1.76 up to the next whole gallon is 2 gallons.
And the other way: the area covered by 5 gallons at 250 sq ft a gallon with 10% waste is 1,136.36 sq ft, the coverage needed for 400 sq ft in 2 gallons with 10% waste is 220.00 sq ft a gallon, and the largest area (step 10 sq ft) covered by 2 gallons at 250 sq ft a gallon with 10% waste is 450 sq ft.
Every branch, checked
- 1,000 sq ft at 250 sq ft a gallon, 10% waste: 1,000 sq ft at 250 sq ft a gallon, 10% waste: 5 gallons to order (4.40 exact) for 1,000 sq ft at 250.00 sq ft a gallon with 10.00% waste — 1,100.00 sq ft adjusted.
- 400 sq ft at 350 sq ft a gallon, 10% waste: 400 sq ft at 350 sq ft a gallon, 10% waste: 2 gallons to order (1.26 exact) for 400 sq ft at 350.00 sq ft a gallon with 10.00% waste — 440.00 sq ft adjusted.
- 1,000 sq ft at 200 sq ft a gallon, 10% waste: 1,000 sq ft at 200 sq ft a gallon, 10% waste: 6 gallons to order (5.50 exact) for 1,000 sq ft at 200.00 sq ft a gallon with 10.00% waste — 1,100.00 sq ft adjusted.
- 400 sq ft at 250 sq ft a gallon, 0% waste: 400 sq ft at 250 sq ft a gallon, 0% waste: 2 gallons to order (1.60 exact) for 400 sq ft at 250.00 sq ft a gallon with 0.00% waste — 400.00 sq ft adjusted.
- 2,000 sq ft at 250 sq ft a gallon, 10% waste: 2,000 sq ft at 250 sq ft a gallon, 10% waste: 9 gallons to order (8.80 exact) for 2,000 sq ft at 250.00 sq ft a gallon with 10.00% waste — 2,200.00 sq ft adjusted.
- 250 sq ft at 250 sq ft a gallon, 10% waste: 250 sq ft at 250 sq ft a gallon, 10% waste: 2 gallons to order (1.10 exact) for 250 sq ft at 250.00 sq ft a gallon with 10.00% waste — 275.00 sq ft adjusted.
The reverses, worked backwards
- Area covered by 5 gallons at 250 sq ft a gallon with 10% waste: 1,136.36 sq ft — at the star the figures are 5 gallons to order (5.00 exact) for 1,136.36 sq ft at 250.00 sq ft a gallon with 10.00% waste — 1,250.00 sq ft adjusted.; at the lower neighbor the figures are 5 gallons to order (4.96 exact) for 1,126.36 sq ft at 250.00 sq ft a gallon with 10.00% waste — 1,239.00 sq ft adjusted.; at the upper neighbor the figures are 6 gallons to order (5.04 exact) for 1,146.36 sq ft at 250.00 sq ft a gallon with 10.00% waste — 1,261.00 sq ft adjusted. — verdict: STEP.
- Coverage needed for 400 sq ft in 2 gallons with 10% waste: 220.00 sq ft a gallon — at the star the figures are 2 gallons to order (2.00 exact) for 400 sq ft at 220.00 sq ft a gallon with 10.00% waste — 440.00 sq ft adjusted.; at the lower neighbor the figures are 3 gallons to order (2.01 exact) for 400 sq ft at 219.00 sq ft a gallon with 10.00% waste — 440.00 sq ft adjusted.; at the upper neighbor the figures are 2 gallons to order (1.99 exact) for 400 sq ft at 221.00 sq ft a gallon with 10.00% waste — 440.00 sq ft adjusted. — verdict: STEP.
- Largest area (step 10 sq ft) covered by 2 gallons at 250 sq ft a gallon with 10% waste: 450 sq ft — at the star the figures are 2 gallons to order (1.98 exact) for 450 sq ft at 250.00 sq ft a gallon with 10.00% waste — 495.00 sq ft adjusted.; at the lower neighbor the figures are 2 gallons to order (1.94 exact) for 440 sq ft at 250.00 sq ft a gallon with 10.00% waste — 484.00 sq ft adjusted.; at the upper neighbor the figures are 3 gallons to order (2.02 exact) for 460 sq ft at 250.00 sq ft a gallon with 10.00% waste — 506.00 sq ft adjusted. — verdict: STEP.
What the defaults assume
The defaults are 400 sq ft at 250 sq ft a gallon with 10% waste, so the headline is one coat on a small deck floor at a conservative maker rate. The model is one multiplication, one division and one round-up: area times one plus waste, divided by coverage, rounded up to whole gallons. The area reverse is checked at 10 sq ft either side, because 10 sq ft at 250 with 10% waste is 0.04 gallons — small enough to show the step cleanly; the coverage reverse is checked at 1 sq ft a gallon either side, because 1 sq ft a gallon either side of 220 flips the 400 sq ft order between 2 and 3 gallons. The model counts one coat only: a second coat needs its own calculation at its own (usually higher) coverage rate, and railings, steps and verticals must be added to the area first.
Output · formula · meaning
| Output | Formula | What it means |
|---|---|---|
| Adjusted area | area × (1 + waste % ÷ 100) | 440.00 sq ft — 400 × 1.10. |
| Exact gallons | adjusted area ÷ coverage per gallon | 1.76 gallons — 440.00 ÷ 250. |
| Gallons to order | CEILING(exact gallons) | 2 gallons — 1.76 rounded up. |
| 1,000 sq ft at 250 sq ft a gallon, 10% waste | same model | 5 gallons to order (4.40 exact) for 1,000 sq ft at 250.00 sq ft a gallon with 10.00% waste — 1,100.00 sq ft adjusted. |
| 400 sq ft at 350 sq ft a gallon, 10% waste | same model | 2 gallons to order (1.26 exact) for 400 sq ft at 350.00 sq ft a gallon with 10.00% waste — 440.00 sq ft adjusted. |
| 1,000 sq ft at 200 sq ft a gallon, 10% waste | same model | 6 gallons to order (5.50 exact) for 1,000 sq ft at 200.00 sq ft a gallon with 10.00% waste — 1,100.00 sq ft adjusted. |
| 400 sq ft at 250 sq ft a gallon, 0% waste | same model | 2 gallons to order (1.60 exact) for 400 sq ft at 250.00 sq ft a gallon with 0.00% waste — 400.00 sq ft adjusted. |
| 2,000 sq ft at 250 sq ft a gallon, 10% waste | same model | 9 gallons to order (8.80 exact) for 2,000 sq ft at 250.00 sq ft a gallon with 10.00% waste — 2,200.00 sq ft adjusted. |
| 250 sq ft at 250 sq ft a gallon, 10% waste | same model | 2 gallons to order (1.10 exact) for 250 sq ft at 250.00 sq ft a gallon with 10.00% waste — 275.00 sq ft adjusted. |
| Area covered by 5 gallons at 250 sq ft a gallon with 10% waste | reverse | 1,136.36 sq ft: 5 gallons to order (5.00 exact) for 1,136.36 sq ft at 250.00 sq ft a gallon with 10.00% waste — 1,250.00 sq ft adjusted. |
| Coverage needed for 400 sq ft in 2 gallons with 10% waste | reverse | 220.00 sq ft a gallon: 2 gallons to order (2.00 exact) for 400 sq ft at 220.00 sq ft a gallon with 10.00% waste — 440.00 sq ft adjusted. |
| Largest area (step 10 sq ft) covered by 2 gallons at 250 sq ft a gallon with 10% waste | reverse | 450 sq ft: 2 gallons to order (1.98 exact) for 450 sq ft at 250.00 sq ft a gallon with 10.00% waste — 495.00 sq ft adjusted. |
| 0 sq ft area | same model | Area — more than 0 sq ft. |
| 0 sq ft a gallon coverage | same model | Coverage per gallon — more than 0 sq ft. |
| 101% waste | same model | Waste factor — between 0% and 100%. |
| 0% waste on the 400 sq ft default | same model | 2 gallons to order (1.60 exact) for 400 sq ft at 250.00 sq ft a gallon with 0.00% waste — 400.00 sq ft adjusted. |
Who uses this
- A homeowner staining a deck this weekend — the 400 sq ft headline is the Saturday-morning question, answered as 2 gallons with the waste already in.
- A fence owner pricing the job — the table’s 1,000 and 1,500 sq ft rows cover most fence runs, and the 200 column covers weathered boards.
- A contractor quoting materials — the coverage reverse (220.00 sq ft a gallon for 400 sq ft in 2 gallons) checks whether a quoted product can actually do the job in the quoted gallons.
- A student learning rounding-up on real shopping — one worked example from area to adjusted area to exact gallons to whole gallons, with the branches that show why you never buy the decimal.
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 the order rounded up to whole gallons. The main limitation is the rate, not the arithmetic: published coverage ranges assume smooth, prepared wood and exclude application loss, so rough or weathered wood needs the low end of the range or the waste factor raised. The chart counts one coat; a second coat, railings, steps and verticals all need adding separately, and this page is a calculation tool, not product advice — always follow your stain’s label.
Cite this calculator
A 400 sq ft deck at 250 sq ft a gallon needs 2 gallons with 10% waste. Source: Bright Side Kit, brightoolbox.com.
Frequently asked questions
How many gallons of stain do I need for a 400 sq ft deck?
2 gallons at 250 sq ft a gallon with 10% waste. The adjusted area is 440.00 sq ft and the exact need is 1.76 gallons, rounded up to 2.
What coverage rate should I use?
Your product’s label rate — or the low end of its published range. Olympic WaterGuard semi-transparent lists 250–350 sq ft a gallon; BEHR penetrating oil lists 350–400. Rough wood should use the low end.
How much area do 5 gallons cover?
1,136.36 sq ft at 250 sq ft a gallon with 10% waste. At 1,126.36 sq ft you still order 5 gallons; at 1,146.36 sq ft you need 6.
How do I count railings and steps?
Measure them separately and add them to the area. The headline 400 sq ft is a deck floor only — railings and steps are extra surface, not free.
Do I need a second coat?
Most products perform better with one, and some require two. This chart counts one coat; a second coat needs its own calculation, usually at a higher coverage rate — BEHR’s water-based semi-transparent lists 500–600 sq ft a gallon for the second coat.
Why round up instead of buying the exact amount?
Because stain is sold by the gallon and running short mid-project breaks the finish. A leftover quarter-gallon is far cheaper than a second trip and a visible lap mark.
What if my area is 0?
That is an error, not 0 gallons. The calculator asks for an area of more than 0 sq ft — a 0 area means nothing was measured yet.