Order fence stain and deck stain as two lines. Start from the measured area of each surface, divide by the coverage rate on the label of the product you will buy, add the coats the label requires, and round each line up to whole cans. A single combined gallon total hides which surface was short when the job runs out.
How much stain do I need for a fence and a deck?
Divide each measured area by its label coverage rate, coat by coat, then round each surface up to whole cans. The fence line and the deck line stay separate because they often use different products, different rates, and different coat counts.
Write 12 to 15 gallons at 100 to 125 ft² per gallon rather than recording 12 to 15 gallons alone. A later reader cannot check a total without the rate that produced it.
What is the ordering formula?
Gallons for one coat = stainable area ÷ label coverage rate for that coat
Cans to buy = total gallons ÷ can size, rounded up to a whole can
Two coat jobs need one of two methods, and the two methods must not be mixed in one line. When the label gives a rate for each coat, add the coats: gallons for the first coat plus gallons for the second coat. When the label gives a two-coat average rate instead, divide the area by that average once. TWP uses the average method on its calculator: TWP 100 and 1500 Series cover 150 to 200 ft² per gallon for the first coat and average 100 to 125 ft² per gallon across two coats.
| Method | Calculation | Use it when |
|---|---|---|
| Per-coat rates | (area ÷ first-coat rate) + (area ÷ second-coat rate) | The label gives a rate for each coat |
| Two-coat average | Area ÷ two-coat average rate | The label gives one average rate for two coats, as TWP does |
| One coat | Area ÷ single-coat rate | The label calls for one coat, as the Cabot semi-transparent record does |
Which coverage rate applies to your job?
Use the rate for the product you will buy, on the surface you will stain, in the condition it is in. A smooth board and a rough-sawn board do not share a rate even for the same product, and a fence rate does not transfer to a deck floor.
| Product record | Stated coverage | Scope note |
|---|---|---|
| TWP 100 and 1500 Series | 150-200 ft²/gal first coat; 100-125 ft²/gal average across two coats | Those product lines only, from the TWP calculator |
| Cabot Semi-Transparent Deck and Siding Stain | 250-350 ft²/gal smooth wood; 100-200 ft²/gal rough wood | That product line only; one-coat application on the product record |
| Angi general deck range | 150-225 ft²/gal commonly | General reference only; the selected product record controls |
A rate range gives a gallon range. Order from the full range, not from its midpoint, because the low end of the rate range sets the high end of the order. For a two-coat job, that means dividing by the low rate gives the larger gallon figure, and that larger figure is the one that keeps the job from running short.
How do you turn gallons into cans?
Stain is sold in whole containers, so a fractional gallon total always rounds up. TWP lists its stain in 1-gallon and 5-gallon sizes, and Sherwin-Williams lists SuperDeck in 1-gallon and 5-gallon options, so those two sizes are the working pair for the combinations below. Confirm the sizes your product is sold in before you use them, because sizes vary by brand and store.
| Gallon range | All 1-gallon cans | With 5-gallon pails |
|---|---|---|
| 6 to 9 gallons | 6 to 9 cans | 1 pail plus 1 to 4 cans |
| 12 to 15 gallons | 12 to 15 cans | 2 pails plus 2 to 5 cans |
Round each surface line up before you combine anything, and combine only lines that share the same product and color. A 5-gallon pail plus single cans also leaves fewer opened containers at the end of the job than the same total in single cans alone, which matters when the remainder is kept for touch-ups.
Worked order: a fence and a deck together
Take the areas from the measurement guide: a solid fence of 120 linear feet at 6 feet high, both sides stained, gives 1,440 ft² (133.78 m²). A deck floor of 16 by 20 feet plus one 5-step stair gives 350 ft² (32.52 m²). Railing stays on its own planning line of 28 linear feet at 10 to 15 ft² per linear foot, or 280 to 420 ft². Order all three lines at the TWP two-coat average of 100 to 125 ft² per gallon.
| Line | Area | Gallons before rounding | Order |
|---|---|---|---|
| Fence, both sides | 1,440 ft² | 1,440 ÷ 125 = 11.52 to 1,440 ÷ 100 = 14.4 | 12 to 15 gallons |
| Deck floor plus stairs | 350 ft² | 350 ÷ 125 = 2.8 to 350 ÷ 100 = 3.5 | 3 to 4 gallons |
| Railing, planning line | 280 to 420 ft² | 280 ÷ 125 = 2.24 to 420 ÷ 100 = 4.2 | 3 to 5 gallons |
| Deck total | 630 to 770 ft² | 6 to 9 gallons |
In cans, the fence line is 2 five-gallon pails plus 2 to 5 one-gallon cans, or 12 to 15 one-gallon cans. The deck total is 1 five-gallon pail plus 1 to 4 one-gallon cans, or 6 to 9 one-gallon cans. The fence and deck totals are ordered separately even when the color matches, because the fence product and the deck-floor product can differ, and a gallon counted for one surface cannot cover the other.
Worked example: smooth wood versus rough wood
Use the same 350 ft² deck area with the Cabot semi-transparent record, which calls for one coat. On smooth wood at 250 to 350 ft² per gallon, the order is 350 ÷ 350 = 1.0 to 350 ÷ 250 = 1.4, rounded up to 1 to 2 gallons. On rough wood at 100 to 200 ft² per gallon, the same area needs 350 ÷ 200 = 1.75 to 350 ÷ 100 = 3.5, rounded up to 2 to 4 gallons.
Rough wood roughly doubles the order on the same area. That is why the surface condition belongs on the order line beside the rate: a smooth-wood order applied to rough boards runs out about halfway through the job.
Why do fence and deck stay on separate order lines?
Three differences break a combined total. First, the products can differ: a fence product is not automatically rated for a deck floor, so the floor needs its own floor-rated product. Second, the rates differ: the fence rate and the deck rate come from different labels or different surface conditions. Third, the coat counts can differ: a one-coat fence product and a two-coat deck product cannot share one division. Keep the fence gallons, the deck gallons, the product name, the rate, and the coat count on separate lines, and the order can be checked line by line at the store.
What about spare stain for touch-ups?
Rounding up already leaves a remainder, and that remainder is the first touch-up stock. A gallon total of 11.52 rounded up to 12 leaves 0.48 gallons spare, and a total of 14.4 rounded up to 15 leaves 0.6 gallons spare. When the remainder is small and the job is large, add one extra can as its own line before you round, so the decision is visible on the order. Do not add a percentage for waste: no single percentage fits every product, surface, and application method, and a percentage hides the real remainder that rounding already produced. Keep the spare in its original container, sealed, and check the label for storage limits before the next season.
Common fence and deck ordering mistakes
- Using a smooth-wood rate on rough-sawn boards.
- Ordering two coats at the first-coat rate instead of the per-coat or average method.
- Counting one fence side and forgetting the second side.
- Pooling fence and deck gallons that use different products or colors.
- Forgetting railing, stairs, fascia, and skirt boards, then treating the floor area as the whole deck.
- Using a paint or siding coverage rate for stain, or a fence stain rate for a deck floor.
- Ordering an exact fractional gallon total instead of rounding up to whole cans.
- Recording one combined total that no one can re-check against a label rate.
Safety and professional scope
Ordering does not select the stain, the preparation method, or the application method. Follow the product label for surface preparation, temperature limits, recoat timing, ventilation, cleanup, and disposal, and follow the project safety plan for work at height and on wet or uneven ground. Check local VOC rules and any project specification before buying, and bring in a qualified professional when the structure, the old coating, or the preparation step is outside a standard stain job.
Sources and scope
- TWP, deck stain calculator: deck area as flooring plus railing plus steps; fence as length × height × 2; TWP 100 and 1500 Series first-coat and two-coat coverage figures.
- TWP, Semi-Solid Pro-Series product page: gallon sizes of 1 and 5, coverage 150-250 ft² per gallon for that line.
- Cabot Semi-Transparent Deck and Siding Stain, Do it Best product record: 250-350 ft² per gallon smooth wood, 100-200 ft² per gallon rough wood, one-coat application.
- Angi, How Much Stain Do I Need For My Deck: floor length × width plus side pieces, railings, and stairs; common coverage 150-225 ft² per gallon.
- Angi, How Much Stain Do I Need For My Fence: length × height per side, both sides × 2.
- NIST Handbook 44, 2026 Appendix C: square-foot to square-metre relationship.
Scope: the formulas turn stated stainable areas into whole-can orders. They do not measure the area, choose the stain, or approve surface preparation. The selected product's current label controls the coverage rate, coat count, container sizes, and final order quantity.
Review responsibility: Saleem Sial owns the published calculation, source, and editorial checks. Waseem Sial, External Reviewer and Engineer, remains listed for ongoing external review; no completed external-review date is claimed.
Next, measure the job with the fence and deck measurement guide, choose the product with the fence and deck stain guide, or return to the Paint Calculator with the measured areas from this page.
