Short answer
A 100 ft long, 6 ft high fence, stained on both sides with 1 coat, needs 8 gallons of stain at 150 sq ft per gallon. For 2 coats, the same fence needs 16 gallons. Use the formula below with your own fence size and your own stain can's coverage number, or try the Fence Stain Calculator for an instant result.
The formula
Gallons = length × height × sides × coats ÷ coverage per gallon, rounded up. Always round up to a whole gallon, because you cannot buy part of a gallon and you will want a little left for touch-ups.
Worked example: 100 ft × 6 ft fence
Step 1: one side is 100 × 6 = 600 sq ft. Step 2: both sides are 600 × 2 = 1,200 sq ft. Step 3: for 1 coat, divide by the coverage: 1,200 ÷ 150 = 8 gallons. Step 4: for 2 coats, double it: 8 × 2 = 16 gallons. That is the same result the Fence Stain Calculator gives for these numbers.
How much stain for common fence sizes
Both sides, at 150 sq ft per gallon, rounded up to whole gallons. A 5-gallon bucket holds 5 gallons, so divide the gallons by 5 and round up to get the number of buckets.
| Fence (length × height) | Area, both sides | 1 coat | 2 coats | 5-gallon buckets (1 coat) |
|---|---|---|---|---|
| 50 ft × 6 ft | 600 sq ft | 4 gallons | 8 gallons | 1 |
| 100 ft × 4 ft | 800 sq ft | 6 gallons | 11 gallons | 2 |
| 100 ft × 6 ft | 1,200 sq ft | 8 gallons | 16 gallons | 2 |
| 150 ft × 6 ft | 1,800 sq ft | 12 gallons | 24 gallons | 3 |
| 200 ft × 6 ft | 2,400 sq ft | 16 gallons | 32 gallons | 4 |
How to measure your fence
Measure the length along the fence, including gates, and add the sections together. Measure the height from the ground to the top of the boards. If you are staining only one side, use 1 side in the formula instead of 2. If your neighbour's side is already stained, count only your side.
What changes the number
The coverage number on your stain can matters most. Rough or weathered wood drinks more stain than smooth wood, so the label's top coverage number may be too generous for a rough fence. A second coat also changes the total, because it doubles the coverage area. When in doubt, use the lower coverage number, round up, and keep a little extra for touch-ups.
Common mistakes
The most common mistake is counting only one side of the fence, which halves the answer. The next is forgetting the second coat. The third is using the label's maximum coverage on rough wood. Check all three before you buy.
Try it with your own numbers
Open the Fence Stain Calculator, enter your fence length, height, coats and your can's coverage number, and it gives the gallons and an estimated cost. For the fence itself, see the Fence Calculator. For a deck, see the Deck Stain Calculator, and for a room, see the Paint Calculator. More guides are on the BuildCalc Blog and in Construction calculators.
Results are estimates and general information only. Always check your stain can's label and confirm final quantities with your supplier or a qualified professional.