How to Measure a Fence for Stain

Count each face you intend to stain

For a uniform solid run, multiply run length by coated height and by the number of faces that will receive stain. A 100-foot run at 6 feet high has 600 square feet on one face, or 1,200 square feet on two. Measure runs with different heights separately and add their areas.

This mode counts the selected broad faces; it does not infer posts, caps, rails, or board edges. Measure those surfaces separately if they matter. Enter their summed coated area in Measured wood area rather than hiding measured surface inside an unexplained allowance.

1. List each run, gate face, rail, post, and other surface that will receive stain.
2. Measure solid-run length and coated height in feet.
3. Choose one face or both faces in solid-run mode.
4. Identify openings that remain uncoated; calculate their deduction across the selected faces.

Handle gates, gaps and exposed board edges explicitly

Deduct only an opening that will remain uncoated. For a 4-by-6-foot gateway in a run where both fence faces are selected, the opening occupies 4 × 6 × 2 = 48 square feet across those faces. Subtract 48 from the 1,200-square-foot gross area to get 1,152 square feet. If a wood gate fills that opening and both gate faces will be stained, measure and add the gate instead of deducting it.

Open picket, shadowbox, and board-on-board fences are not solid rectangles of exposed wood. Add the broad faces and any rails, posts, or edges you intend to coat. Enter that total in Measured wood area; this mode does not apply a second face multiplier.

Read the coverage basis before multiplying coats

Enter square feet per US gallon per coat. Confirm that the label’s coverage applies to the wood condition and application being planned. If documentation gives a total-system yield rather than a per-coat rate, resolve that basis before entering a coat count; otherwise the same coats can be counted twice.

This calculator applies one coverage value to every entered coat. If the first coat and later coats have different documented rates, calculate them separately and add the quantities. Do not force different rates into one field.

Lower coverage means more gallons. For the same 1,200-square-foot area and one coat, hypothetical rates of 150, 200, and 250 ft²/US gal produce 8, 6, and 4.8 US gallons. If the product gives a range for the applicable surface, calculate both endpoints instead of treating a midpoint as exact.

Turn the net area into gallons and whole containers

Once area, coverage, and coat count are established, enter an allowance only if you choose one. The percentage is a planning input; it is not a researched absorption factor. Keep actual detail surfaces in the measured area.

At 1,200 ft², 200 ft²/US gal per coat, and one coat, the estimate is 6 US gallons. If the available container size is 5 US gallons, 6 ÷ 5 = 1.2, so the whole-container count rounds up to 2. You would purchase 10 gallons in that package size, while the material estimate remains 6 gallons. The calculator does not combine different container sizes to optimize a purchase.

Net area = length × height × faces − total deductions. Gallons = net area ÷ coverage per coat × coats × (1 + allowance ÷ 100). Containers = gallons ÷ container size, rounded up.

Keep surface readiness separate from quantity

A quantity estimate cannot determine whether the wood is ready for stain. Check the selected product’s surface-preparation, existing-finish, moisture, and weather instructions. This calculator supplies no universal moisture threshold or drying time.

Before purchase, verify the run faces, gate surfaces, measured rails and posts, and opening deductions. Confirm that coverage is entered per coat. Correcting those inputs is more useful than applying an unexplained percentage to an uncertain area.

Independently worked examples

These assumed inputs illustrate the arithmetic. Use your measurements and the current instructions for your selected product.