Fence stain calculator

How much stain do I need for a fence?

Measure the length and height you will coat, choose one or both faces, then select the actual stain formula. The tool calculates the rectangular surface area and uses that product's first- and second-coat coverage. The final purchase estimate rounds up to whole US gallons after combining the coat quantities.

Keep the area measurement separate from the gallons. A fence has the same face area when you change stain products, but the coverage rate can change the amount needed. A second coat also has its own coverage rate in the selected sheets, so doubling a first-coat gallon count is not the calculation used here.

Coverage by stain type and product

Solid, semi-transparent and transparent describe the product choices, not universal coverage classes. These rates belong to the named formulas. If your can has a different product number or application instruction, use its current sheet instead of assuming another stain of the same opacity covers the same area.

The BEHR solid sheet recommends two thin coats. The KILZ semi-transparent and BEHR transparent sheets require two. A one-coat selection estimates only that coat's quantity; it does not override the complete application directions. Follow the product you buy for surface preparation, drying and recoating.

Choose the appearance using a prepared test area before buying the full quantity. A coverage calculation cannot predict the final color on old and new boards or decide whether the existing finish is suitable for the new product. Keep the product name and color with the project notes so later maintenance can be matched.

Worked examples for common lengths and heights

These examples assume both faces and two coats. The lengths and heights are illustrative inputs; area is length × height × faces. Each gallon range uses the complete product-specific coverage interval and rounds the combined purchase upward. Extra exposed edges, separate framing surfaces and application loss are excluded.

The same fence size gives different gallon ranges because the sheets publish different coverage. Do not add the product columns together: each is an alternative complete coating estimate. The low-gallon result assumes the higher published coverage; the high-gallon result uses lower coverage and is the more conservative planning quantity.

Changing height changes the measured area, not the stain's spread rate. If the fence has sections of different heights, calculate them separately and add the unrounded product requirements before rounding the entire purchase. Adding separately rounded whole-gallon estimates can overstate the combined quantity.

One coat, two coats, one side or both sides

The next table holds the example at 100 ft long and 6 ft high using the selected solid formula. It changes only faces and coats. “Both sides” means coating both broad faces; it does not automatically measure every board edge or the exposed rail surfaces.

Coating both faces doubles the flat surface area before any gallon rounding. Moving from one coat to two adds the second-coat requirement calculated at its own rate. Whole-gallon rounding can make a small change appear larger or smaller than the change in exact liquid quantity.

If only one face is accessible, calculate that face and record the uncoated areas. Check the manufacturer's directions for the intended application before treating a partial coating as complete. Get permission and arrange access before planning to work from a neighboring property.

How the fence stain calculator handles rounding

For a worked semi-transparent example, 100 ft × 6 ft on one face gives 600 sq ft. At the higher published spread rates, the first coat needs 2.00 gallons and the second needs 1.00 gallons. The lower spread rates require 2.40 and 1.20 gallons respectively.

Adding each pair before rounding produces a whole-gallon purchase range of 3–4 US gallons. That order matters: rounding every coat up separately would be a different purchasing method. The calculator also keeps surface area separate from area across coats, so you do not accidentally multiply by the coat count again.

Package sizes are a purchasing decision after the liquid estimate. The tool reports US gallons, not cans or buckets, and assumes no particular container discount. Compare the available sizes for the exact formula and color without substituting a generic price per gallon.

Smooth versus rough wood and coverage uncertainty

The cited sheets publish ranges and do not assign a separate numeric rate to each texture. Both texture selections therefore retain the sourced coverage range. Selecting rough wood shows a reminder to plan toward the larger gallon amount; selecting smooth wood does not guarantee maximum coverage.

Check a test area on the prepared fence before committing to the full order. If the actual product consumption is outside the example, use the observed area and liquid used to revise the purchase plan. Do not spread stain more thinly than its directions just to reach the optimistic end of the calculator's range.

Application loss is separate from the surface coverage. The KILZ sheet explicitly excludes spray loss. This tool adds no assumed overspray percentage: ask the applicator how the chosen method, masking and site access affect the quantity. The larger gallon estimate is not a quantified allowance for every possible loss.

Measure boards, gates and framing accurately

For a solid flat face, length times height is a starting area. Subtract openings you will not coat from the entered length. Include a gate if it will receive the same coating, or measure it separately if its height or construction differs. Avoid counting the opening and a separate gate rectangle twice.

For spaced pickets, overlapping boards or shadowbox construction, a plain rectangle does not describe every exposed surface. Measure the board faces and edges you will coat, and account separately for exposed posts, rails and trim. The wood privacy guide explains the building parts; the coating takeoff still needs the surfaces you actually plan to finish.

Keep a short worksheet by section, product and coat count. If the back face is coated differently from the front, calculate those scopes separately. This makes it easier to explain an applicator's quantity and avoids buying the full fence area in each of two different finishes.

When should you restain a fence?

Follow the maintenance directions for the coating already on the wood. As a product-specific example, Ready Seal's maintenance FAQ recommends light cleaning and recoating every 3–4 years on vertical surfaces. Its FAQ notes that some dense hardwoods may need yearly reapplication. That schedule belongs to Ready Seal; it is not a promised interval for the BEHR or KILZ formulas in this calculator.

Inspect the finish and compare its condition with the selected manufacturer's guidance. If appearance or coating condition changes, identify whether the surface needs cleaning, preparation or recoating before ordering stain. A warranty period is not an instruction to wait that long, and a calendar interval cannot tell you the state of every face of a fence.

For an existing failing coating, review the relevant data sheet's preparation directions before applying another layer. The linked BEHR sheets describe cleaning or stripping where needed and require a dry prepared surface. Extra product applied over an unsuitable base does not replace that preparation.

DIY quantities versus an applicator's quote

Ask an applicator to state the coated faces, included gates and framing, product name, coat count and preparation scope. Compare that specification with your measured area. A higher gallon count may include surfaces omitted from a simple rectangle; ask for the measurement before concluding that either estimate is wrong.

For DIY work, read the product instructions for application conditions and equipment before buying. Include preparation supplies and access arrangements in your own list. No stain cost or labor rate is added here because a comparable verified price for the selected formulas and complete work was not established.

Complete needed structural work before finishing. The repair and replacement guide helps separate that work, and the post tool plans a new layout. Use the main fence calculator for a construction material list; this page estimates the separate coating purchase.