Wood & Trim

Wainscoting Calculator

Lay out equal wainscoting panel openings across a wall, with stile positions.

Units

Your measurements

Results update as you type.

Example shown — use your own measurements.

Fractions and number formats

Use decimals (12.5), fractions (12 1/2 or 12-1/2), or explicit lengths (12ft 6in, 12′ 6″, 25 mm). A comma followed by one or two digits is a decimal comma: 12,5 = 12.5. Grouped commas mean thousands: 1,200 = 1200. Use a decimal point for ambiguous values. Scientific notation is not accepted.

Enter your measurements

Results update as you type.

About this calculator

Enter the wall width, the number of panel openings and the stile (vertical trim) width. The tool computes equal panel opening widths and the position of every stile — the layout diagram and a text table always agree, because both come from the same numbers.

How to use this calculator

  1. Measure the wall width between corners.
  2. Choose the number of panel openings.
  3. Measure the stile width of your trim.
  4. Calculate; transfer the stile positions to the wall from one end.

Formula

Panel opening = (wall width − (panels + 1) × stile width) ÷ panels

Stile positions are measured from the left edge, alternating stile and opening

Assumptions

  • Stiles at both ends, so panel count + 1 stiles.
  • All panel openings are equal width.
  • A panel opening must be positive — too many panels or too-wide stiles is an error, not a negative number.

Common mistakes

  • Leaving out one of the two end stiles.
  • Measuring panel spacing from the wrong edge reference.
  • Forgetting outlets, doors and out-of-plumb walls in a final layout.

Worked example

Try it: press “Load example” above the form.

A 3 m wall with 4 panels and 90 mm stiles leaves (3000 − 5 × 90) ÷ 4 = 637.5 mm openings.

Limitations

Not a structural design. Panel opening must remain positive; reduce panel count or stile width if it does not.

Frequently asked questions

Do the end stiles count?

The model includes one more stile than panel openings, with an end stile at each side. The remaining width is divided into equal clear openings.

Does it plan uneven walls?

No. It assumes one straight measured width. Outlets, doors, corners, rails and out-of-plumb walls need a detailed layout before cutting.

What does the worked example show?

A 3 m wall with 4 panels and 90 mm stiles leaves (3000 − 5 × 90) ÷ 4 = 637.5 mm openings.

Which assumptions should I check before using the result?

Not a structural design. Panel opening must remain positive; reduce panel count or stile width if it does not.

Reviewed by Codex AI editorial agent (Editorial, 2026-11-12).

Sources

Sources explain the methods and any named product presets. Check your product label where coverage, yield or density differs.

Calculation documentation · Updated 2026-11-08 · Version 1.6.4. Estimates are planning aids. Confirm quantities, coverage and prices with your supplier before purchasing. Found an error? Report it.

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