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Picture frame wainscoting calculator

Wainscot boxes, chair rail, footage.

Open the Wainscoting · Picture Frame tool

Free. Runs in your browser, no account, and keeps working offline.

What it does

Enter the wall width, the height of the chair rail, the baseboard and how many boxes you want across. The calculator makes every box the same size with an equal reveal around each, and gives the left edge of every box measured from the corner.

Options cover what real walls need: a wider center box, more than one row, a mid rail, a taller top row, boxes above the chair rail, and an inset second frame inside each box.

It totals the molding for the boxes and the chair rail, so you know how much to buy before you go to the yard.

Worked example

A 10′ (120″) wall, chair rail top at 36″, 5 1/4″ baseboard, 3″ chair rail, four boxes across with a 3″ reveal around each.

Box width
26 1/4″
Box height
21 3/4″
Left edge of each box from the corner
3″, 32 1/4″, 61 1/2″, 90 3/4″
Try it with your numbers

Questions

How do I calculate wainscoting box sizes?

From the wall width subtract one reveal more than the number of boxes, then divide by the number of boxes. Height is the space between the baseboard and chair rail, less a reveal above and below.

How big should the space between boxes be?

Many installers use 3″ to 4″ between boxes and at the corners. Whatever you pick, keep it the same everywhere so the boxes read as one pattern.

Can I make the center box wider?

Yes. Turn on a wider center box and set how much wider; the side boxes shrink to fit and stay equal.

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