Taper Jig Angle Calculator
Tapered legs are a hallmark of clean furniture design, and cutting them safely depends on setting your taper jig to the right angle. A taper is fully described by three numbers: the wide-end width, the narrow-end width, and the length over which the taper runs. From these the offset is just the difference in widths, the jig angle is the inverse tangent of that offset over the length, and the taper per foot scales the offset to a 12-inch run. This calculator returns all three so you can set a degree-scale jig, an offset-style jig, or transfer the cut to a sliding table or band saw fence.
Taper jig angle formula
Offset = wide-end width - narrow-end width
Jig angle = arctan(offset / tapered length) in degrees
Taper per foot = (offset / tapered length) * 12
Taper ratio = tapered length / offset (run per unit rise)
The angle is measured from the original straight edge of the workpiece. The taper ratio expresses the slope as length of run for every unit of width offset.
Cutting tapers safely
- Enter the per-face offset; for a two-face leg taper, repeat the cut on each face with the same jig setting.
- The geometric angle is unaffected by the saw kerf, which is removed on the waste side of the line.
- Use a push block and keep hands clear; tapered offcuts can pinch between blade and fence if not supported.
- Mark layout lines from finished dimensions, then confirm the jig opening against those lines before cutting.
- A common furniture leg taper falls between half an inch and one inch per foot; steeper tapers look more dramatic.
Taper jig: frequently asked questions
How do I set the angle on a taper jig?
A taper is defined by how much the width changes over a length. The total offset is the wide-end width minus the narrow-end width. The jig angle equals the inverse tangent of that offset divided by the tapered length. Set your adjustable taper jig to this angle, or set the offset directly if your jig uses an opening width.
What is taper per foot?
Taper per foot expresses the offset as inches of width change for every 12 inches of length. It equals the offset divided by the tapered length, times 12. Furniture leg tapers are often quoted this way, for example a taper of three quarters of an inch per foot.
Is the taper on one side or both?
This calculator treats the offset as the difference between the wide width and the narrow width measured on the same face, which is a single-side taper. For a leg tapered on two adjacent faces, run the cut on each face in turn using the same jig setting; the per-face offset is what you enter.
Why use the angle instead of the offset?
Some taper jigs are set by an angle scale and others by an offset measured at a fixed point along the jig. Knowing both lets you use either style of jig, check one against the other, or transfer a taper to a sliding table saw or a band saw fence where you dial in degrees.
Does the calculator account for the saw kerf?
No. It gives the geometric angle and offset of the finished taper. The kerf is removed on the waste side of the line when the jig is set up correctly, so it does not change the taper angle. Mark your layout lines from the finished dimensions you enter here.
Official sources
- NIST Digital Library of Mathematical Functions: trigonometric functions (arctangent).
- USDA Forest Products Laboratory: machining and shaping of wood.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.