Taper Jig Calculator (Taper Angle and Jig Offset for Legs)

Tapered legs make a table look lighter, and a taper jig on the table saw makes them repeatable. The question is always how far to open the jig. Enter the leg width where the taper starts, the width you want at the foot, the length of the taper and the length of your jig, and this calculator gives the jig opening, the taper angle and the taper per foot. It covers the usual two-sided leg, tapered only on its inside faces, and the four-sided taper, where the setting has to be doubled for the last two cuts.

Taper jig calculator

How it works

A straight taper is a right triangle: the length of the taper and the amount removed from the face.

removed per face: two-sided leg (inside faces only) = top width − foot width; four-sided = half of that
taper angle = arctan(removed per face ÷ taper length)
jig opening = jig length × removed per face ÷ taper length
taper per foot = removed per face ÷ taper length × 12

The jig opening is measured at the stated distance from the hinge or the pivot end of the jig, square to its fence. Because the triangle is the same shape at any size, a longer jig just opens proportionally more; what matters is that the leg’s top sits at the hinge end where the taper starts.

Worked example

Legs 1-3/4 in square, tapered on the two inside faces to 1 in at the foot over the bottom 24 in, on a 24 in taper jig:

Units: Inches
Width where the taper starts: 1.75 in
Width at the foot: 1 in
Length of the taper: 24 in
Tapered faces: One face each way (legs tapered on the two inside faces)
Jig length, hinge or fence pivot to the stop: 24 in

The calculator gives:

Jig opening at 24 in: 0.75 in (about 3/4 in)
Taper angle (each tapered face): 1.79 degrees
Removed from each tapered face at the foot: 0.75 in (about 3/4 in)
Taper per foot (each face): 0.375 in (about 3/8 in)
Foot size after tapering: 1 in square

Each inside face loses 3/4 in at the foot, an angle of 1.79 degrees or 3/8 in per foot, and the jig opens 3/4 in at 24 in from the hinge. Cut one inside face, give the leg a quarter turn so the other inside face is outward, and cut again at the same setting. For a four-sided taper from 2-1/2 in to 1-1/2 in over 28 in on a 30 in jig, each face loses 1/2 in and the jig opens 0.536 in for the first two adjacent faces and twice that for the last two.

Taper angle by amount removed and taper length

Removed per face	12 in long	18 in long	24 in long	28 in long	30 in long
1/4 in	1.19°	0.8°	0.6°	0.51°	0.48°
3/8 in	1.79°	1.19°	0.9°	0.77°	0.72°
1/2 in	2.39°	1.59°	1.19°	1.02°	0.95°
5/8 in	2.98°	1.99°	1.49°	1.28°	1.19°
3/4 in	3.58°	2.39°	1.79°	1.53°	1.43°
1 in	4.76°	3.18°	2.39°	2.05°	1.91°

Angle = arctan(removed ÷ length). The jig opening at the end of a jig as long as the taper equals the amount removed.

Notes and limits

Start the taper a little below the apron, so the joint stays square and the apron shoulder sits on a flat face.
Always cut the joinery (mortises for aprons) while the leg is still square; tapered legs are hard to clamp and register.
Keep the waste side away from the fence and use a jig with a hold-down. Light tapers produce long thin offcuts that can kick back.
Plane or joint the sawn faces lightly afterwards; take the same number of strokes on each face so the taper stays even.
Curved rather than straight legs and aprons: the arc radius calculator.

Frequently asked questions

How do I set a taper jig?

Open the jig, at a set distance from its hinge, by that distance × the amount to remove ÷ the taper length. With a 24 in jig and a 3/4 in taper over 24 in, open it 3/4 in at the 24 in mark.

What is the angle of a taper?

arctan(amount removed ÷ length). Taking 3/4 in off over 24 in is 1.79 degrees, 3/8 in per foot.

Why do I double the setting for a four-sided taper?

After the first two adjacent faces are cut, the faces that ride on the jig for the last two cuts are already tapered, which takes away half of the angle. Doubling the opening puts it back.

How much should a table leg taper?

That is a design choice. Try two or three foot sizes in the calculator and compare the angles, or draw the leg full size on a board and look at it from across the room.

Sources

Wikipedia, "Slope": slope as rise over run and the angle as its arctangent

Last reviewed: 25 October 2026. The calculation is covered by automated tests with known answers taken from the sources above. Found an error? Please let us know.