The formula
taper_rate = (start_width − end_width) / length
Start and end widths in inches, length is the run of the taper (not the leg’s overall length). Result is inches of width loss per inch of length — multiply by 12 for inches per foot. Convert to a jig angle with angle = atan(rate).
Example: Shaker side table leg
Start 1-3/4" at the apron, end 1-1/8" at the floor over a 28" taper. (1.75 − 1.125) / 28 = 0.0223 in/in, or about 0.27" per foot. On a tapering jig that’s 1.28° off square. Dead On gives both the rate and the jig angle in the same view — one to verify your design, one to set the jig.
Why it matters
A jig set 0.5° wrong over a 30-inch taper gives you a leg that’s nearly 1/4" off at the bottom. Four legs all wrong by different amounts and the table sits crooked. Consistent jig setup needs exact math, not eyeball-and-adjust.
Step-by-step
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1
Set start width
Width at the wide end — usually where the leg meets the apron.
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2
Set end width
Width at the narrow end — usually the floor.
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3
Set taper length
Run of the taper, not the leg’s overall length. The straight section above the taper isn’t included.
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4
Read the rate or angle
Per-foot for design verification; jig angle in degrees for saw setup.
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5
Build or adjust the jig
Most tapering jigs are adjustable wedges — set the angle, lock it, run all four legs from the same setup.
Skip the math. Build the diagram.
Dead On does the taper calculator and 12 other woodworking calculators with visual diagrams, offline, on every Apple device signed into your Apple ID.
Download Dead On — FreeFrequently asked questions
Should I taper one side or two?
Two-side tapers (front and side faces) read most strongly as Shaker. Four-side tapers look heavier and modern. Pick by style; the math is the same per side.
Where does the taper start?
Below the apron, almost always. A typical stopped taper leaves 4–6" of full-width stock at the top so the joinery has something solid to bite into.
Can Dead On render the leg?
Yes. The Pro version draws the leg in profile with the taper start, end, and angle labeled, so you can sanity-check proportions before milling.
Does the taper rate change for a stopped taper?
No. The rate is just rise over run. Whether it stops 4" below the apron or starts at the very top, the angle of the cut is the same as long as the start/end widths and the taper length are correct.