Best 3 Dovetail Layout Tools Compared

You have a board of some awkward width — 187mm, because that is what the timber gave you — and you want five tails evenly spaced across it with half-pins at each edge. Dividing by five gets you a number that does not account for the pins, and dividing by nine gets you something that looks wrong on the wood.

This is the arithmetic that stops people cutting dovetails by hand. It is not hard, but it is fiddly enough that a mistake costs a board rather than a rubbed-out pencil line, and the traditional dividers method — walking a pair of dividers across the work — takes practice to do reliably. A calculator turns it into marks you can transfer straight to the timber.

How to judge a dovetail calculator

Does it handle the half-pins? The edges are where the layout actually breaks. A calculator that divides the board evenly and ignores the end pins gives you a joint that looks wrong.

Does it warn about impossible layouts? Too many tails on a narrow board produces pins too thin to cut, and you want to know that before you reach for the saw.

Does it cover the ratio? 1:8 for hardwood and 1:6 for softwood are the conventions, and the ratio affects the geometry.

Does it give you marks or just widths? A tail width is a number. A list of positions measured from one edge is something you can transfer with a rule.

The comparison

Facts checked August 2026; plans can change.

WoodCalcs Dovetail Calculator

WoodCalcs is the most focused of the three on the question most people actually have. It computes dovetail pin and tail spacing for hand-cut or machine joints, spacing them evenly across the board width using traditional proportions, with no signup required. It also sits within a wider set of joinery calculators, so the mortise and tenon question you have next week is on the same site.

Its focus is spacing. Angle, ratio, and the geometry of the cheeks get lighter treatment than on the more elaborate tools, so if you are unsure which slope to use, you will be reading elsewhere.

Vriksai Dovetail Spacing Calculator

Vriksai’s is the most thorough. It computes tail count, angle, cheek, shoulder, and spacing using hardwood 1:8, softwood 1:6, and plywood 1:7 ratios, and produces a cut list alongside a canvas preview of the joint. Seeing the layout drawn before you mark it is a genuine check against a number you have typed wrong.

That thoroughness is more than a straightforward spacing question calls for. If you already know your ratio and just want the marks, there is a fair amount of output to read past.

CrunchMilk Dovetail Calculator

CrunchMilk keeps the inputs to three — board width, number of tails, and dovetail ratio — and returns tail width, pin width, and half-pin width. For someone who has done this before and wants the numbers without a lesson, that is the right level of abstraction.

It reports widths rather than cumulative positions. Turning a repeating tail-and-pin width into marks measured from one edge means adding as you go, which is exactly the arithmetic step where errors creep back in.

Dovetail Spacing Calculator

Ours takes a board width and a desired tail count and returns evenly spaced dovetail layout marks, with half-pins at each edge already included. The output is positions you can transfer directly to the wood rather than widths you have to accumulate. It runs entirely in your browser.

Two honest limitations. It handles even spacing, so if you want the graduated or hand-varied tail spacing that some furniture styles use for visual effect, you will be laying that out yourself. And it calculates the spacing, not the angle — the slope ratio you cut to is still your decision, and the calculator will not stop you specifying a tail count that leaves pins too fine for the timber you are working.

Which one to pick

• If you want even traditional spacing with nothing to configure, use WoodCalcs.
• If you want a drawn preview and a cut list with the ratio built in, Vriksai is the most complete.
• If you already know your ratio and just want widths, CrunchMilk is the fastest.
• If you want marking positions you can transfer straight to the board, use ours.

How to do it with Dovetail Spacing Calculator

1. Measure the actual board width — not the nominal size — and open the Dovetail Spacing Calculator.
2. Enter the width and the number of tails you want.
3. Transfer the marks to the end grain with a knife rather than a pencil.
4. Check the narrowest pin looks cuttable before you commit. More woodworking tools are in the tools directory.

You might also need

• Miter Angle Calculator — for the other joint on the same carcase.

Frequently asked questions

Is there a free dovetail calculator that doesn’t need an account?

Yes — WoodCalcs states no signup is required, Vriksai and CrunchMilk are free online tools, and ours requires no account because the site has no signup at all.

What dovetail ratio should I use?

The convention is roughly 1:8 for hardwoods and 1:6 for softwoods, the shallower slope suiting denser timber that resists splitting. The Woodwork Institute’s standards and most traditional texts treat these as guidance rather than rules — the joint works across a range, and consistency across the piece matters more than the exact figure.

How many tails should a board have?

There is no formula, only convention and proportion: wider boards take more tails, and traditional work often uses fewer, wider tails than machine-cut joints do. Lay it out and look at it before cutting — if the pins look mean, reduce the tail count.

Final thought

Calculate the spacing, then draw it and look at it before you saw. The arithmetic prevents the mistakes that cost a board; your eye is still what decides whether the joint looks right.

Try the free Dovetail Spacing Calculator