What slope ratio should I use for dovetails?

Use 1:6 for softwoods (steeper angle for better grip in softer fibres) and 1:8 for hardwoods (shallower angle to prevent short grain breakout). 1:7 is a good general-purpose compromise. The ratio describes the rise to run of the tail angle.

How wide should dovetail pins be?

Pin width is a matter of style. Fine pins (London pattern) are narrow and decorative. Equal pins and tails look balanced. Traditional tails are wider than pins for maximum mechanical strength. Fine pins are typically 3-5mm at the narrow end.

What is a half pin and why do I need them?

Half pins are narrow pins at each edge of the board. They prevent the joint from opening at the edges under stress. Without half pins, the end grain of the tail would be visible at the corner. The half pin width is typically half the board thickness.

What is the difference between through and half-blind dovetails?

Through dovetails are visible from both sides and are the strongest. Half-blind dovetails are hidden from the front, used in drawer construction where you want a clean face. Sliding dovetails are used for shelves and dividers in a housing channel.

WoodCalcs

Dovetail Spacing Calculator — Joint Layout

Calculate dovetail tail and pin spacing, slope ratio, and layout marks for hand-cut or machine joints.

Board Width

Width of the board to joint

Board Thickness

Thickness of each board

Dovetail Type

Select the dovetail type for your calculation

Pin Size Preference

Select the pin size preference for your calculation

Wood Hardness

Select the wood hardness for your calculation

How We Calculate This

This calculator determines the layout for dovetail joints based on board width, thickness, and style preference. It calculates the number of tails, their width, pin width, and exact positions from the edge.

Layout method

Half pins are placed at each edge (default: half board thickness)
Remaining width is divided into tails and pins
Tail width targets the board thickness for proportional appearance
Pin width is determined by the style preference (fine/medium/traditional)

Slope ratios

Softwood: 1:6 (steeper, ~9.5°)
Medium: 1:7 (~8.1°)
Hardwood: 1:8 (shallower, ~7.1°)

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.