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What it means

Kerf is the width of the slot a saw blade cuts through material. Every cut destroys a strip of material equal to the kerf width. Over many cuts it adds up — 10 cuts with a 1/8" kerf removes 1.25" of material from your stock.

Kerf width varies by tool: table saw 0.125" (1/8"), miter saw 0.118", circular saw 0.094" (3/32"), bandsaw 0.032" (1/32"), Japanese pull saw 0.016", laser 0.004"-0.02" depending on power, waterjet 0.04".

Examples

8-ft stock, 10 rip cuts at 1/8" kerf

10 × 0.125" = 1.25" of material gone

Same on a bandsaw (1/32")

10 × 0.031" = 0.31"

Do

Add kerf to your cut length when ripping strips — a 48" rail cut from a 48" board yields a 47.875" rail.

Don't

Plan tight joints assuming zero kerf — always allow at least the kerf plus a safety margin.

Related terms

Board Foot

Lumber volume unit: 144 cubic inches. A 1"-thick × 12"-wide × 1-ft-long board is 1 board foot.

Calculators that use this

Kerf Allowance

How much material a saw blade eats across multiple cuts — ripping, crosscuts, bandsaw, laser.

Plywood Sheet Layout

Maximize pieces per 4x8 or 5x5 sheet — best orientation, kerf allowance, and waste percentage.

Board Feet

Convert lumber dimensions to board feet and project cost — the standard unit for buying rough lumber.