Toolpath offset
Offset magnitude = measured full kerf / 2Offset the path outward for an external part and inward for a hole or closed slot.
Laser cutting / dimensional compensation
Laser Kerf Compensation Calculator
Calculate one-side toolpath offset and pre-compensated path size from measured full kerf width and the type of cut feature.
Measure a coupon made with the same material, thickness, focus, power, speed, and assist gas.
Required finished outside size or finished hole/slot width.
Outside profiles grow; holes and closed slots shrink at the path-generation stage.
Formula, scope & sources
How this calculator works
CAD pre-compensation
External path = target + kerf; internal path = target − kerfUse this only when the laser software cuts on the supplied centerline and is not also applying kerf compensation.
Production application disclaimerDo not apply compensation in both CAD geometry and cutter software. Kerf varies with direction, material, thickness, optics, focus, power, speed, gas, and machine condition. Cut and measure a representative coupon before producing mating or tolerance-critical parts.
Reference basis: Rayforge MIT-licensed kerf implementation
Implementation: Original MfgWorkbench calculation code, independently verified against cited formulas and worked examples. Last reviewed September 4, 2026.