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Lid Fit Calculator — Tight-Fitting Box Lids

Calculate lid dimensions and clearance for tight-fitting box lids. Supports overlay, inset, rebated, and sliding styles.

How We Calculate This

This calculator determines the correct lid dimensions based on your box size, lid style, and desired clearance.

Lid styles

Overlay: Lid = External dimensions + overhang (typically 3mm per side).

Inset: Lid = Internal dimensions - clearance (0.5-1mm per side).

Rebated: Lid = External dimensions, with a step cut into the underside.

Sliding: Lid slides in grooves cut into the box sides.

Frequently Asked Questions

Last updated: February 2026

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