Studio Matrx Monthly · Volume 1 · Issue 1 · June 2026
Amogh N P
 In loving memory of Amogh N P — Architect · Designer · Visionary 
Door Clearance Checker

Door Clearance Checker

Enter your measured gaps — head, hinge & lock stiles and the bottom undercut in mm — pick the door's use, and get a pass / fail against fitting tolerances (≈3mm head & stiles, 6-12mm undercut, fire ≤3mm) with a fix for every gap.

Your measurements

Everyday bedroom / living door. ~3mm margins, 8-12mm undercut for return air. Recommended for this use: head 2-4mm, stiles 2-4mm, undercut 8-12mm. Measure with feeler gauges or a steel rule along the height — gaps should be even top-to-bottom.

Normal internal — clearance check

0 / 4 gaps pass

Within tolerance — good to hang. Undercut ≈ 10mm.

Gaps passing

4 / 4

Undercut

10 mm

bottom clearance

  • Head (top) gap: 3mm (target 2-4mm) OK

  • Hinge-side stile gap: 3mm (target 2-4mm) OK

  • Lock-side stile gap: 3mm (target 2-4mm) OK

  • Bottom undercut: 10mm (target 8-12mm) OK

Measured vs recommended gaps

Your measured gap (green = pass, red = out of tolerance) against the recommended mid-point (teal) for a normal internal door. All values in mm.

100% of gaps within tolerance. Bars side-by-side: left = recommended, right = your measurement.

Sort out a sticking or gappy door

DesignAI reads your gap measurements and door use, then talks you through the safest fix — planing, shimming hinges, adding a threshold or seal — without weakening the leaf.

How to read this check

Hung-leaf gaps should be small and even: about 3mm at the head and along both stiles, with a 6-12mm bottom undercut on internal doors (10-12mm where carpet or return-air ventilation needs it; less where a threshold or drop-seal is fitted). Fire doors (FD30/FD60) close everything down to ≤3mm and use an intumescent/smoke seal with no large undercut. Gaps that are too tight make the leaf bind and stick; gaps that are too wide let in light, draught and noise.

Where the door meets a threshold, keep accessible thresholds ≤12mm, bevelled if over 6mm, ideally flush (RPwD / NBC), and make sure escape doors keep free egress. A plumb, square frame is non-negotiable — most uneven gaps trace back to a frame that isn't true, not the leaf. In India, keep a DPC / anti-termite treatment at the frame base.

These margins are indicative for India 2026 — confirm with your carpenter or fitter on site, and measure twice. This is a guidance tool, not a substitute for a skilled carpenter or site engineer. (No costs are calculated here; where any door work is invoiced, remember 18% GST applies on materials and labour.)