Use this door size calculator to estimate door leaf size from an opening, or estimate rough opening size from a known door size. Enter the width, height, door type, and quantity to prepare a clearer quote request.
Calculate Door Size
The estimate updates automatically. Use preset allowances for a quick estimate, or choose custom allowance when your project has a specific frame requirement.
What Is a Door Size Calculator?
A door size calculator is a measurement tool that estimates door leaf size or rough opening size from the dimensions you already have. It helps buyers prepare cleaner interior door or steel exterior door requests before final production confirmation.
How to Calculate Door Size?
To estimate door size from an opening, subtract the total frame and fitting allowance from the rough opening width and height. To estimate rough opening from a known door size, add the required allowance back to the door width and height.
Door size = rough opening – allowance. Rough opening = door size + allowance.What Is the Best Door Size Calculator for Wholesale Orders?
The best door size calculator for wholesale orders should include the door type, quantity, width, height, allowance, and a quote-ready summary. Final dimensions should still be confirmed with the supplier because frames, thresholds, wall thickness, and opening direction can change the order specification.
