Enter your observations
Use measurements you can verify. Unknown or unreadable details can be left unspecified where the tool allows it.
Existing hinge / mortise
Replacement hinge
Ready when you are
Your results will appear here without reloading this page.
How to use this tool
- Measure the existing hinge leaf and pin, and record mortise depth separately.
- Measure the available hinge-side gap and expected clearance needed for the door to swing.
- Enter replacement dimensions and choose a tolerance based on measurement accuracy.
- Review differences, then verify screws, timber strength, barrel geometry and door swing before installing.
What the result means
Leaf height, leaf width, pin diameter, leaf thickness and mortise depth describe different fit relationships. A hinge with a suitable leaf footprint can still sit proud if its mortise is too shallow, or fail to swing cleanly if the pin/barrel and surrounding gap are incompatible.
The tool compares the common matching dimensions, subtracts mortise depth from the entered replacement leaf thickness as a rough note, and compares recorded gap with a user-entered minimum clearance. This is a measurement aid rather than a load calculation.
Limits and good practice
The material-remaining display is only arithmetic and is not a structural assessment. Historic wood may be brittle, split, repaired or thin at a mortise. Hinge load depends on hinge construction, screws, attachment substrate, door weight and leverage. Valuable furniture should be assessed before enlarging or deepening a mortise.
References and further research
Frequently asked questions
Is mortise depth the same as hinge thickness?
No. Leaf thickness is the hinge material thickness; mortise depth is how deeply that leaf sits into the furniture or door edge.
What does the clearance check mean?
It compares your recorded gap with your stated required gap. Actual swing geometry may require a hands-on check.
Can the calculator determine how many hinges I need?
No. Hinge count is recorded for the measurement sheet only. Use documented load ratings and account for the door’s size and weight.
Why measure pin diameter?
Pin and barrel dimensions affect fit and can vary even when hinge leaves look similar.
Should I deepen an old mortise to fit a new hinge?
Not before considering conservation impact and surrounding timber condition. Deepening can remove original material or weaken the edge.
Can I print the measurement sheet?
Yes. Use the Print / Save PDF button to retain the values and comparison results for a repair record.