How to Measure Stair Angle for Handrail Installation
Short answer: to measure the stair angle for a handrail, rest a digital angle finder along the pitch line of the staircase (the step nosings) and read the degrees. Most UK domestic stairs sit between 30 and 42 degrees, with 42 the legal maximum for a private stair, and you cut the handrail ends to that rake angle. The LEXIVON Aluminum Digital Angle Finder (£33.19) reads and locks the rake so you can carry it to the saw.
What is the stair (rake) angle?
The rake angle is the pitch of the flight, measured from horizontal along the line that touches the front edge of each step. Under the UK Building Regulations (Approved Document K) a private domestic staircase must not exceed 42 degrees, and most comfortable stairs fall between about 30 and 38 degrees. Your own flight could be anywhere in that band, so measure it rather than copying a figure off the internet.
How to measure it
- Lay a long straight edge on the step nosings so it follows the pitch line of the flight
- Set the angle finder along that straight edge, or open one arm level and the other along the pitch
- Read the angle and press hold to lock it
Checking at the top, middle and bottom is worth it on an older staircase where steps have moved.
Turning the rake into cuts
A handrail runs parallel to the pitch, so the cuts where it meets a level section or a newel post are based on that rake angle. Transfer the locked angle straight to your mitre saw and, crucially, cut a test piece from an offcut first. A digital reading you can copy exactly is what lets you commit the expensive oak rail with one confident cut.
Safety and the rules
This is a job worth getting right: a toddler will pull on a banister, so the rail has to be secure. UK guidance requires a handrail on at least one side of the stairs and caps a private stair at that 42 degree pitch. Measuring accurately is part of a safe, compliant handrail, not just a neat one.
The LEXIVON angle finder is a 10-inch/250mm aluminium gauge, £33.19 inc VAT, with a 12-month warranty and UK support — a small outlay next to a length of hardwood handrail.
For the basics of reading and halving angles, see our digital angle finder UK guide and digital protractor buyer’s guide.
Frequently asked questions
What angle should stairs be in the UK?
A private domestic staircase must not exceed a pitch of 42 degrees under Approved Document K, and most comfortable stairs sit between 30 and 38 degrees. Measure your own flight rather than assuming.
How do I measure the rake angle of my stairs?
Rest a straight edge on the step nosings to follow the pitch line, set a digital angle finder along it and read the angle. Lock the reading so you can transfer it to your saw.
How do I cut a handrail to the stair angle?
Cut the rail ends to the measured rake angle so the rail runs parallel to the pitch. Always test the angle on an offcut before cutting the finished handrail.
How much is the LEXIVON angle finder?
The LEXIVON Aluminum Digital Angle Finder is £33.19 with a 12-month warranty, UK support, free UK delivery and 30-day returns.
Measure once, cut once.
See the LEXIVON Aluminum Digital Angle Finder — £33.19 inc VAT, free UK delivery, 30-day returns and a 12-month warranty with UK support.