How to Measure for a Stair Handrail

Getting accurate measurements before ordering a stair handrail saves time, money, and frustration. This guide covers everything you need to measure for both wall-mounted and ground-mounted handrails.

The short version: take your nose-to-nose measurement — the diagonal from the front edge of your top step to the front edge of your bottom step — then add 6 to 12 inches at each end. That total is the length to order.

Want it worked out for you? Use our handrail length calculator — enter your measurements and it returns the length to order, the bracket count, and whether the rail ships in one piece.

What You Will Need

• Tape measure (25-foot minimum)
• Pencil and notepad
• Level (4-foot recommended)
• A helper (optional but useful for long runs)

Measuring for a Wall-Mounted Handrail

1. Take Your Nose-to-Nose Measurement

The nose-to-nose measurement is the diagonal distance from the nosing of your top step to the nosing of your bottom step. The nosing is the front edge of each tread, the part that overhangs the step below. You will also hear this called the slope length or the nosing line.

This is the number every custom handrail is built from, and it matters because it is longer than both the height of your stairs and their horizontal depth. Measuring the wall instead is the single most common reason a rail arrives too short.

The simplest method: hold a tape measure flat along the stair slope from the bottom nosing to the top nosing. Keep it straight and taut.

If you cannot get a clean diagonal: measure the total run (horizontal, face of bottom riser to face of top riser) and the total rise (vertical), then calculate. Slope length = square root of (run² + rise²). For a staircase with a 10-foot run and 8-foot rise, the slope length is about 12.8 feet.

2. Add Your Extensions

A handrail that stops exactly at the first and last step leaves you without support at the two moments you most need it — stepping on and stepping off.

Add 6 to 12 inches beyond the nosing at each end. A simple rule if you want one number: add 12 inches total to your nose-to-nose measurement, giving 6 inches at each end.

Commercial and ADA-governed installations have stricter requirements, typically a full 12-inch horizontal extension at the top and one tread depth plus 12 inches at the bottom. See our ADA requirements guide if your project needs to comply.

3. Check Your Wall

Measure the usable wall length along the stair run. If your calculated handrail is longer than the available wall, trim your extensions rather than discovering the problem at install time. Keep the rail at least 2 inches shorter than the wall so it does not overrun the edge.

4. Determine Handrail Height

Measure vertically from the stair nosing to where you want the top of the rail. Building code requires 34 to 38 inches. Most people find 36 inches the most comfortable height.

Mark your chosen height at both the bottom and top step, then snap a chalk line between the marks. That line is where your brackets go — and checking it before you order tells you whether the rail will clear any obstructions along the way.

5. Count Your Brackets

Every handrail we build ships with the correct number of brackets for its length, so you do not need to order these separately. For reference:

• 12" to 60" (1–5 ft) → 2 brackets
• 61" to 96" (5–8 ft) → 3 brackets
• 97" to 144" (8–12 ft) → 4 brackets
• 145" to 180" (12–15 ft) → 5 brackets
• 181" to 216" (15–18 ft) → 6 brackets
• 217" to 276" (18–23 ft) → 7 brackets

Wherever possible, land brackets on wall studs. More detail on placement and mounting without studs is in our bracket guide, or browse handrail brackets if you are replacing hardware on an existing rail.

Measuring for a Ground-Mounted Handrail

1. Count Your Steps

Count the number of stair risers (vertical faces). This determines which product size you need. Our single post handrails are designed for 1-3 steps. For longer runs, our ground-mounted railing systems accommodate any stairway length.

2. Measure Step Width

Measure the total width of your stairway. For a single handrail on one side, you only need one railing. For railings on both sides, order two. If the stairs are wider than 44 inches, building code may require a handrail on both sides.

3. Check the Landing

If your stairs have a landing or platform at the top, measure the landing depth. You may need a separate guardrail section for the landing — our assembled railing systems include both stair and level sections.

4. Check Step Consistency

Concrete steps are rarely perfectly even. Measure the rise of each individual step, not just the total. If they vary by more than about a quarter inch, mention it when you order — it affects how the posts are set.

Measuring for Guardrails and Deck Railings

For level guardrails (decks, balconies, landings):

• Measure the total linear footage of railing needed
• Guardrails must be a minimum of 42 inches tall (different from stair handrails at 34-38")
• Account for corner posts if the railing turns 90 degrees
• Measure each straight section separately — railings are cut to length per section

See our building code guide for when a guardrail is required rather than a handrail.

Common Measuring Mistakes

• Measuring the wall instead of nose to nose: the wall is horizontal, your rail is diagonal. Different numbers.
• Forgetting extensions: a rail that ends at the last step is short by a foot or more in practice.
• Measuring only one end: older homes settle. Check your height at both the top and bottom step. If they differ, your stairs are not square and bracket placement needs to account for it.
• Not checking for plumb: old houses can have walls that lean. Use a level to verify before drilling brackets.
• Ignoring obstructions: check for light switches, outlets, or trim that might interfere with bracket placement.
• Rounding down: if you are between sizes, go longer. A rail can be trimmed. It cannot be lengthened.

Still Not Sure? We Can Help

Send us your stairway measurements and a few photos and we will recommend the exact products and quantities you need. Contact us here — we respond the same day.

Every handrail we build is cut to the length you specify rather than sold in fixed kit sizes, so there is no rounding to the nearest stock size.