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Rise × run

7.5″ rise × 10.5″ run stairs

What a 7.5-inch riser paired with a 10.5-inch tread actually gives you — pitch, comfort, and code status — plus the calculator to size a full flight.

Pitch
35.5°
Blondel 2R+T
25.5in
Comfort
Ideal

Code status

A 7.5-inch riser with a 10.5-inch tread is compliant under IRC 2021 (max riser 7.75″, min tread 10.0″), and non-compliant under the IBC commercial standard (max riser 7.0″, min tread 11.0″).

The numbers

pitch = atan(7.5 / 10.5) = 35.5°
Blondel = 2 × 7.5 + 10.5 = 25.5″ (ideal ≈ 24–25)

This pair is one step's geometry. To size a complete flight for your floor-to-floor height, enter your total rise in the calculator and it will hold the riser near 7.5″ while checking every code limit.

Size a full flight

What this combination is like to use

A 7.5-inch riser with a 10.5-inch tread produces a 35.5-degree pitch, which is on the brisk side of comfortable for a staircase. In practice that means it is efficient with floor space while staying easy to use. Its Blondel value of 25.5 inches sits just above the 24–25 inch Blondel band — a touch tall in the step, but still comfortable.

Across a typical flight of about 14 treads, the 10.5-inch tread depth works out to roughly 11.4 feet of horizontal run — a moderate footprint. It is fine for a residential stair under the IRC but would fail an IBC commercial plan review because its 7.5-inch riser exceeds the IBC's 7-inch cap and its 10.5-inch tread is below the IBC's 11-inch minimum.

When to choose it

This is a sound general-purpose main-stair pairing: comfortable to climb yet reasonably efficient with floor space. Whatever your floor-to-floor height, the calculator below will hold the riser near 7.5 inches, divide the rise into uniform steps, and check the result against the code you select.

Nearby combinations

7″ × 12″, 8.25″ × 9″, 6″ × 12″, 6.75″ × 11″