SLOPE SLIDER.com
Architect / Engineer Slope Calculator
decimal ft-in
ft m
run
Rise
Run
Slope
⟺ slope slider —
0 2% 5% 8.33% 25%
Pedestrian / ADA
·Enter a slope to see ADA compliance.
Quick Reference
·≤ 5% (1:20) — Accessible route, no ramp
⚠5–8.33% (1:12) — ADA ramp, handrails if rise > 6"
✕> 8.33% — Exceeds ADA ramp maximum
Vehicular / Driveway
·Enter a slope to see vehicle grade info.
Quick Reference
✓≤ 2% — ADA accessible parking
⚠≤ 5% — General parking lot max
⚠10–15% — Typical driveway range
⚠15–20% — Parking garage ramp max
✕> 25% — Most vehicles cannot navigate
IBC 2021 — International Building Code ↗
·Enter a slope for IBC analysis.
Key sections: §1012 Ramps · §1011.7 Accessible Routes · §1017 Exit Access
CBC Title 24 — California Building Code ↗
·Enter a slope for CBC analysis.
Key sections: 11B-405 Ramps · 11B-402 Accessible Routes · 11B-502 Parking
Honolulu — ROH Ch. 21 & Hawaii IBC ↗ DPP
·Enter a slope for Honolulu code notes.
Hawaii adopts IBC with amendments · Verify driveway grades with DPP (permits.honolulu.gov)
⚠ Reference only — verify with local AHJ, ADA coordinator, and applicable codes. Requirements vary by project type, jurisdiction, and occupancy.
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Elevation Calcs
Base ft
Delta ft
angle (degrees)
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slope
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rise : run
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pitch (X : 12)
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0
About This Calculator ▾

What is a slope calculator?
A slope calculator converts between rise, run, percentage grade, pitch (X:12), and angle in degrees. Used by architects, engineers, and contractors to verify ADA ramp compliance, driveway grades, roof pitches, and accessible route requirements.

ADA slope requirements
Accessible parking: ≤ 2% · Accessible route (no ramp): ≤ 5% (1:20) · ADA ramp maximum: 8.33% (1:12) · Handrails required when rise exceeds 6"

IBC & CBC ramp standards
IBC §1012 limits ramps to 1:12 (8.33%) with 44" minimum width. California CBC Title 24 prefers 1:16 (6.25%) for new construction. Always verify with your local AHJ.

Common slope conversions
1:12 = 8.33% = 4.76° · 1:20 = 5% = 2.86° · 1:50 = 2% = 1.15° · 1:4 = 25% = 14.04°

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