Ladder Safe Angle (4:1 Rule)

For every 4 ft of height, base is 1 ft from wall. Angle ≈ 75.5°.

Inputs

Result

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How to use this calculator

  • Enter ladder length.

About this calculator

OSHA-recommended ladder placement: 4:1 ratio. For every 4 ft of vertical height, 1 ft of horizontal base distance. Equivalent angle: arctan(4) ≈ 75.96° from horizontal. Too steep: tips backward. Too shallow: slides out. Top should extend 3 ft above landing for grip. Verify ladder is on stable ground + tied off where possible. Source: OSHA 1926.1053.

Frequently asked

Why 4:1?+
Standard safety guideline. Steep enough ladder doesn't slide; not so steep it tips back.
OSHA requirement?+
Recommended best practice. Some industries / state codes formalize. Most manufacturers stamp 75° on ladder.
How do I check?+
Stand at base with toes touching feet. Arms straight out — should reach the rung at shoulder height.
Extension above landing?+
3 ft minimum. Provides handhold for safe transition on/off ladder.
Don't do?+
Top three rungs. Lean to side (move ladder). Soft ground. Climb ungear-loaded.

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Informed consent for human-subjects research compliant with 45 CFR § 46.116 (Revised Common Rule, 2018) — includes key information section, risks/benefits, IRB contacts.