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The ladder's extended working length, measured along the ladder itself.
This is the length along the ladder's rails from its base to its top support point, not the vertical height it reaches — used together with the base distance to check OSHA's 4:1 setup ratio.
The horizontal distance from the base of the ladder to the wall or support it leans against.
Per OSHA 29 CFR 1926.1053(b)(5)(i), this should be approximately one-quarter of the ladder's working length — too short an angle risks the ladder sliding out at the base; too steep an angle risks tipping over backward.
How far the ladder's side rails extend above the upper landing surface, when used for access to that landing.
Per OSHA 29 CFR 1926.1053(b)(1), when a ladder is used to access an upper landing surface, its side rails must extend at least 3 feet (0.9144 m) above that landing surface, giving a secure handhold while stepping on or off.
Base-distance-to-working-length ratio
4 :1 (target 4:1)
This restates OSHA 29 CFR 1926.1053's fixed setup-angle (4:1, ~75.5°) and landing-extension (3 ft / 0.9 m minimum) rules only. It does not check ladder duty rating/load capacity, the condition of the ladder or the surface it rests on, tie-off/securing requirements, or overall fall protection needs for the specific task — those must be verified separately by the user each time the ladder is set up.
- Resulting ladder angle from horizontal
- 75.52 °(target ~75.5°)
- Landing extension
- 3.5 ft (OSHA min 3 ft)
They open the calculator with your figures already in it
Extension Ladder Setup Angle & Placement Safety Checker: 4 :1 (target 4:1) — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Per OSHA 29 CFR 1926.1053(b)(5)(i) (verified against the regulatory text): 'Non-self-supporting ladders shall be used at an angle such that the horizontal distance from the top support to the foot of the ladder is approximately one-quarter of the working length of the ladder' — the standard 4:1 ratio, corresponding to a ladder angle of approximately 75.5° from horizontal. Per 1926.1053(b)(1) (verified): when used for access to an upper landing surface, 'the ladder side rails shall extend at least 3 feet (.9 m) above the upper landing surface.'
Inputs used
- Ladder Working Length (Along the Ladder)
- 26 ft
- Horizontal Distance from Wall/Support to Ladder Base
- 6.5 ft
- Ladder Side Rail Extension Above Landing
- 3.5 ft
Intermediate steps
- Resulting ladder angle from horizontal
- 75.52 °(target ~75.5°)
- Landing extension
- 3.5 ft (OSHA min 3 ft)
Confidence note: This restates OSHA 29 CFR 1926.1053's fixed setup-angle (4:1, ~75.5°) and landing-extension (3 ft / 0.9 m minimum) rules only. It does not check ladder duty rating/load capacity, the condition of the ladder or the surface it rests on, tie-off/securing requirements, or overall fall protection needs for the specific task — those must be verified separately by the user each time the ladder is set up.
What this calculation does not cover
- Says nothing about what the ladder is near. An aluminum ladder raised into an overhead service drop does not have to touch it to flash over, and the rule is a clearance distance from energized conductors plus a non-conductive ladder for work on or near live equipment — neither of which any setup angle can satisfy. That clearance is judged before the ladder goes up, not after it is angled.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- Per OSHA 29 CFR 1926.1053(b)(5)(i) (verified against the regulatory text): 'Non-self-supporting ladders shall be used at an angle such that the horizontal distance from the top support to the foot of the ladder is approximately one-quarter of the working length of the ladder' — the standard 4:1 ratio, corresponding to a ladder angle of approximately 75.5° from horizontal. Per 1926.1053(b)(1) (verified): when used for access to an upper landing surface, 'the ladder side rails shall extend at least 3 feet (.9 m) above the upper landing surface.'
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