Fall Clearance Distance Calculator
Formula Reference
Free Fall Distance = Lanyard Length − Anchor Position Offset (relative to D-ring)Total Required Clearance = Free Fall Distance + Deceleration Distance + Harness Stretch + Height Below D-Ring + Safety Factor
Pass condition: Available Clearance ≥ Total Required Clearance
Key Regulatory Limits
| Maximum free fall (standard) | 6 ft — OSHA 29 CFR 1926.502(d)(16)(ii) |
| Maximum deceleration distance | 3.5 ft (42 in) — OSHA/ANSI Z359.1, shock-absorbing lanyards |
| Maximum harness stretch (test) | ~18 in — ANSI Z359.11 |
Methodology, interpretation & sources
Purpose. Calculates the minimum vertical clearance required below a work surface for a personal fall arrest system to stop a fall before the worker contacts a lower level, per OSHA 29 CFR 1926.502 and ANSI Z359 .
How to use the result. Start with source data you can verify, enter values on a consistent unit and time basis, and record the assumptions used. The main inputs on this page include Lanyard / Connecting Device Length (ft), Anchor Position vs. D-Ring (ft) Positive if anchor is ABOVE the D-ring (typical overhead tie-off); negative if BELOW (e.g., foot-level tie-off)., Connecting Device Type Sets a typical default deceleration distance — always confirm against your specific device's rating., Deceleration Distance (ft), Harness Stretch (ft) Typical assumption: 1 ft (up to 1.5 ft max per ANSI Z359.11 testing)., Height Below D-Ring (ft) D-ring to feet while hanging in the harness. Typical average: 5 ft.. Re-run the calculation when those assumptions change rather than carrying an old result forward.
Decision use. Use this tool as a planning estimate and confirm the final control or design with a competent person using site measurements, manufacturer data and applicable construction requirements.
Limitations. Ground conditions, equipment configuration, dynamic loading, access, weather and work sequencing can materially change the safe limit.
Primary references. Use the current edition/version that applies to your jurisdiction and organization:
Editorial note. Prepared and maintained by Impact Tech Solutions. Editorially updated 28 September 2026. No individual professional credential is claimed on this page; high-consequence, statutory, tax, engineering or health decisions should be independently verified against the current primary source and, where required, a qualified professional.