Fall Clearance Calculator
For a lanyard with an energy absorber. Enter your equipment’s figures from the manufacturer’s instructions; the defaults are typical examples only. All distances in metres.
Clearance needed below the surface = lanyard length + energy absorber extension + harness stretch + D-ring height − anchor height + safety margin. Free fall = lanyard length + D-ring height − anchor height. This does not account for swing falls, structures you could strike on the way down, or rescue. Always follow the equipment manufacturer’s clearance requirements.
Frequently asked questions
What is fall clearance?
Fall clearance is the distance needed below the working surface for a fall arrest system to stop a falling person before they strike the ground or an obstruction. It adds up the free fall, the extension of the energy absorber, harness stretch, the height of the person and a safety margin.
Why does anchor position matter so much?
An anchor above your head limits free fall and the total fall distance. An anchor at foot level can more than double the free fall, which increases the forces on the body and the clearance needed. Anchor as high as practical.
What values should I use?
Use the figures from the manufacturer of your specific lanyard, energy absorber and harness. The defaults in this calculator are typical example values only. Where clearance is tight, consider a self-retracting lifeline, a shorter lanyard, a higher anchor, or a restraint system that prevents the fall altogether.
Does this include swing falls?
No. If the anchor is not directly above you, a fall will swing sideways and may strike nearby structures, and the vertical drop can also increase. Keep the anchor as close to directly overhead as possible.