Rope Stretch Calculator
Calculate fall factor, rope stretch percentage, and impact force for climbing falls.
How to Use the Rope Stretch Calculator
- Enter the rope length paid out in meters.
- Enter the fall distance in meters.
- Enter the climber's weight in kilograms.
- Select the rope type: dynamic or static.
- Click Calculate to see fall factor, stretch percentage, and impact force.
Use Cases
- •Understanding the physics of climbing falls for safety education.
- •Comparing dynamic vs static rope behavior under load.
- •Anchor and gear force analysis for climbing instructors.
Formula
Formula: Fall factor = fall distance / rope length. Stretch % = base stretch + fall factor × 8 (dynamic) or × 0.5 (static). Impact force ≈ weight × g × √(2 × fall factor / stretch fraction) / 1000 kN.
Frequently Asked Questions
What is fall factor in climbing?
Fall factor is the ratio of fall distance to rope length paid out. A fall factor of 2 is the maximum possible (leader falls past the belay). Higher fall factors mean harder falls.
Why do dynamic ropes stretch?
Dynamic ropes are designed to elongate 28–40% to absorb the energy of a fall, reducing the peak force transmitted to the climber, protection, and belayer.
Can I use a static rope for lead climbing?
No. Static ropes stretch only 2–3% and transmit much higher forces in a fall, exceeding safe limits for the climber and anchor. They are for fixed lines and hauling only.