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Calcimator

Fall Factor Calculator

Calculate the fall factor from fall distance and rope paid out. Estimate impact force and severity rating to understand climbing fall dynamics.

Inputs

ft
ft

Results

Fall Factor

0.5

Estimated Impact Force

2.54 kN

Severity RatingModerate
Fall Energy3,139 J
How to Use This Calculator
  1. Enter the total fall distance in meters — this is from the climber's position to where the rope becomes taut, including slack above the last piece.
  2. Input the rope paid out in meters — the length of rope between the belayer and climber at the moment of the fall.
  3. Read the Fall Factor (0–2): values below 0.3 are low-severity; above 1.0 are serious or critical.
  4. Check Estimated Impact Force in kN — values above 9 kN approach the UIAA limit for anchors and gear.
  5. Use the Severity Rating (Low / Moderate / Serious / Severe / Critical) to evaluate risk before committing to a route.
  6. Review Fall Energy in Joules to understand the dynamic loading your rope must absorb.

How the result changes with Rope Paid Out

Rope Paid OutFall FactorEstimated Impact Force
8.090.492.52 kN
280.141.69 kN
520.081.61 kN
720.061.59 kN

What each input means

Fall Distance
Total distance the climber falls before the rope begins to catch. Includes slack and distance above last protection.
Rope Paid Out
Length of rope between the belayer and the climber at the moment of the fall. More rope means lower fall factor.

What each result means

Fall Factor
Ratio of fall distance to rope paid out. Ranges from 0 to 2. Higher values produce greater impact forces.
Estimated Impact Force
Estimated peak force on the climber assuming 80 kg body weight and a standard dynamic rope.
Severity Rating
Qualitative severity: Low (≤0.3), Moderate (≤0.7), Serious (≤1.0), Severe (≤1.5), Critical (>1.5).
Fall Energy
Gravitational potential energy converted during the fall (mass × gravity × fall distance).

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    Fall Distance = 4, Rope Paid Out = 8 = 2 input(s) provided
  2. Calculate Fall Factor
    Fall Factor = ff
    0.5 = 0.5
  3. Calculate Estimated Impact Force
    Estimated Impact Force = round((force / 1000) * 100) / 100
    2.54 = 2.54
  4. Calculate Severity Rating
    Moderate = Moderate
  5. Calculate Fall Energy
    Fall Energy
    3139 = 3139

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.

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