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Lifting Index Calculator

Work out lifting index instantly with clear inputs, formula shown and shareable results.

About Lifting Index Calculator

The lifting index is load weight divided by the recommended weight limit. An index at or below one is considered safe for nearly all healthy workers; above three the task carries a high risk of low back injury for most people. Increasing frequency reduces the recommended limit sharply, so the frequency-adjusted index is often the one that matters.

Formulas

Lifting index

LI = load weight / recommended weight limit

Frequency multiplier

About 0.94 at 1 lift/min, 0.84 at 4, 0.52 at 9 and 0.28 at 12

Worked example

With the default values below, Lifting Index Calculator returns Lifting index of 1.500. Change any input above and every figure here is recalculated in your browser.

Inputs used

Weight of the loadminimum 0.1 kg
18 kg
Recommended weight limitminimum 0.1 kg
12 kg
Lifting frequencyminimum 0.1 lifts/min
2 lifts/min

Results

Lifting index
1.500
Risk category
Increased risk — redesign recommended
Weight that would give an index of 1
12.00 kg
Index adjusted for frequency
1.786

Step by step

  1. 1Values used
  2. 2Lifting index
  3. 3Frequency multiplier
  4. 4Lifting index= 1.500
  5. 5Risk category= Increased risk — redesign recommended
  6. 6Weight that would give an index of 1= 12.00 kg
  7. 7Index adjusted for frequency= 1.786

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation or tax into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Preliminary estimate only. Manual handling risk assessment should be carried out by a competent ergonomist using the full NIOSH method.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Preliminary estimate only. Manual handling risk assessment should be carried out by a competent ergonomist using the full NIOSH method.

Frequently Asked Questions

How is the Lifting Index figure worked out?

LI = load weight / recommended weight limit. The lifting index is load weight divided by the recommended weight limit.

What does an index above three mean in practice?

That the task should be engineered out: mechanical aids, load splitting, or changing the layout so the reach and height multipliers improve. Training alone does not reduce a high lifting index.

What values do I need to enter?

This calculator takes 3 inputs: Weight of the load, Recommended weight limit, Lifting frequency. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.

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