ergonomics · Free · Open Source · MIT

NIOSH Lifting Calculator

Recommended Weight Limit + Lifting Index. Based on NIOSH Publication 94-110. Results shown with the full formula so you can verify. Zero signup, zero tracking, zero data sent to a server — all calculation is client-side.

Inputs

Horizontal distance H (cm)

Vertical origin V (cm)

Vertical travel D (cm)

Asymmetry angle A (°)

Frequency (lifts/min)

Duration (hours)

Grip / coupling

Actual load (kg)

NIOSH Lifting Equation · INCREASED

Recommended Weight Limit

11.3 kg

Lifting Index

1.32

Raw JSON result

{
  "rwl": 11.3,
  "li": 1.32,
  "risk": "increased"
}

Overview

About the NIOSH Lifting Calculator

NIOSH Revised Lifting Equation (1994) computes Recommended Weight Limit (RWL) and Lifting Index (LI) for manual lifting tasks. It's the most widely used ergonomic assessment for manual handling in the US and internationally. Based on 6 multipliers — horizontal distance, vertical origin, vertical travel, asymmetry angle, frequency, coupling.

Used in OSHA ergonomic citations (General Duty Clause), NIOSH research, HSE UK alternative to the MAC tool, and virtually every academic manual-handling study since 1994.

Formula

RWL = LC × HM × VM × DM × AM × FM × CM; LI = Load / RWL

Regulation

NIOSH Publication 94-110

How to use

Step-by-step: using the NIOSH Lifting Calculator

1
Measure horizontal distance H (cm) from ankles to hand position at lift origin.
2
Measure vertical origin V (cm) — hand height from floor at lift start.
3
Measure vertical travel D (cm) — total up/down distance of the lift.
4
Estimate asymmetry angle A (degrees) — twist required.
5
Estimate frequency F (lifts/minute) and duration hours.
6
Select coupling quality (grip condition).
7
Enter actual load kg.

Worked examples

NIOSH Lifting Calculator — real-world examples

Warehouse picker

H=30cm, V=75cm, D=50cm, A=0°, F=2/min, 4-hour duration, good grip, 15kg load. RWL computes to roughly 15kg; LI ≈ 1.0. At the acceptable threshold — but any increase in frequency or load pushes this past increased risk.

Who uses this calculator

Used by safety professionals worldwide

●Ergonomics consultants
●Warehouse and logistics HSE teams
●Healthcare patient-handling programs (nurses, aides)
●Manufacturing assembly-line designers
●OSHA General Duty Clause investigations

Watch out for

Common mistakes when calculating niosh lifting calculator

⚠Using the Lifting Index as a pass/fail. LI ≤ 1.0 means 'most workers can do this safely'; LI > 3 means 'most workers CANNOT do this safely'. The 1-3 range requires case-by-case judgement.
⚠Ignoring frequency multiplier adjustments for long-duration tasks (>2 hours).
⚠Applying NIOSH equation to lifts with significant carrying or pushing components. NIOSH is for lifting only.

FAQ

Frequently asked questions

What is the Lifting Index (LI)?+

LI = Load / RWL. LI ≤ 1.0 acceptable for most workers. LI > 3.0 high risk for most workers.

Regulation citations

Authoritative sources

Related calculators

More free HSE calculators

Manual Handling MAC Calculator

HSE UK Manual Assessment Charts

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Free for any website, blog, or course — MIT / CC BY 4.0. Attribution stays visible.

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