NLE Calc: A Mobile Application Based on the Revised NIOSH Lifting Equation

Posted on by Emily Warner, MA, Stephen D. Hudock, PhD, CSP, and Jack Lu, PhD, CPE


Knowing how much weight an individual worker can safely lift is a key component to preventing back injury in the workplace. NIOSH recently released a free mobile lifting application, NLE Calc, which helps users determine safe lifting limits. The new NIOSH app takes information from the internationally renowned “Revised NIOSH Lifting Equation” out of the laboratory and into the hands of workers and employers.

What is NLE Calc?

The NIOSH Lifting Equation Calculator app (NLE Calc) allows users to quickly calculate manual lifting risks as they occur on the job. NLE Calc even uses the composite lifting index (CLI)—often ignored by commercially available apps—to calculate manual lifting risks for multiple and complex lifting tasks. Workers, employers, and occupational health professionals can easily download NLE Calc from Apple iTunes or Google Play, type the indicated measurements into the equation, and use the results to help identify ergonomic solutions for reducing the physical stresses associated with manual lifting.

What are the key benefits of using NLE Calc?

  • Calculates the composite lifting index (CLI) for multiple lifting tasks (often ignored by most commercial apps)
  • Uses equations approved by NIOSH ergonomists, who created the NIOSH Lifting Equation (NLE)
  • Promotes better musculoskeletal health
  • Raises workers’ awareness about their job tasks
  • Helps workers and employers make informed decisions about potential musculoskeletal hazards
  • Serves as job design guidelines for manual lifting tasks
  • Can be used as a research tool to collect manual lifting data


NIOSH recommends that single or multiple lifting tasks have a (composite) lifting index lower than 1.0.

With the app’s release, NIOSH added a page on our website specifically dedicated to NLE Calc. This webpage offers more information on how to use the app and how to interpret the results.

The cost of musculoskeletal disorders is a serious health concern. Around the world, musculoskeletal disorders are responsible for roughly 21% of the years people live with disabilities.1 In 2010, low back pain and neck pain were among the top five leading causes of disability worldwide. 1 In the United States and Canada, more people are unable to work because of musculoskeletal disorders than because of any other group of diseases.2

For over 20 years, the Revised NIOSH Lifting Equation has been the international standard for assessing risks associated with lifting tasks, preventing the onset of lower back pain, and reducing work-related musculoskeletal disorders. As you use the app, please tell us about your experience in the comment section below. We would also appreciate your help in getting the word out about the app.


Emily Warner, MA, is an ORISE Fellow in the NIOSH Division of Applied Research and Technology.

Stephen D. Hudock, PhD, CSP, is Manager of the NIOSH Musculoskeletal Health Cross-Sector.

Jack Lu, PhD, CPE, is a Research Ergonomist in the NIOSH Division of Applied Research and Technology.


1 Hoy DG, Smith E, Cross M, Sanchez-Riera L, Blyth FM, Buchbinder R, Woolf AD, Driscoll T, Brooks P, March LM. [2015] Reflecting on the global burden of musculoskeletal conditions: lessons learnt from the Global Burden of Disease 2010 Study and the next steps forward. Ann Rheun Di; 74:4-7.

2 Punnett L, Pruss-Ustun A, Nelson DI, Fingerhut MA, Leigh J, Tak S, Phillips S. [2005]. Estimating the Global Burden of Low Back Pain Attributable to Combined Occupational Exposures. AJIM; 48: 459-469.


Posted on by Emily Warner, MA, Stephen D. Hudock, PhD, CSP, and Jack Lu, PhD, CPE

21 comments on “NLE Calc: A Mobile Application Based on the Revised NIOSH Lifting Equation”

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    I have a question regarding the calculation of the horizontal location (H) for inputs into the model. I have a lifting task, where individuals are lifting sledge hammers off a line, the center of gravity of the load/lift is to the left of the left hand, so outside the area between the two hands, and the sledgehammer is being lifted with two hands. In the application manual it states to measure from the mid-point of the line joining the inner ankle bones (no problem here) to a point projected on the floor directly below the mid-point of the hand grasps (i.e. load center). The grey area to me is the “load center” is the load center the center between where the load is being handled, mid-point between the two hands, or in this instance, is the load center the center of gravity which is to the left of the left hand – the distances are not similar! For further clarification on the H measurement, I’m assuming it the total distance between the two points and not the horizontal distance projected out in front of the torso!

    Any clarification on these two points would be appreciated

    The NIOSH lifting equation is not designed to be used when the center of the load is not symmetrical. In your lifting condition the center of the load/gravity is located near the left hand and the asymmetry line for this lift would be off center creating additional risk to the low back. Also, the “true” H for this lift should be measured from the center of the load projected on the horizontal plane (i.e., ground) to the center of the two ankles (on the ground plane as well). In this case, the true H would be greater than the H measured by definition. I do not recommend using NLE for this lifting condition. If this lift is not frequently performed, a biomechanical model such as the U of Michigan’s 3DSSPP is a good assessment tool.

    Hope the info helps.

    I really appreciate the good quality content you are posting here for free. It’s really interesting site. Here we develop the Mobile and web applications

    Consultation on the criteria used to establish the levels of risk in the manual lifting of loads.
    In the NLE-calculator app, why is a moderate risk level (yellow) considered in case the wash index is between 1 and 2?
    Why is a red risk level considered in case the survey index is greater than 2?

    Please indicate where to find this reference.

    NIOSH has published an article to summarize the threshold levels for the (composite) lifting index (LI or CLI) from 13 studies. The studies supported the value of the LI or CLI = 1.0 as the safe guidance. The info on the article is below:

    Lu M., Putz-Anderson V., Garg A. and Davis K.: Evaluation of the impact of the revised NIOSH lifting equation. Human Factors. 58 (5):667-82 (2016)

    The app was designed to work on most Android and iOS devices. If you are unable to operate the app on your Samsung phone, please share specific details regarding the issue you are experiencing.

    How do I clear out the “Saved Jobs Folder” after I’m finished with the data? Can seem to figure this out.

    Thank you for your question.
    On iPhone or iPad: Swipe left on the job to reveal delete button.
    On Android: Tap and hold on job to reveal context menu. Click delete. It’s usually located at the top of the screen.

    The print and email functions for results of the NLE Calc is currently under development and will be available in a later version.

    I have a bunch of jobs in the saved jobs folder. I want to calculate the CLI using most of the jobs listed in the folder. I don’t see how to select them and tell the app to calculate it. I’m using an Android tablet.

    Or…perhaps I have to delete the jobs in that folder that I don’t want to be included.
    I open each job and find the LI but how do I tell the app to calculate the CLI?

    Thanks for your help.

    The “exporting of saved tasks” feature for the NLE Calc is being developed. This function will be available in version 2.0 that is planned to be published in 2020.

    Attempted to download the NLE Calc App from the Play Store and received an error message that it’s not compatible with the latest version of Android.

    I still get the error with android 13.
    Is there an update on the download of the NLE Calc App from Google Play Store?
    When is the update expected to be launched?

    the Google play store does not find the application today. Where can I find it to download it please?
    Many thanks

    Unfortunately, the app is not currently available on the Google Play store for Android phones; it is available on iOS for Apple phones but is an older version. NIOSH is currently in the process of updating the app for Android and iOS and expects the update to be available later this year.

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Page last reviewed: April 25, 2023
Page last updated: April 25, 2023