100 kg x 5 reps
- Epley
- 116.666666667 kg
- Brzycki
- 112.5 kg
- Training range 80%
- 93.3333333333 kg
One Rep Max Calculator
Use this free one rep max calculator to estimate 1RM with Epley and Brzycki formulas for strength training.
Estimate, not diagnosis Formula notes Example inputs Tab-only history
Formula steps
- Use the lifted weight and reps completed.
- Epley estimate = weight x (1 + reps / 30).
- Brzycki gives a second estimate for comparison.
How to use the One Rep Max Calculator
- Enter the requested measurements, dates, lab values, or workout details.
- Check that the units and formula assumptions match what the tool is asking for.
- Press the calculate button to see the answer, supporting metrics, and formula steps.
- Read the estimate with the health disclaimer in mind, then copy the result if you need it for notes.
What people use it for
Estimate a one-rep max without testing a true max.
Compare Epley and Brzycki estimates.
Plan training percentages from a recent rep set.
Track strength changes over time.
Quick examples
Bench example
100 kg x 5Estimated 1RM about 117 kg
Squat example
140 kg x 3Estimated 1RM about 154 kg
Volume set
60 kg x 8Estimated 1RM about 76 kg
Need the guide or a nearby tool?
Need a slower walkthrough, a related calculator, or the full library? These links keep you close to the task you started.
- How to use the One Rep Max Calculator See slower examples, input meanings, formula notes, result limits, and mistakes to avoid.
- Health & Fitness Browse related calculators and utilities in the same category.
- Calculator and utility guides Find more guides that use real tool inputs and example numbers.
- All free tools Search every live tool, converter, calculator, AI helper, and browser utility.
Frequently asked questions
Plain-language answers about when to use the estimate, what the formula means, what it cannot decide for you, and how privacy works.
When should I use the One Rep Max Calculator?
Use it for simple educational checks, trend tracking, or planning tasks like these: Estimate a one-rep max without testing a true max. Compare Epley and Brzycki estimates. It can help you understand a number, but it cannot explain your whole health situation.
What do the main One Rep Max Calculator inputs mean?
Enter the body, activity, date, or lab values exactly in the units shown on the page. Height, weight, age, sex, time, and activity level can change health estimates a lot, so treat each label like a rule instead of a suggestion. If you are unsure which option fits, choose the closest honest match and read the result as a rough estimate.
What is the One Rep Max Calculator doing with my inputs?
In plain language: The main estimate uses Epley: one-rep max = weight x (1 + reps / 30). Brzycki is shown as a comparison. Read the result together with the notes on the page, because health and fitness numbers often need personal context.
How should I read the One Rep Max Calculator result?
Use the result as a learning number, not a final answer about your body or health. The supporting lines can show categories, ranges, calories, dates, or targets, but those numbers still need context like age, medical history, pregnancy status, training level, and advice from a qualified professional.
Can I use this as medical advice?
This is training math, not a safety guarantee. Do not attempt heavy max lifts without appropriate technique, equipment, and supervision. Use the calculator as a learning tool, then ask a qualified professional about decisions that affect care, pregnancy, medication, nutrition, or safety.
What should I double-check before trusting the result?
Check the units, date, and personal details before reading the answer. For example, pounds and kilograms, inches and centimeters, or a wrong activity level can change the result quickly. If the number feels surprising, rerun it slowly and compare it with the examples.
Does the site save my health inputs?
No. The calculator runs in your browser tab. Recent answers stay only on the page while you use it, and they are not sent to a server.