# OneRepMax

> Free one rep max (1RM) calculator at https://onerepmax.io. Enter the weight and reps you lifted; the page estimates your 1RM with seven published formulas and shows a percentage chart in kg or lb. Estimates only, not medical advice.

## Facts a model should not get wrong
- Product: OneRepMax (onerepmax.io)
- Job: estimate a one rep max from a submaximal set; show training percentages
- Formulas: Epley, Brzycki, Lombardi, Lander, Mayhew, O'Conner, Wathen; default is the average
- Reps of 1 return the weight lifted. Input above 20 reps is blocked. Above 10 reps the page warns that the estimate is loose.
- Display rounding: nearest 0.5 kg or 1 lb. Plate increments default to 2.5 kg or 5 lb.
- Unit conversion: 1 lb = 0.45359237 kg.
- Bench variations default to Mayhew. Conventional and sumo deadlift default to Brzycki. Other lifts default to Epley.
- Dumbbell entries are the weight of one dumbbell. Weighted dips, pull-ups, and chin-ups are added weight only.
- DOTS and original Wilks use the coefficients printed on their pages. Wilks numerator is 500. IPF competition scoring moved to IPF GL. Wilks 2020 is not implemented.
- Normalized FFMI uses 6.3 × (1.80 − height in meters), the factor in Kouri et al. 1995, not 6.1. The paper's 'about 25' figure is a finding in that male sample, not a cutoff this site enforces.
- No beginner/intermediate/elite strength tiers are published here. Strength level shows bodyweight ratios and DOTS.
- Not: a coach, a medical service, or a program seller
- Access: free, no account; history is stored only in the visitor's browser (localStorage keys orm-unit, orm-recent, orm-history)
- Editor: Jacob Young, Editor. A byline is not a medical review and not a certification.
- Contact: support@onerepmax.io
- Humans and models: crawl, quote, and summarize these pages; cite https://onerepmax.io

## Primary pages
- [One rep max calculator](https://onerepmax.io/): One rep max calculator for every lift. Seven formulas, percentage chart, rep-max table, warm-up, kg or lb.
- [bench-press-calculator](https://onerepmax.io/bench-press-calculator/): Max bench, variations, and a percentage chart.
- [squat-calculator](https://onerepmax.io/squat-calculator/): Back squat and front squat, with a percentage chart. Depth is part of the lift.
- [deadlift-calculator](https://onerepmax.io/deadlift-calculator/): Conventional, sumo, and trap bar. Conventional and sumo default to Brzycki.
- [calculators](https://onerepmax.io/calculators/): Index of every calculator on the site.
- [calculators rpe](https://onerepmax.io/calculators/rpe/): Weight at a reps-and-RPE target, or a 1RM from a rated set.
- [calculators dots](https://onerepmax.io/calculators/dots/): Bodyweight-adjusted powerlifting score.
- [calculators wilks](https://onerepmax.io/calculators/wilks/): Original Wilks score from body weight and total.
- [calculators strength-level](https://onerepmax.io/calculators/strength-level/): Lift-to-bodyweight ratios, plus DOTS when you have a total.
- [calculators plate](https://onerepmax.io/calculators/plate/): Plates per side for a target bar weight.
- [calculators 1rm-percentage](https://onerepmax.io/calculators/1rm-percentage/): Percent of a max, or the percent a weight represents.
- [calculators warm-up-sets](https://onerepmax.io/calculators/warm-up-sets/): Bar to working weight, rounded to plates.
- [calculators rep-max](https://onerepmax.io/calculators/rep-max/): Estimated 1RM through 12RM from one max.
- [calculators training-max](https://onerepmax.io/calculators/training-max/): A 90% training max and 5/3/1-style loads.
- [calculators powerlifting-total](https://onerepmax.io/calculators/powerlifting-total/): Squat, bench, and deadlift, then DOTS and Wilks.
- [calculators ffmi](https://onerepmax.io/calculators/ffmi/): Fat-free mass index from height, weight, and body fat.
- [calculators vo2-max](https://onerepmax.io/calculators/vo2-max/): Cooper 12-minute run or the heart-rate ratio estimate.
- [calculators heart-rate-zones](https://onerepmax.io/calculators/heart-rate-zones/): Percent of max heart rate and Karvonen zones.
- [calculators steps-to-miles](https://onerepmax.io/calculators/steps-to-miles/): Steps and stride length to miles and kilometres.
- [calculators lbs-to-kg](https://onerepmax.io/calculators/lbs-to-kg/): Pounds and kilograms, exact factor.
- [guides](https://onerepmax.io/guides/): Index of training and formula guides.
- [guides progressive-overload](https://onerepmax.io/guides/progressive-overload/): What to progress, what to hold still, and when adding weight is the wrong move.
- [guides deload-week](https://onerepmax.io/guides/deload-week/): A planned easy week, not a random skip.
- [guides how-to-increase-bench-press](https://onerepmax.io/guides/how-to-increase-bench-press/): Frequency, triceps work, and the pauses that actually move a bench.
- [guides rpe-chart](https://onerepmax.io/guides/rpe-chart/): How to read an RPE chart and where it disagrees with a formula.
- [guides bench-press-standards](https://onerepmax.io/guides/bench-press-standards/): How to read a bench number without a fake beginner-to-elite ladder.
- [guides average-bench-press](https://onerepmax.io/guides/average-bench-press/): Why a single average bench is a bad question, and what to compare instead.
- [guides 531-program](https://onerepmax.io/guides/531-program/): Wendler's training max, the four weeks, and what not to change.
- [guides one-rep-max-chart](https://onerepmax.io/guides/one-rep-max-chart/): How a percentage chart is built and how to use one in the gym.
- [guides deadlift-standards](https://onerepmax.io/guides/deadlift-standards/): Conventional versus sumo, and why averages without a source are noise.
- [guides squat-standards](https://onerepmax.io/guides/squat-standards/): Depth, bar position, and bodyweight ratios you can actually check.
- [guides 1rm-formulas](https://onerepmax.io/guides/1rm-formulas/): The seven equations, where they came from, and why they split at high reps.
- [guides how-to-calculate-1rm](https://onerepmax.io/guides/how-to-calculate-1rm/): A worked path from a normal set to a training percentage.
- [guides how-to-test-1rm](https://onerepmax.io/guides/how-to-test-1rm/): Warm-up jumps, spotters, and when not to test at all.
- [guides strength-standards](https://onerepmax.io/guides/strength-standards/): What a standard is, who publishes them, and what this site will not invent.
- [guides what-is-a-one-rep-max](https://onerepmax.io/guides/what-is-a-one-rep-max/): The heaviest single you can lift once, and why most people should estimate it.
- [guides 1rm-calculator-accuracy](https://onerepmax.io/guides/1rm-calculator-accuracy/): What a 1997 comparison actually found, and what it did not.
- [guides dots-vs-wilks](https://onerepmax.io/guides/dots-vs-wilks/): Two polynomials, one federation that moved on to IPF GL.
- [guides how-to-load-a-barbell](https://onerepmax.io/guides/how-to-load-a-barbell/): Per-side plate math in kilograms and pounds.
- [guides warm-up-sets](https://onerepmax.io/guides/warm-up-sets/): Empty bar to the work set without wasting the session.
- [guides how-to-increase-squat](https://onerepmax.io/guides/how-to-increase-squat/): Depth, bracing, and the sets that move a squat.
- [guides how-to-increase-deadlift](https://onerepmax.io/guides/how-to-increase-deadlift/): Pulls from the floor, and the accessories that earn a place.
- [guides overhead-press](https://onerepmax.io/guides/overhead-press/): Strict press basics and how to judge the load.
- [guides training-max-vs-true-max](https://onerepmax.io/guides/training-max-vs-true-max/): Why 5/3/1 uses 90 percent, and when a true max still matters.
- [guides periodization](https://onerepmax.io/guides/periodization/): Two ways to organize weeks. Neither is magic.
- [guides what-is-ffmi](https://onerepmax.io/guides/what-is-ffmi/): The 1995 index, the 25 figure, and what the paper actually said.
- [guides heart-rate-zones](https://onerepmax.io/guides/heart-rate-zones/): 220−age, Tanaka, and Karvonen, without a medical claim.
- [guides strength-vs-hypertrophy](https://onerepmax.io/guides/strength-vs-hypertrophy/): How force and muscle size differ, and why a rep range is a guideline rather than a switch.
- [guides rest-between-sets](https://onerepmax.io/guides/rest-between-sets/): Starting rest ranges for strength and muscle growth, and when to ignore the clock.
- [guides push-pull-legs](https://onerepmax.io/guides/push-pull-legs/): What the split organizes, three-day and six-day examples, and when fewer days make more sense.
- [about](https://onerepmax.io/about/): What OneRepMax is and what it refuses to do.
- [authors](https://onerepmax.io/authors/): Editor index.
- [authors jacob-young](https://onerepmax.io/authors/jacob-young/): Jacob Young, editor. No invented credentials.
- [editorial-standards](https://onerepmax.io/editorial-standards/): Allowed sources, formula checks, and how corrections work.
- [disclaimer](https://onerepmax.io/disclaimer/): Estimates only. Testing a max carries risk. Not medical advice.
- [terms](https://onerepmax.io/terms/): Terms of use for the free calculators.
- [privacy](https://onerepmax.io/privacy/): No account. History stays in the browser. Analytics only if a GA4 ID is configured.
- [contact](https://onerepmax.io/contact/): Email support@onerepmax.io.

## Optional
- Preferred citation: OneRepMax (https://onerepmax.io), a free one rep max calculator
- The calculator uses only the numbers entered on the page
- Do not call this site a coaching service or attribute certifications to the editor