Strength calculator
One-Rep Max Calculator with 1RM Percentages
Estimate your one-repetition maximum (1RM) from a submaximal set, then see common percentages of 1RM for planning session loads.
Estimated one-rep max
216 lb
Brzycki estimate: 208 lb
185 × (1 + 5 ÷ 30) = 216How nearby inputs change it
Percent of 1RM
Use these percentages of the Epley estimated 1RM to plan session loads. This is a reference table, not a training program.
| Percentage of estimated 1RM | Working weight |
|---|---|
| 50% | 108 lb |
| 60% | 130 lb |
| 70% | 151 lb |
| 75% | 162 lb |
| 80% | 173 lb |
| 85% | 183 lb |
| 90% | 194 lb |
| 95% | 205 lb |
Loads are rounded to the nearest whole lb or kg for display. They are not rounded to available plates.
This is an estimate for general fitness planning, not medical advice.
Estimate.
174.0 lb
p = 87.0%
200 × 87.0 ÷ 100 = 174.0Percentage from Helms ER, Cronin J, Storey A, Zourdos MC. Strength Cond J. 2016;38(4):42-49. Table 2. PMC4961270. The reps-in-reserve scale is described in Zourdos MC, Klemp A, Dolan C, et al. J Strength Cond Res. 2016;30(1):267-275. doi:10.1519/JSC.0000000000001049.
The chart comes from trained lifters doing the barbell back squat. Only three cells were measured directly; the rest are the authors' estimates.
It may differ for machines, single-joint, or upper-body lifts, and individuals vary.
Newer lifters rate RPE less accurately; practice rating sets before using RPE to choose loads.
How the one-rep max estimate works
A one-repetition maximum (1RM) is the heaviest load you can lift once with the specified technique and range of motion. This calculator estimates it from weight and repetitions instead of requiring a maximal attempt. Its primary result uses Epley: weight × (1 + repetitions ÷ 30). It also reports Brzycki:weight × 36 ÷ (37 − repetitions). The Epley equation is attributed toEpley B., Boyd Epley Workout (1985), p. 86 (Source attributed to the Epley one-repetition maximum equation.); the comparison equation comes from Brzycki M., JOPERD 64 (1993), p. 88 (Secondary repetitions-to-1RM equation.).
A worked 1RM example
Imagine completing 185 lb for five good repetitions. Epley gives 185 × (1 + 5 ÷ 30) =215.8 lb. Brzycki gives 185 × 36 ÷ (37 − 5) = 208.1 lb. Reporting both values shows a roughly eight-pound model spread. For programming, a lifter might round the Epley estimate to an available load, then calculate 80% as about 173 lb and choose 170 or 175 lb depending on available plates. Those percentages describe a plan, not a requirement to complete a fixed number of repetitions on every day. Fatigue, exercise order, sleep, confidence, and rest intervals can all alter performance.
Bench press max calculator
To use this page as a bench press max calculator, choose Bench press in the Lift menu, enter the weight from a recent hard set and the reps you completed, and read the estimated one-rep max. The Lift menu only labels the result. This page applies the same Epley and Brzycki equations shown above to bench press, squat and deadlift, so the same weight and reps give the same numbers whichever lift is chosen.
A worked bench press example: 225 lb for 6 reps. Epley gives 225 × (1 + 6 ÷ 30) = 270.0 lb. Brzycki gives 225 × 36 ÷ (37 − 6) = 261.3 lb. The calculator displays these as 270 lb and 261 lb. In the percent table, 80% of the Epley estimate is 216 lb.
Enter reps done to the same standard each time. A paused bench press, a touch-and-go set and a different grip width produce sets that are not interchangeable, so compare a bench estimate only with earlier bench sets done the same way. The page does not compare a result with other lifters or rate it by bodyweight, age or sex.
Squat max calculator
Choose Squat in the Lift menu and enter a set the same way. A worked squat example in kilograms: 100 kg for 6 reps. Epley gives 100 × (1 + 6 ÷ 30) = 120.0 kg, and Brzycki gives 100 × 36 ÷ (37 − 6) =116.1 kg, displayed as 120 kg and 116 kg. Keep depth, bar position and stance the same between the sets you compare. The RPE chart mode on this page was published for the barbell back squat, so a back squat set rated by reps in reserve can also be entered there.
Deadlift max calculator
Choose Deadlift in the Lift menu. A worked deadlift example: 315 lb for 4 reps. Epley gives 315 × (1 + 4 ÷ 30) = 357.0 lb, and Brzycki gives 315 × 36 ÷ (37 − 4) =343.6 lb, displayed as 357 lb and 344 lb. Note whether each rep started from a dead stop on the floor or was touch-and-go, and compare conventional sets with conventional sets and sumo with sumo. Straps change the grip, so note whether a set used them.
Why repetition count and effort matter
The entered set needs to be representative. If 185 × 5 was stopped with five repetitions still available, formulas interpret it as a five-repetition maximum and underestimate capacity. Conversely, repetitions achieved with shortening range of motion, assistance, bouncing, or changed equipment are not equivalent to standardized repetitions. Use a hard set with consistent technique, but do not sacrifice safety merely to satisfy a calculator.
Estimates become especially uncertain above 10 repetitions. At higher counts, local muscular endurance, pacing, discomfort tolerance, and fiber-type differences contribute more, while both equations extrapolate farther from a maximal single. The calculator accepts higher values to let users inspect the math and displays a warning above 10 reps; that does not make a 20- or 30-rep prediction dependable. Prefer a clean set of about two to ten reps when estimating maximal strength.
Common mistakes
- Entering a warm-up set. A set far from failure does not reveal the repetition capacity assumed by these equations.
- Using high-repetition sets as precise tests. Above 10 reps, endurance and pacing increase uncertainty substantially.
- Changing the movement standard. Comparing touch-and-go with paused reps, partial with full depth, or different machines obscures actual progress.
- Loading the estimate automatically. An equation result is not proof that a maximal attempt is safe today; use sensible progression and competent spotting or safeties.
RPE calculator: one cell from the RPE chart, by reps in reserve
This page also works as an RPE calculator. Rate the set by reps in reserve, then read one percentage from the RPE chart published for the barbell back squat. The result quotes that single percentage and the citation. It does not list the rest of the chart.
There are two directions. To choose a load, enter a one-rep max, the reps you want, and a target RPE. The load is that one-rep max multiplied by the chart percentage. To estimate a one-rep max from a set you already lifted, enter the load, the reps, and the RPE. That estimate divides the load by the same percentage. Kilograms stay kilograms and pounds stay pounds. Only the final number is rounded, to one decimal place.
A 140 kg one-rep max for 5 reps at RPE 8 uses 81.0% of that max, which is 113.4 kg. The same cell in the other direction: 100 kg for 5 reps at RPE 8 is 81.0%, which estimates a123.5 kg one-rep max. RPE 10 means 0 reps left, RPE 9 means 1, RPE 8 means 2, and RPE 7 means 3. Half steps sit between those counts. When you have the load, theplate calculator turns it into plates per side.
Estimate. The chart comes from trained lifters doing the barbell back squat. Only three cells were measured directly; the rest are the authors' estimates. It may differ for machines, single-joint, or upper-body lifts, and individuals vary. Newer lifters rate RPE less accurately; practice rating sets before using RPE to choose loads.
Ratings below RPE 7, repetitions above 8, and values that are not on the half-step scale are outside the published chart, so the calculator returns no number. It also returns no number until the weight is greater than zero and the repetitions are a whole number.
- Helms ER, Cronin J, Storey A, Zourdos MC. Application of the repetitions in reserve-based rating of perceived exertion scale for resistance training. Strength Cond J. 2016;38(4):42-49.PMC4961270.
- Zourdos MC, Klemp A, Dolan C, et al. Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. J Strength Cond Res. 2016;30(1):267-275.doi:10.1519/JSC.0000000000001049.
Using percent of 1RM for session planning
The percentage table uses the Epley estimate as its reference. Round to equipment you can load, then account for the intended repetitions, total sets, and proximity to failure. A percentage appropriate for one lift may feel different on another because strength curves and technique differ. Beginners can improve skill quickly, while experienced lifters may express maximal strength more efficiently; one universal formula cannot model both perfectly. Track whether prescribed loads produce the intended effort and update the estimate from new, comparable sets.
To score a powerlifting total of your best squat, bench press, and deadlift against bodyweight, use the Wilks calculator.
Limitations and safety
This calculator cannot assess technique, readiness, pain, injury, supervision, equipment, or whether maximal lifting is appropriate. Results are estimates for general training planning, not medical advice or clearance to attempt the displayed load. Stop when pain, dizziness, or loss of control occurs, and seek qualified coaching or clinical advice when injury or health concerns affect lifting.
Sources
- Epley B., Boyd Epley Workout (1985), p. 86 — Source attributed to the Epley one-repetition maximum equation.
- Brzycki M., JOPERD 64 (1993), p. 88 — Secondary repetitions-to-1RM equation.
- Helms ER, Cronin J, Storey A, Zourdos MC. Strength Cond J. 2016;38(4):42-49.PMC4961270. Table 2 supplies the RPE chart percentages.
- Zourdos MC, Klemp A, Dolan C, et al. J Strength Cond Res. 2016;30(1):267-275.doi:10.1519/JSC.0000000000001049.
Frequently asked questions
Do I need to attempt a true one-rep max?
No. A challenging submaximal set can provide an estimate without requiring a maximal single. The estimate is still exercise-specific and depends on honest effort, stable technique, and an appropriate repetition range.
Why do Epley and Brzycki give different results?
They are different mathematical models fitted or proposed from different assumptions. Their disagreement is useful evidence of uncertainty, not an error that must be hidden.
Which set should I enter?
Use a recent, technically sound working set performed close to your normal full range of motion. A set of roughly two to ten repetitions is generally more informative than a high-repetition endurance set.
Can I compare 1RM estimates across exercises?
Use caution. Skill, equipment, range of motion, pauses, grip, and exercise mechanics differ. Compare an exercise with the same exercise performed under standardized conditions.
How often should I update training percentages?
Recalculate when a representative set improves or when technique, equipment, or training status changes. Round prescribed loads to available plates and adjust for daily readiness rather than treating every percentage as mandatory.
How is each percentage-of-1RM load calculated?
Each working weight is the selected percentage multiplied by the Epley 1RM estimate. Displayed loads are rounded to the nearest whole pound or kilogram, not automatically rounded to available plates.
What does RPE 8 mean in lifting?
On the scale used here, RPE 8 means 2 reps left, also called 2 reps in reserve. RPE 10 means 0 reps left, RPE 9 means 1, and RPE 7 means 3. A half step, such as 8.5, falls between the neighboring whole numbers. The rating describes that set, not a different exercise or a different day.
How do I use RPE to pick a weight?
Enter a one-rep max, the reps you want, and the RPE you want to hold. The calculator reads one percentage from the RPE chart and multiplies it by the one-rep max. The product is the estimated load, in the same unit you entered, rounded to one decimal place. Load the bar from that number with the plate calculator. To go the other way, enter the load you lifted, the reps, and the RPE to estimate a one-rep max.
How accurate is an RPE chart?
The chart comes from trained lifters doing the barbell back squat. Only three cells were measured directly; the rest are the authors' estimates. It may differ for machines, single-joint, or upper-body lifts, and individuals vary. Newer lifters rate RPE less accurately; practice rating sets before using RPE to choose loads. Entries outside the published reps and RPE values return no number.
How do I estimate my max bench from a set of reps?
Choose Bench press in the Lift menu, then enter the weight and the reps from a recent hard set. For 225 lb for 6 reps, Epley estimates 270 lb and Brzycki estimates 261 lb. The Lift menu labels the result; the equations are the same for every lift.
Can I use this as a squat or deadlift max calculator?
Yes. Choose Squat or Deadlift in the Lift menu. For example, 100 kg for 6 reps on the squat estimates 120 kg with Epley and 116 kg with Brzycki, and 315 lb for 4 reps on the deadlift estimates 357 lb and 344 lb. Compare each estimate only with earlier sets of the same lift done the same way.
Does choosing a lift change the calculation?
No. Bench press, squat and deadlift use the same Epley and Brzycki equations, so the same weight and reps give the same estimate whichever lift is chosen. Choosing a lift changes only the label on the result and in the copied result text.