This one rep max calculator estimates your max from a set of 1 to 10 reps, then plans double progression for the dumbbells you own.
Estimates get unreliable above 10 reps. Repeat the set with a heavier weight so you stop at 10 reps or fewer.
The two numbers are the spread between formulas, not an error bar.
| Reps | Load | % of 1RM |
|---|
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Jump check
- Jump
When the weight can’t go up Coaching guidance
- Extend the rep ceiling. Keep the weight and work up to — reps per set before anything else.
- Slow the lowering. Same reps, but take about 3 seconds to lower the weight on every rep.
- Pause in the stretch. Hold 1–2 seconds at the stretched position (bottom of the squat, arms long on a row).
- Add one set. Add a set before you push reps past the extended ceiling.
- Move to a harder variation. Squat → split squat → rear-foot-elevated split squat. Hinge → B-stance → single-leg Romanian deadlift. Push-up → feet-elevated push-up. Row → single-arm row with a pause at the top.
- Re-estimate. Once a new best set is in, run it through the estimator again.
Adding reps at the same weight is a legitimate way to progress: in an 8-week study of trained lifters, progressing repetitions and progressing load produced similar muscle and strength results [7].
| Session | Weight | Target reps |
|---|
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Your one rep max (1RM) is the heaviest weight you could lift for a single clean rep. You don’t have to test it: lift a weight for 1 to 10 hard reps, enter the numbers, and the calculator estimates your max with the Epley equation [1], with the Brzycki equation as a cross-check [2]. The second tab turns that number into a plan. It applies double progression to the dumbbells you actually own: add reps until you hit the top of your range on every set, then add weight. If you have no heavier pair, it tells you what to do instead.
How to use this calculator
On Estimate my max, pick your lift, enter the weight and the reps you completed, and optionally how many more reps you had left (reps in reserve). For dumbbells, enter one dumbbell: every result is per hand. The result updates as you type: your estimated max, a rep-to-load table from 1 to 10 reps, and a short reading of the number.
On Plan my progression, choose a rep range, your sets, the weight you are using now and the dumbbells you own, either a list of fixed pairs or the smallest jump on an adjustable set. Enter last session’s reps for each set. You get the weight and target reps for next session, a check on whether the next weight jump is too big, and the next four sessions.
1RM percentage chart (printable)
Use the chart to set training loads without running the calculator each time. The left block converts reps into a percentage of your max. The right block turns any 1RM into loads from 50% to 100%. After you calculate, your nearest row is highlighted and your exact numbers appear at the top. Printing needs no email.
| Reps | % of 1RM |
|---|---|
| 1 | 100.0% |
| 2 | 93.8% |
| 3 | 90.9% |
| 4 | 88.2% |
| 5 | 85.7% |
| 6 | 83.3% |
| 7 | 81.1% |
| 8 | 78.9% |
| 9 | 76.9% |
| 10 | 75.0% |
The chart stops at 10 reps: past that, rep-based estimates get unreliable. How we calculate it
| 1RM | 50% | 55% | 60% | 65% | 70% | 75% | 80% | 85% | 90% | 95% | 100% |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Your estimate | |||||||||||
| 20 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| 30 | 15 | 16.5 | 18 | 19.5 | 21 | 22.5 | 24 | 25.5 | 27 | 28.5 | 30 |
| 40 | 20 | 22 | 24 | 26 | 28 | 30 | 32 | 34 | 36 | 38 | 40 |
| 50 | 25 | 27.5 | 30 | 32.5 | 35 | 37.5 | 40 | 42.5 | 45 | 47.5 | 50 |
| 60 | 30 | 33 | 36 | 39 | 42 | 45 | 48 | 51 | 54 | 57 | 60 |
| 70 | 35 | 38.5 | 42 | 45.5 | 49 | 52.5 | 56 | 59.5 | 63 | 66.5 | 70 |
| 80 | 40 | 44 | 48 | 52 | 56 | 60 | 64 | 68 | 72 | 76 | 80 |
| 90 | 45 | 49.5 | 54 | 58.5 | 63 | 67.5 | 72 | 76.5 | 81 | 85.5 | 90 |
| 100 | 50 | 55 | 60 | 65 | 70 | 75 | 80 | 85 | 90 | 95 | 100 |
| 110 | 55 | 60.5 | 66 | 71.5 | 77 | 82.5 | 88 | 93.5 | 99 | 104.5 | 110 |
| 120 | 60 | 66 | 72 | 78 | 84 | 90 | 96 | 102 | 108 | 114 | 120 |
| 130 | 65 | 71.5 | 78 | 84.5 | 91 | 97.5 | 104 | 110.5 | 117 | 123.5 | 130 |
| 140 | 70 | 77 | 84 | 91 | 98 | 105 | 112 | 119 | 126 | 133 | 140 |
| 150 | 75 | 82.5 | 90 | 97.5 | 105 | 112.5 | 120 | 127.5 | 135 | 142.5 | 150 |
| 160 | 80 | 88 | 96 | 104 | 112 | 120 | 128 | 136 | 144 | 152 | 160 |
| 170 | 85 | 93.5 | 102 | 110.5 | 119 | 127.5 | 136 | 144.5 | 153 | 161.5 | 170 |
| 180 | 90 | 99 | 108 | 117 | 126 | 135 | 144 | 153 | 162 | 171 | 180 |
| 190 | 95 | 104.5 | 114 | 123.5 | 133 | 142.5 | 152 | 161.5 | 171 | 180.5 | 190 |
| 200 | 100 | 110 | 120 | 130 | 140 | 150 | 160 | 170 | 180 | 190 | 200 |
Plain percentages of a 1RM, rounded to the nearest 0.5 kg.
| 1RM | 50% | 55% | 60% | 65% | 70% | 75% | 80% | 85% | 90% | 95% | 100% |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Your estimate | |||||||||||
| 50 | 25 | 28 | 30 | 33 | 35 | 38 | 40 | 43 | 45 | 48 | 50 |
| 75 | 38 | 41 | 45 | 49 | 53 | 56 | 60 | 64 | 68 | 71 | 75 |
| 100 | 50 | 55 | 60 | 65 | 70 | 75 | 80 | 85 | 90 | 95 | 100 |
| 125 | 63 | 69 | 75 | 81 | 88 | 94 | 100 | 106 | 113 | 119 | 125 |
| 150 | 75 | 83 | 90 | 98 | 105 | 113 | 120 | 128 | 135 | 143 | 150 |
| 175 | 88 | 96 | 105 | 114 | 123 | 131 | 140 | 149 | 158 | 166 | 175 |
| 200 | 100 | 110 | 120 | 130 | 140 | 150 | 160 | 170 | 180 | 190 | 200 |
| 225 | 113 | 124 | 135 | 146 | 158 | 169 | 180 | 191 | 203 | 214 | 225 |
| 250 | 125 | 138 | 150 | 163 | 175 | 188 | 200 | 213 | 225 | 238 | 250 |
| 275 | 138 | 151 | 165 | 179 | 193 | 206 | 220 | 234 | 248 | 261 | 275 |
| 300 | 150 | 165 | 180 | 195 | 210 | 225 | 240 | 255 | 270 | 285 | 300 |
| 325 | 163 | 179 | 195 | 211 | 228 | 244 | 260 | 276 | 293 | 309 | 325 |
| 350 | 175 | 193 | 210 | 228 | 245 | 263 | 280 | 298 | 315 | 333 | 350 |
| 375 | 188 | 206 | 225 | 244 | 263 | 281 | 300 | 319 | 338 | 356 | 375 |
| 400 | 200 | 220 | 240 | 260 | 280 | 300 | 320 | 340 | 360 | 380 | 400 |
| 425 | 213 | 234 | 255 | 276 | 298 | 319 | 340 | 361 | 383 | 404 | 425 |
| 450 | 225 | 248 | 270 | 293 | 315 | 338 | 360 | 383 | 405 | 428 | 450 |
Plain percentages of a 1RM, rounded to the nearest 1 lb.
One formula for bench, squat and deadlift
The lift selector covers the bench press, squat, deadlift, overhead press, dumbbell work and weighted pull-ups or dips on this one page. It changes the labels, not the maths: every lift uses the same Epley equation and the same 10-rep cap. That is a simplification. A meta-regression of 269 studies found more reps in the leg press than in the bench press at the same percentage of 1RM, so the authors built separate tables for those two lifts and found one general table fits other exercises [5]. A tested 1RM is reliable for upper- and lower-body, single- and multi-joint exercises alike [3]. Dumbbell values are per hand.
How to read your result
An estimate, not a test result
The headline number comes from the Epley equation, 1RM = weight × (1 + reps ÷ 30). The Brzycki result is shown next to it. The two formulas differ by a few percent across 2–6 reps and meet at 10 reps, so the pair shows how much the formulas disagree. It is not an error bar for you personally.
Rep-based estimates work. Reynolds et al. tested 70 men and women on the bench press and leg press and found that 1RM can be estimated accurately from multiple-rep sets, with 5-rep sets giving the best prediction [4]. Your own error depends on you. The number of reps people manage at a given percentage of their max varies between individuals, and it varies by exercise: a large meta-regression found more reps in the leg press than in the bench press at the same relative load [5]. Even a real max test moves from day to day. Across 32 studies, the median coefficient of variation for repeated 1RM tests was 4.2% [3].
Use the estimate to choose training weights, and re-estimate when your sets improve.
Why the calculator stops at 10 reps
Long sets predict a max poorly. Reynolds et al. concluded that no more than 10 repetitions should be used in linear equations to estimate 1RM [4], so 10 is a hard limit here. Reps in reserve count toward it: 8 reps with 3 left in the tank describes an 11-rep effort, and the calculator will ask you to retest with a heavier weight.
Reps in reserve are a practical way to rate how hard a set was: 0 means you could not have done another clean rep, 2 means two more were there. The scale was validated as a training tool by Zourdos et al. [8]. You don’t need to reach failure for the estimate to be useful. In a meta-analysis, training to momentary failure was not better for muscle growth than stopping short of it [11].
Dumbbell values are per hand
With dumbbells, enter one dumbbell, and the estimate is your max for one dumbbell in each hand. Don’t double it and compare it with a barbell number. The research behind these equations mostly tested barbell and machine lifts such as the bench press and leg press [4] [5], and balancing two independent weights is a different task. Treat dumbbell numbers as your own benchmark, and compare them only with your own later dumbbell sets.
Using the rep-to-load table
The table runs the Epley equation backwards: for each rep count from 1 to 10, it gives the load that matches your estimated max, and its percentage of 1RM (93.8% at 2 reps, 85.7% at 5, 75% at 10). Use it to pick a starting weight for a new rep target, then adjust after the first set. If the target reps come easily, go up; if form breaks down, go down.
You don’t need heavy loads to build muscle. Meta-analyses comparing low- and high-load training found similar muscle growth across a wide range of loads, while gains in 1RM strength favoured heavier loads [6] [10]. For home training with limited dumbbells, that is the reason double progression works.
How double progression works
Double progression moves two variables in turn. Pick a rep range, for example 8–12. Keep the same weight and add reps, session by session, until every set reaches 12. Then move up one weight step and drop back to around 8 reps. The ACSM position stand on progression describes the same rule: increase the load by 2–10% once you can do one or two reps more than your target with the current weight [9].
With dumbbells, the second step is often the hard part. A jump from 14 kg to 16 kg is a 14% increase, bigger than the ACSM range. The planner checks every jump. It predicts your reps at the new weight from your last session, using the Epley equation when your average set was 10 reps or fewer and a cruder linear rule above that, labelled approximate. The rule of thumb behind it, about 2 fewer reps for every 5% more load in the 5–10 rep zone, is derived from the Epley equation itself, not from a separate study. If the prediction lands well below your range, the planner suggests a bridge first.
When the weight can’t go up at all, the planner switches to a ladder: extend the rep ceiling, slow the lowering phase, pause in the stretch, add a set, then move to a harder variation. These steps are coaching guidance. The evidence behind the reps-first approach is that progressing repetitions and progressing load produced similar results over 8 weeks in trained lifters [7]. For a full routine to apply this to, see the dumbbell shoulder workout at home.
Fuel your progression
Getting stronger at home is limited by recovery as well as by your dumbbells. Protein matters most for recovery: getting enough of it every day supports the muscle you are building between sessions. The protein intake calculator gives you a daily target in grams for your bodyweight and goal, and splits it across your meals. If your reps stall for several sessions while your sleep and protein are low, fix those before you change the plan.
Save your results
Get your max, your rep table and your next-session targets by email.
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✓ Check your inbox — your results are on their way.
Frequently asked questions
How do I calculate my one rep max without lifting a maximum?
Take a weight you can lift for 1 to 10 clean reps, do one hard set, and enter the weight and reps into the calculator. It applies the Epley equation, 1RM = weight × (1 + reps ÷ 30), and shows the Brzycki result alongside it. Reynolds et al. (2006) found that 1RM can be estimated accurately from multiple-repetition testing, with sets of about 5 reps giving the best prediction. You never need to attempt a true maximal lift to use the number for programming.
How accurate is a 1RM estimate from the Epley formula?
It is a good starting point, not an exact measurement. Accuracy is best with fewer reps: Reynolds et al. (2006) found 5-rep sets predicted 1RM better than 10- or 20-rep sets. How many reps a person can do at a given percentage of their max also varies between individuals and between exercises; Nuzzo et al. (2024) found more reps at the same percentage in the leg press than in the bench press. Even a real 1RM test moves from day to day: across 32 studies, Grgic et al. (2020) report a median coefficient of variation of 4.2%.
Why does the calculator stop at 10 reps?
Because predictions get less reliable as the set gets longer. Reynolds et al. (2006) concluded that no more than 10 repetitions should be used in linear equations to estimate 1RM. Reps in reserve count toward the limit too: 8 reps with 3 more in the tank is an 11-rep effort, so the calculator asks you to repeat the set with a heavier weight and stop at 10 reps or fewer.
What is double progression and how does it work?
Double progression is a way to progress two variables in turn: reps first, then load. You pick a rep range, such as 8–12, and keep the same weight until you reach the top of the range on every set. Then you move up one weight step and start again near the bottom of the range. The ACSM position stand on progression (2009) describes the same logic: increase the load by 2–10% once you can perform the current workload for one or two repetitions over the desired number.
What if my dumbbells are too light to keep progressing?
Keep progressing without adding weight. The planner switches to a ladder: extend your rep ceiling, slow the lowering phase, pause in the stretched position, add a set, then move to a harder variation such as a rear-foot-elevated split squat. Plotkin et al. (2022) compared adding load with adding repetitions over 8 weeks in trained lifters and found both were viable ways to improve muscle size and strength. The ladder steps themselves are coaching guidance, not tested protocols.
Can I use this for dumbbells, and why is there no resistance-band option?
Yes. Choose dumbbells and enter the weight of one dumbbell: the result is your estimated max per hand, and it does not convert to a barbell number. There is no band option on purpose. A band's resistance changes as it stretches, so a single weight and rep count cannot describe the load you lifted, and any 1RM figure would look precise without being meaningful.
Do I need to test my real max, and is it safe?
No. A hard submaximal set of 1–10 reps is enough for programming, and you do not need to train to failure to use this tool: Refalo et al. (2023) found no evidence that training to momentary failure is better for muscle growth than stopping short of it. The calculator is designed for healthy adults. Stop any set that causes pain, and ask a qualified professional for advice on injuries or medical conditions. Our methodology page explains every formula used.
Sources
- Epley B (1985). Poundage Chart. Boyd Epley Workout, University of Nebraska.
- Brzycki M (1993). Strength testing: predicting a one-rep max from reps-to-fatigue. Journal of Physical Education, Recreation & Dance. DOI
- Grgic J, Lazinica B, Schoenfeld BJ, Pedisic Z (2020). Test-retest reliability of the one-repetition maximum (1RM) strength assessment: a systematic review. Sports Medicine - Open. PMID 32681399 DOI
- Reynolds JM, Gordon TJ, Robergs RA (2006). Prediction of one repetition maximum strength from multiple repetition maximum testing and anthropometry. Journal of Strength and Conditioning Research. PMID 16937972 DOI
- Nuzzo JL, Pinto MD, Nosaka K, Steele J (2024). Maximal number of repetitions at percentages of the one repetition maximum: a meta-regression and moderator analysis of sex, age, training status, and exercise. Sports Medicine. PMID 37792272 DOI
- Schoenfeld BJ, Grgic J, Ogborn D, Krieger JW (2017). Strength and hypertrophy adaptations between low- vs. high-load resistance training: a systematic review and meta-analysis. Journal of Strength and Conditioning Research. PMID 28834797 DOI
- Plotkin D, Coleman M, Van Every D, et al. (2022). Progressive overload without progressing load? The effects of load or repetition progression on muscular adaptations. PeerJ. PMID 36199287 DOI
- Zourdos MC, Klemp A, Dolan C, et al. (2016). Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. Journal of Strength and Conditioning Research. PMID 26049792 DOI
- American College of Sports Medicine (2009). American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Medicine & Science in Sports & Exercise. PMID 19204579 DOI
- Lopez P, Radaelli R, Taaffe DR, et al. (2021). Resistance training load effects on muscle hypertrophy and strength gain: systematic review and network meta-analysis. Medicine & Science in Sports & Exercise. PMID 33433148 DOI
- Refalo MC, Helms ER, Trexler ET, Hamilton DL, Fyfe JJ (2023). Influence of resistance training proximity-to-failure on skeletal muscle hypertrophy: a systematic review with meta-analysis. Sports Medicine. PMID 36334240 DOI
Methodology: every equation and rule used here, including the 10-rep cap and the jump check, is documented on our methodology page. Last reviewed: October 2026.
Safety note: this calculator is for healthy adults. It never asks you to test a true maximum or train to failure. Stop any set that causes pain, and ask a qualified professional for advice about injuries, medical conditions or a training plan built for you.