Strength Training Calculator
Calculate training weights from your 1RM across all rep ranges and RPE levels.
Your Lift
Estimated 1-Rep Max
116.7
±5% accuracy · Epley formula
Rep-Max Table
| Reps | % of 1RM | Est. Weight |
|---|---|---|
| 1 | 100% | 116.7 |
| 2 | 95% | 110.8 |
| 3 | 93% | 108.5 |
| 4 | 90% | 105.0 |
| 5 | 87% | 101.5 |
| 6 | 85% | 99.2 |
| 7 | 83% | 96.8 |
| 8 | 80% | 93.3 |
| 9 | 77% | 89.8 |
| 10 | 75% | 87.5 |
| 12 | 70% | 81.7 |
| 15 | 65% | 75.8 |
| 20 | 60% | 70.0 |
RPE Reference Table
RPE (Rate of Perceived Exertion) — how many reps in reserve you have left.
| RPE | % of 1RM | Est. Weight |
|---|---|---|
| 10 | 100% | 116.7 |
| 9.5 | 98% | 114.3 |
| 9 | 96% | 112.0 |
| 8.5 | 94% | 109.7 |
| 8 | 92% | 107.3 |
| 7.5 | 90% | 105.0 |
| 7 | 88% | 102.7 |
| 6 | 83% | 96.8 |
About Strength Training Calculator
This calculator estimates your one-rep maximum (1RM) — the heaviest weight you can lift for a single repetition — based on a weight you lifted for multiple reps. Enter the weight you used and how many reps you completed, then choose a formula. The Epley and Brzycki formulas are the most widely used; Lombardi and MacDougall offer alternative models. Once your 1RM is estimated, the rep-max table shows training weights for every rep range from 1 to 20, and the RPE reference table maps Rate of Perceived Exertion levels to target intensities. Note that all 1RM estimates carry approximately ±5% accuracy — individual neuromuscular efficiency, fatigue, and exercise selection all affect real-world results.
Built and maintained by Meet Shah · Last updated
What this tool is used for
- Working out working weights for a rep range from a one-rep max.
- Comparing percentage-based and RPE-based prescriptions.
- Producing a set of loads for a training block.
- Checking a programme's percentages against your current max.
- Adjusting loads after a max has changed.
Frequently Asked Questions
- What is progressive overload?
- Gradually increasing the demand — load, reps, sets or density — so adaptation continues. It is the one principle every programme shares, and stalling almost always means the progression outran recovery rather than that the exercise stopped working.
- How do rep ranges differ in effect?
- 1–5 reps at high load favours neural adaptation and maximal strength; 6–12 is the classic hypertrophy range; 15+ builds endurance. The ranges overlap far more than the traditional model suggests — hypertrophy is achievable across a wide band if the sets are near failure.
- What is RPE and why use it?
- Rate of perceived exertion, usually as reps in reserve — RPE 8 means two more were possible. It adjusts the day's load to how you actually feel, which fixed percentages cannot do, and it is why autoregulated programmes tolerate bad weeks better.
- What does volume actually mean?
- Sets × reps × load, though weekly hard sets per muscle group is the more useful figure — roughly 10 to 20 for most trainees. Beyond that the returns flatten and recovery becomes the limit rather than the stimulus.
- How much rest between sets?
- Three to five minutes for heavy compound work, where the goal is a full effort each set, and one to two for accessory work. Cutting rest short reduces the load you can move, which quietly turns a strength session into an endurance one.
Common errors and gotchas
- Using a stale one-rep max, which makes every derived load wrong in the same direction.
- Applying one lift's percentages to another, where the rep-to-percentage relationship differs.
- Treating a percentage table as exact, when daily readiness moves it several per cent.
- Deriving loads from an estimated rather than a tested max, which compounds two approximations.
- Rounding to a plate increment without noticing the jump is a large share of the load.