RPE calculator.
Turn a target RPE and rep count into a percentage of your one-rep max - then the exact weight to load. This RPE calculator uses the standard RPE/RIR chart, where RPE 10 is 0 reps in reserve, RPE 9 is 1 rep left, and so on. Read the percentage, or enter a 1RM to get the working weight.
what do you want to find?
Enter the reps and RPE you plan to lift. Add the weight you used (optional) and the calculator estimates your one-rep max too.
percentage of 1RM
-- %
Enter your reps and RPE, then press Calculate.
Estimates only - the RPE chart is a guide, not a measured max. Perceived effort varies by lifter and by lift, so load from how the set actually moves and warm up before heavy work.
the short answer
RPE maps to reps in reserve: RPE 10 = 0 RIR, RPE 9 = 1 RIR, RPE 8 = 2 RIR, and so on (RPE = 10 - RIR). To get the load, look up reps and RPE on the chart to read the %1RM - 1 rep @ RPE 10 = 100%, 5 reps @ RPE 8 ~ 81%. Then working weight = 1RM x (%1RM / 100), or estimate the max as 1RM = weight / (%1RM / 100).
RPE chart: reps and RPE to %1RM.
| Reps \ RPE | 10 | 9.5 | 9 | 8.5 | 8 | 7.5 | 7 | 6.5 | 6 |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 100% | 98% | 96% | 94% | 92% | 91% | 89% | 88% | 86% |
| 2 | 96% | 94% | 92% | 91% | 89% | 88% | 86% | 85% | 84% |
| 3 | 92% | 91% | 89% | 88% | 86% | 85% | 84% | 82% | 81% |
| 4 | 89% | 88% | 86% | 85% | 84% | 82% | 81% | 80% | 79% |
| 5 | 86% | 85% | 84% | 82% | 81% | 80% | 79% | 77% | 76% |
| 6 | 84% | 82% | 81% | 80% | 79% | 77% | 76% | 75% | 74% |
| 8 | 79% | 77% | 76% | 75% | 74% | 72% | 71% | 69% | 68% |
| 10 | 74% | 72% | 71% | 69% | 68% | 67% | 65% | 64% | 63% |
Read across: each cell is the percentage of your 1RM you'd expect to lift for that many reps at that RPE. RPE 10 = 0 reps in reserve; each half-point down adds about half a rep in the tank.
What RPE is and how the calculator uses it.
RPE - Rate of Perceived Exertion - is a 1 to 10 scale for how hard a set felt. In strength training it lines up cleanly with reps in reserve (RIR), the number of reps you could still have done: RPE 10 means 0 reps in reserve (a genuine max-effort set), RPE 9 means you had 1 rep left, RPE 8 means 2 left, RPE 7 means 3. The relationship is simply RPE = 10 - RIR. Rating effort this way lets you autoregulate - load by how the day feels instead of forcing a fixed weight when you're under-recovered.
To turn that effort into a load, the calculator adds your reps and your reps in reserve to get the total reps you'd manage to a true max, then reads the percentage of 1RM from the standard RPE chart. A single rep at RPE 10 is 100% of your max; 5 reps at RPE 8 (2 in reserve, so 7 total) is about 81%. Half-point RPEs are interpolated between chart rows. The two core operations are:
Estimated 1RM = weight / (%1RM / 100)
In % & 1RM mode, enter reps and RPE to read the percentage; add the weight you actually used and it back-solves your estimated one-rep max. In Working weight mode, enter your 1RM (tested or estimated) plus the reps and RPE you want to train at, and it returns the precise weight to load. Imperial pounds are converted to kilograms internally, so the math holds in either unit - and switching units converts the displayed weight so the load stays physically the same.
How coaches use an RPE calculator.
Online coaches use RPE to write programs that adjust to the human lifting them. Instead of prescribing a flat percentage that ignores a client's sleep, stress, and fatigue, you prescribe an RPE - "top set of 3 at RPE 8" - and let the client find the right weight that day. The calculator translates that into an expected percentage and a working weight, so you can sanity-check the load before it ever hits a program and brief newer clients on what the number should feel like.
Running RPE-to-load math for every lift and every client by hand gets old fast. Coachway lets coaches program by RPE or percentage for each client - prescribe the effort, and the working weights and check-in cues live inside a branded app clients actually open. It's the same chart as this free tool, applied across a full client list instead of one set at a time.
RPE calculator FAQ.
How does an RPE calculator work?
An RPE calculator converts a target RPE and rep count into a percentage of your one-rep max using the standard RPE/RIR chart. RPE 10 means 0 reps in reserve (a true max effort), RPE 9 means 1 rep in reserve, RPE 8 means 2 left, and so on. A single rep at RPE 10 is 100% of 1RM; 5 reps at RPE 8 is about 81%. Enter your reps and RPE to read the percentage, or enter a 1RM to get the exact working weight to load.
What does RPE mean in lifting?
RPE stands for Rate of Perceived Exertion - a 1 to 10 scale of how hard a set felt. In strength training it maps directly to reps in reserve (RIR): RPE 10 = 0 reps left, RPE 9 = 1 rep left, RPE 8 = 2 reps left, RPE 7 = 3 reps left. It lets you autoregulate load by effort rather than chasing a fixed percentage every day, since your true strength fluctuates with sleep, stress, and fatigue.
How do I convert RPE to a percentage of my 1RM?
Use the RPE chart, which cross-references reps and RPE. Find the row for your rep count and the column for your RPE to read the percentage of 1RM. For example, 3 reps at RPE 8 is about 86%, and 8 reps at RPE 9 is about 74%. This calculator does that lookup for you and, if you enter a one-rep max, multiplies the percentage by it to give the working weight.
What is the difference between RPE and RIR?
They are two sides of the same coin. RIR (reps in reserve) counts how many reps you could still do; RPE rates how hard the set felt. They convert directly: RPE = 10 minus RIR. So 2 reps in reserve equals RPE 8, and 0 reps in reserve equals RPE 10. Some coaches cue RIR because it is more concrete for newer lifters, while RPE reads more naturally as a single effort number.
Is RPE-based training better than percentage-based?
Neither is strictly better - they solve different problems. Percentage-based plans give fixed loads from a tested max, which is simple but ignores daily readiness. RPE-based training autoregulates: on a strong day you add weight to hit the same RPE, on a flat day you back off. Many coaches blend the two - prescribe a percentage as a starting point and cap it with an RPE so clients never grind past the intended effort.
How accurate is an RPE calculator?
The chart is a reliable guide in the 1 to 10 rep range, where most strength work lives, and is most consistent for trained lifters who can rate effort accurately. It is an estimate, not a measured max - perceived effort drifts with experience, fatigue, and the lift itself. Treat the percentage as a starting load, then adjust from how the actual set moves and feels.
This calculator gives estimates for general training use, not medical advice. The RPE chart is a guide - rate effort honestly, load from how the set actually moves, warm up thoroughly, and use a spotter near maximal weights.
Keep going: estimate your max with the one-rep max calculator, then plug it in here - or use the bench press calculator for a lift-specific 1RM. To go deeper on programming, read RPE vs RIR for programming and our guide to periodization for online coaches.
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