Everything agrees
The chart, both calculators and the one rep max calculator use the same rule, so 3 reps at RPE 8 gives the same max as a 5-rep set to failure.
// FREE CALCULATOR //
RPE Calculator
RPE rates how hard a set was on a 10-point scale, read as reps in reserve: RPE 8 means about two reps left. Enter a set you did to estimate your max, then the set you want to get its load. The RPE chart under the calculator gives the percentage of your max for every reps and RPE pair.
RPE as reps in reserveChart from 1 to 12 repskg or lbNo sign-up
// ESTIMATED 1RM FROM YOUR SET //
277.5 lb
225 lb × 5 at RPE 8 is 2 in reserve, so it counts as 7 reps to failure: 81.1% of max (Epley).
// LOAD FOR 3 @ RPE 8 //
238 lb
85.7% of a 277.5 lb max, rounded to 0.5. Start there and adjust by feel.
| Reps | RPE 10 | RPE 9.5 | RPE 9 | RPE 8.5 | RPE 8 | RPE 7.5 | RPE 7 | RPE 6.5 | RPE 6 |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 100% | 95.2% | 93.8% | 92.3% | 90.9% | 89.6% | 88.2% | 87% | 85.7% |
| 2 | 93.8% | 92.3% | 90.9% | 89.6% | 88.2% | 87% | 85.7% | 84.5% | 83.3% |
| 3 | 90.9% | 89.6% | 88.2% | 87% | 85.7% | 84.5% | 83.3% | 82.2% | 81.1% |
| 4 | 88.2% | 87% | 85.7% | 84.5% | 83.3% | 82.2% | 81.1% | 80% | 78.9% |
| 5 | 85.7% | 84.5% | 83.3% | 82.2% | 81.1% | 80% | 78.9% | 77.9% | 76.9% |
| 6 | 83.3% | 82.2% | 81.1% | 80% | 78.9% | 77.9% | 76.9% | 75.9% | 75% |
| 7 | 81.1% | 80% | 78.9% | 77.9% | 76.9% | 75.9% | 75% | 74.1% | 73.2% |
| 8 | 78.9% | 77.9% | 76.9% | 75.9% | 75% | 74.1% | 73.2% | 72.3% | 71.4% |
| 9 | 76.9% | 75.9% | 75% | 74.1% | 73.2% | 72.3% | 71.4% | 70.6% | 69.8% |
| 10 | 75% | 74.1% | 73.2% | 72.3% | 71.4% | 70.6% | 69.8% | 69% | 68.2% |
| 11 | 73.2% | 72.3% | 71.4% | 70.6% | 69.8% | 69% | 68.2% | 67.4% | 66.7% |
| 12 | 71.4% | 70.6% | 69.8% | 69% | 68.2% | 67.4% | 66.7% | 65.9% | 65.2% |
// READING THE SCALE //
What each RPE feels like.
The reps-in-reserve scale from Zourdos and colleagues (2016): every point is one rep left in the tank.
| RPE | Reps in reserve | What it means |
|---|---|---|
| 10 | 0 | Maximal effort. No rep left. |
| 9.5 | 0 | No more reps, but a little more weight was possible. |
| 9 | 1 | One more rep was there. |
| 8.5 | 1 to 2 | One more for sure, maybe two. |
| 8 | 2 | Two more reps were there. |
| 7.5 | 2 to 3 | Two more for sure, maybe three. |
| 7 | 3 | Three more reps were there. |
| 5 to 6 | 4 to 6 | Four to six reps left. |
| 3 to 4 | — | Light effort. |
| 1 to 2 | — | Little to no effort. |
// HOW THE CHART IS BUILT //
One rule, shown in full.
// PERCENT OF 1RM, EPLEY //
% of 1RM = 1 ÷ (1 + (reps + reps in reserve) ÷ 30)
Worked example: 5 reps at RPE 8 is 2 in reserve, so 7 reps to failure, and 1 ÷ (1 + 7 ÷ 30) = 81.1%. With a 180 kg max that is about 146 kg. A single at RPE 10 is 100% by definition.
Other charts differ
Published RPE charts don’t all use the same numbers, and they differ most for singles and doubles. Use the chart your program was written with, and stay with one, so your numbers stay comparable week to week.
Rounded for the bar
Loads round to the nearest 0.5. To turn one into plates, use the plate calculator.
// WHY LIFTERS USE RPE //
A load that fits the day.
It adjusts set to set
Helms and colleagues describe the reps-in-reserve scale as a way to match loads to what a lifter can do on the day, set by set, and as possibly more precise near maximal loads.
It gets better with practice
Experienced benchers rated a true max at 9.86 on average against 9.35 for novices (Ormsbee et al., 2019). Rate every set and you will calibrate faster.
RPE or percentages?
Percentages are simpler to plan; RPE adapts to fatigue and good days. See RPE vs percentage training for when each fits, and RPE workout tracker apps for logging it.
// DIRECT ANSWERS //
Questions lifters ask.
What does RPE 8 mean?
About two reps left in the tank. On the reps-in-reserve scale used in strength training, RPE 10 is a maximal effort with nothing left, RPE 9 is one rep left, RPE 8 is two, and half points sit between them.
How do you convert RPE to a percentage of your max?
Add the reps in reserve (10 minus the RPE) to the reps you did and read the total as a rep max. With Epley, 5 reps at RPE 8 counts as 7 reps to failure, which is 1 ÷ (1 + 7 ÷ 30) = 81.1% of your one-rep max.
What is the difference between RPE and RIR?
They describe the same thing from two ends. RIR counts the reps you had left; RPE rates how hard the set was. On this scale RPE = 10 − RIR, so RPE 7 and 3 RIR are the same set.
How accurate is RPE?
It tracks effort well in trained lifters. In studies of the squat and bench press, RPE rose as bar speed fell (r = −0.88 for experienced squatters), and experienced lifters rated a true max closer to 10 than novices did (9.86 against 9.35 on the bench).
Why does a single drop so much from RPE 10 to RPE 9 with Epley?
Because Epley treats a single as 100% and a double as 93.8%, a big step at the very top of the chart. Brzycki puts a double at 97.2%. If your program gives heavy singles at RPE 8 or 9, compare both formulas and start conservatively.
Does IronLedger use RPE?
IronLedger logs RPE or RIR on every set, chosen per exercise, with decimals allowed. On its five load-and-go programs, an easy session (RPE 7 or below) adds 2.5 kg or lb next time and a hard one (RPE 9 or higher) holds the load. It does not convert RPE into percentages; that is what this page is for.
// SOURCES //
Where the maths comes from.
- Zourdos MC, et al. Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserve. J Strength Cond Res, 2016;30(1):267–275.
- 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.
- Ormsbee MJ, et al. Efficacy of the repetitions in reserve-based rating of perceived exertion for the bench press in experienced and novice benchers. J Strength Cond Res, 2019;33(2):337–345.
- Brzycki M. Strength testing: predicting a one-rep max from reps-to-fatigue. Journal of Physical Education, Recreation & Dance, 1993;64(1):88–90.
Log RPE or RIR on every set
IronLedger records RPE or RIR on each set, chosen per exercise, with the planned value as a hint. On its five load-and-go programs, how hard the last session was decides whether the load goes up or holds. Free, with no subscription.
Get IronLedger free on iOSUse it from an AI assistant
The same calculation is a free JSON API at /api/tools/rpe-target-load and a tool on the IronLedger MCP server, so an assistant can run it and link back to this page with your numbers.
// MORE TOOLS //
Other free calculators.
One rep max calculator
Your estimated 1RM from any set, with a percentage table and the load each rep count should allow.
Bench press calculator
Estimate your max bench from a set of reps, with bench-specific notes on what counts as a rep.
Plate calculator
Which plates go on each side of the bar, for any bar, in kg or lb, with the plates you actually own.