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RPE calculator
Enter a set you just did with its weight, reps and RPE, then the reps and RPE your program asks for next. The calculator estimates your one-rep max from that set and gives the load for the next one, plus a table of loads for 1, 3, 5, 8 and 10 reps at RPE 7, 8 and 9.
Example result
110kg
120kg
100 kg × 5 at RPE 8 means about 2 reps left in reserve.
| Set | RPE 9 | RPE 8 | RPE 7 |
|---|---|---|---|
| 1 rep | 115 kg | 112.5 kg | 110 kg |
| 3 reps | 110 kg | 105 kg | 102.5 kg |
| 5 reps | 102.5 kg | 100 kg | 97.5 kg |
| 8 reps | 95 kg | 92.5 kg | 90 kg |
| 10 reps | 90 kg | 87.5 kg | 85 kg |
RPE calculator examples
Four lifters, four different sets. Each one turns what they just did into the load for what the program asks next.
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Example 1
Top single, then back-off fives
A powerlifter whose program says: work up to a single at RPE 8.5, then 3 sets of 5 at RPE 7. The single moved at 140 kg.
- Weight lifted
- 140 kg
- Reps completed
- 1
- RPE of that set
- 8.5
- Next set: reps
- 5
- Next set: RPE
- 7
- 5 reps at RPE 7120 kg
- Estimated 1RM147 kg
The single sets the day's max, so the back-offs follow how strong the lifter is today, not on a good day last month. If the first five feels harder than RPE 7, drop one plate step for the rest.
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Example 2
A beginner moving up a notch
Two months into squatting, 185 lb for 6 reps with about 3 left. Next week's plan is 6 reps at RPE 8.
- Weight lifted
- 185 lb
- Reps completed
- 6
- RPE of that set
- 7
- Next set: reps
- 6
- Next set: RPE
- 8
- 6 reps at RPE 8190 lb
- Estimated 1RM234 lb
Same reps, one rep closer to failure, so the load goes up by a single plate step rather than a guess. Beginners tend to call sets harder than they are, so if 6 still feels easy at the new weight, it probably is.
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Example 3
Volume day for an older lifter
A 58-year-old woman who deadlifted 60 kg for 5 with maybe half a rep left, and wants sets of 8 at RPE 8 for the rest of the block.
- Weight lifted
- 60 kg
- Reps completed
- 5
- RPE of that set
- 9.5
- Next set: reps
- 8
- Next set: RPE
- 8
- 8 reps at RPE 852.5 kg
- Estimated 1RM69 kg
A hard set of 5 is a good test set: close to failure, few reps, so the estimate is sound. Sets of 8 with 2 in reserve keep the work productive while leaving room to recover between sessions.
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Example 4
A set too far from failure
A bench presser who did 225 lb for 10 easy reps, rated RPE 7, and whose next session calls for 5 reps at RPE 8.
- Weight lifted
- 225 lb
- Reps completed
- 10
- RPE of that set
- 7
- Next set: reps
- 5
- Next set: RPE
- 8
- 5 reps at RPE 8265 lb
- Estimated 1RM~315 lb
Ten reps plus 3 in reserve is 13 from failure, past where max estimates hold, so the calculator marks the 1RM as rough. Treat the target load as a ceiling: work up to it in steps, then re-enter the first heavy set of 5 for a sharper number.
Which sets give the best estimate
Heavy, low-rep sets close to failure. In a study of 70 men and women, a 5-rep max predicted the 1RM better than a 10- or 20-rep max, and the authors advised using no more than 10 reps. RPE ratings also get more accurate near failure: in a long squat set, lifters who called RPE 9 were off by about 2 reps, and those who called RPE 5 by about 5.
So the best input is a set of 1 to 6 reps at RPE 8 to 10, usually your top set of the day. Sets you rate RPE 6 or 7 still work, but the estimate is softer.
Using it for back-off sets
Many RPE programs prescribe a top set at a target RPE, then back-off sets at a lower one. Enter the top set as you did it and the back-off reps and RPE as the target. The load you get is tied to how the top set moved today, which is the point of training by RPE.
To see every rep and RPE combination at once, use the RPE chart. If you think in reps left rather than RPE, the RIR calculator answers the same question the other way round.
How the RPE calculator works
RPE becomes reps in reserve: RPE 10 is none left, RPE 9 is one, RPE 8 is two, and half steps are half a rep. Reps plus reps in reserve gives the reps you could have done to failure, which goes into Epley's formula in the form the RIRLift app uses, where a true single returns its own weight. The target load is the same formula run backwards.
Many RPE charts are adapted from Mike Tuchscherer's Reactive Training Systems table, which puts 5 reps at RPE 8 at 81.1% of max, so the same 100 kg set estimates 123.3 kg there and 120 kg here. From one set to another the two agree closely: 5 at RPE 8 to 3 at RPE 9 is 9.1% heavier here and 10.0% on that chart.
The estimated max is rounded to 0.5 kg or 1 lb, and the loads to 2.5 kg or 5 lb.
1RM = weight × (1 + (reps + (10 − RPE) − 1) ÷ 30)
load = 1RM ÷ (1 + (target reps + (10 − target RPE) − 1) ÷ 30)
100 × (1 + (5 + 2 − 1) ÷ 30) = 120 kg
120 ÷ (1 + (3 + 1 − 1) ÷ 30) = 109.1, shown as 110 kgMake it fit you
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Rate the set the moment you rack it
Decide how many reps you had left while the last rep is still fresh, before rest and the next set blur it.
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Use half steps when you're unsure
RPE 8.5 means maybe 2 left, surely 1. It's more honest than rounding to a whole number, and the calculator treats it as 1.5 reps in reserve.
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Recalculate every session
The point of RPE is that the load follows the day. Enter today's top set rather than reusing last week's numbers.
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Round to the plates you have
Loads round to 2.5 kg or 5 lb. With fractional plates, round down to the nearest 1 kg or 2.5 lb instead, and the target RPE will land a little lower.
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Use it for any lift
The formula is the same for squats, bench, deadlifts and presses. Keep one estimated max per lift, because each one sits at a different share of your strength.
Questions
What is RPE in lifting?
RPE, rating of perceived exertion, scores how hard a set was from 1 to 10, where 10 is no reps left. What is RPE in lifting covers the full scale.
Is RPE 8 the same as 2 reps in reserve?
Yes, on the scale lifters use: RPE 10 is 0 reps in reserve, RPE 9 is 1, RPE 8 is 2. RPE vs RIR explains when each is easier to log.
How accurate is an RPE calculator?
As accurate as the set and the rating behind it. Lifters rate sets close to failure most accurately, and estimates from 10 reps or fewer hold up best, so a heavy set of 3 to 5 at RPE 8 to 10 gives the most reliable number.
How do I convert RPE to a percentage of 1RM?
Add the reps to the reps in reserve, then look up that rep count's percentage. The RPE chart has every combination from 1 to 12 reps.
Why does the RPE scale stop at 6?
Below RPE 6 you are more than 4 reps from failure, and nobody can count that far ahead reliably. In one squat study, sets called RPE 5 were off by about 5 reps.
What RPE should I train at?
It depends on the lift and the goal: big lifts like the squat usually stay 2 to 3 reps from failure (RPE 7 to 8), while isolation work can go closer. How to use RIR sets targets by goal and across a training block.
Related calculators and templates
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RPE chart
Every reps and RPE combination as a percentage of your max.
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RIR calculator (reps in reserve)
How many reps a set left, checked against your max.
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One-rep max calculator
The same estimate for any lift, entered as reps in reserve.
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Warm-up calculator
The sets that get you to your top set without wasting it.
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RPE vs RIR
Two ways to rate a set, and which is easier to log honestly.
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How to use RIR
Effort targets by goal, and how to progress them across a block.
Sources
- Reynolds, Gordon and Robergs (2006), prediction of 1RM strength from multiple repetition maximum testing
- Zourdos et al. (2021), proximity to failure and reps per set influence the accuracy of RIR-based RPE
- Zourdos et al. (2016), a resistance training-specific RPE scale measuring repetitions in reserve
- Hardy, RPE calculator and chart adapted from the Reactive Training Systems table
- Fitness Volt, RPE chart based on Mike Tuchscherer's table
Let every set set the next one
Log the reps you had left (RPE 8 is 2 in reserve) and RIRLift keeps each lift's estimated max current from your best working set, then works out the next set's load from the one you just did.
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