RPE to percentage
Five reps at RPE 8 means you had two left. Turn that into a percentage of your max, and if you add the weight, an estimated max too.
Your details
5 reps at RPE 8
81%
of your one rep max, roughly
- Reps left in reserve2
- Counts like a set of7 to failure
- Estimated max from 100 kg123.3 kg
- Next: 3 reps at RPE 886% of max, about 105 kg (rounded to your plates)
RPE 10 means nothing left, RPE 8 means two more reps were there. New lifters tend to underestimate what is left, so treat early RPE scores with a pinch of salt.
Sharp pain, a pop, or pain that lingers after a session is a reason to stop and see a GP or physio. Chest pain or feeling faint while lifting: stop, and call 999 if it does not pass.
The working
5 reps at RPE 8
Two reps were left, so the set counts like 7 reps to failure. Epley says 1 ÷ (1 + 7 ÷ 30) = 81% of your max. At 100 kg that puts your max near 123 kg.
The scale
Reps in reserve
This RPE scale (Zourdos and colleagues, 2016) ties each number to reps left: 10 is none, 9 is one, 8 is two. It works best once you have a few months of lifting behind you.
Using RPE
Good habits
- Rate the set straight after it ends
- Film a set now and then to check honesty
- Most work at RPE 7 to 9
- Save RPE 10 for rare tests
Next set
Load for a planned set
From the same estimated max we work out a load for your next set. 3 reps at RPE 8 counts like 5 reps to failure: 1 ÷ (1 + 5 ÷ 30) = 85.7% of 123.3 kg = 105.7 kg, rounded to the smallest plate pair: 105 kg. This is the usual way RPE based programmes set the day's top set, and if the first set felt harder than planned, it lowers the next one for you.
Read with care
What this cannot tell you
- BeginnersNew lifters often guess reps left badly.
- High repsAbove about 10 reps the link gets loose, so this page stops at 10.
- Every liftIt is a guide, not a lab test.
Questions
Common questions
What does RPE 8 mean?
You could have done about two more reps.
What percentage is 5 reps at RPE 8?
About 81% of your max.
Is RPE better than percentages?
It adjusts for good and bad days; many lifters use both.
Sources
- Zourdos MC et al. A resistance training specific RPE scale measuring repetitions in reserve. J Strength Cond Res 2016
- LeSuer DA et al. The accuracy of prediction equations for estimating 1-RM performance in the bench press, squat and deadlift. J Strength Cond Res 1997;11(4):211-3
- NSCA: Essentials of Strength Training and Conditioning, 4th edition
Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.
Before you push on
New to exercise, or got a heart, lung or joint condition? Have a word with your GP or practice nurse first. Stop and get help if you feel chest pain, faintness or unusual breathlessness, and call 999 if it is severe.
Related
Related calculators
- Reps in reserve calculatorThe weight that leaves 2 reps in reserve.Open
- Training percentage calculatorPlan percentages turned into plates.Open
- One rep max calculatorYour 1RM from a hard set, no max out needed.Open
- Percentage of your max calculatorThe weight on the bar as a share of your max.Open
- Deload week calculatorYour next easy weeks, dated.Open
- Warm up set calculatorA ramp to your working weight.Open