Free effort calculator
RPE and RIR calculator
Convert lifting RPE to reps in reserve, then estimate a rough one-rep max from load, completed reps, and the reps you had left.
Reviewed March 5, 2026
Set effort estimate
Reps in reserve
2 RIR
Effective rep max
7 reps
Completed reps plus estimated reps remaining
Adjusted e1RM
228.2 lb
A rough Epley estimate
What this result means
On the common resistance-training scale, RIR is approximately 10 minus RPE. This tool also treats completed reps plus estimated reps remaining as an effective rep-max set to produce a rough estimated 1RM.
RIR ≈ 10 − RPE. Adjusted Epley e1RM = weight × (1 + (reps + RIR) ÷ 30).
RPE and RIR describe effort
RPE 10 means maximal effort with no good reps remaining. RPE 9 suggests about one rep remained; RPE 8 suggests about two.
The conversion is a practical convention, not a sensor reading. Round honestly and use the same scale over time.
Why the estimate has uncertainty
Research suggests RIR can be reliable, yet accuracy varies with load and experience. Lighter, higher-rep sets are generally harder to judge.
Use the output to compare similar sets and guide discussion, not to claim an exact maximum.
Frequently asked questions
What is RPE 8 in RIR?
Approximately 2 reps in reserve.
What is RPE 9.5?
It usually means about zero to one rep remained—roughly 0.5 RIR.
Is RPE subjective?
Yes. It becomes more useful when calibrated through repeated training and occasional safe checks.
Sources and assumptions
Effort is part of the set
Help your coach distinguish heavy from hard.
Log RPE, RIR, or a plain-language effort note with LogFast so similar loads can be interpreted against how the work actually felt.
More free tools
One-rep max calculator
Estimate your one-rep max from weight and reps using Epley and Brzycki formulas, then see practical training percentages.
Barbell plate calculator
Enter a target barbell weight and see which standard plates to load on each side for common pound or kilogram bars, including any remainder.
Workout volume calculator
Calculate lifting volume load, total reps, and weekly tonnage from sets, reps, weight, and training frequency.