RPE vs RIR: what is the difference?

RPE (rate of perceived exertion) is how hard the set felt. RIR (reps in reserve) is how many reps you had left. They describe the same idea: how close you were to failure. A quick conversion is RPE = 10 - RIR (so RIR 0 ~ RPE 10, RIR 2 ~ RPE 8).

Why does my estimated 1RM jump?

Small changes in reps, effort rating, or technique can change the %1RM lookup and amplify the estimated 1RM (e1RM). Keep the exercise, rep range, and judging standard consistent. If your e1RM jumps more than ~5% week to week, verify with a lower-RPE set.

How accurate is RPE at high reps?

At 10-12 reps, fatigue and pacing make RPE harder to judge and chart-based %1RM less reliable. Treat high-rep e1RM as a rough estimate. For a cleaner estimate, use fewer reps (1-6) at a controlled RPE.

Free toolRPE to %1RMRIR to RPEMetric + imperial

Top Set to Backoff Sets Calculator

Use this RPE to percent 1RM calculator (RPE to %1RM chart) to estimate your one rep max (1RM) from a set at a given RPE or RIR.

Enter reps and load (lb or kg), then choose RPE (how hard it felt) or RIR (reps in reserve). RPE stands for rate of perceived exertion. You'll get:

Percent of 1RM (%1RM) for your set
Estimated 1RM (e1RM)
Next-week targets: top set at RPE 8 + 2 backoff sets at RPE 7

Note: Estimates are less reliable at 10-12 reps.

Methods & assumptions

This variant focuses on Top Set to Backoff Sets Calculator.

This RPE to percent 1RM calculator converts an RPE or RIR set into a percent of 1RM (%1RM) and an estimated 1RM (e1RM), then uses that e1RM to suggest next-week loading for a top set and backoff sets.

%1RM for your set: how heavy the set was relative to your estimated 1RM, based on the RPE chart.
Estimated 1RM (e1RM): the one-rep max implied by that set (not a tested max).
Next-week targets: suggested loads for a top set at RPE 8 plus 2 backoff sets at RPE 7 for your planned reps.

1) Convert RIR to RPE (if needed)

RPE = 10 - RIR

Example: RIR 2 is about RPE 8. Rule of thumb: RPE 10 ~ 0 RIR, RPE 8 ~ 2 RIR, and RPE 6 ~ 4 RIR.

2) Look up %1RM from the RPE chart

We use reps (1-12) and RPE (6.0-10.0) to get a %1RM value from the chart.

3) Calculate e1RM

e1RM = load / (%1RM / 100)

4) Generate next-week targets

target load = e1RM x (%1RM_target / 100)

Targets are a top set at RPE 8 and 2 backoff sets at RPE 7 (same reps as your planned rep target).

Example: 315 lb x 5 @ RPE 8.5 -> ~382.5 lb e1RM (82.4%1RM).

Chart source: standard Reactive Training Systems (RTS) RPE chart (chart version rts-v1).
Interpolation: linear between 0.5 RPE steps.
Rounding: nearest 2.5 lb (imperial) or 0.5 kg (metric).
High reps: estimates are less reliable at 10-12 reps. Use fewer reps to confirm if needed.
Sharing: inputs are encoded in the URL, e.g. ?reps=5&loadLb=315&rpe=8.5&plannedReps=5&chart=rts-v1

RPE to %1RM chart (RTS)

Source: Reactive Training Systems

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%	97.8%	95.5%	93.9%	92.2%	90.7%	89.2%	87.8%	86.3%
2	95.5%	93.9%	92.2%	90.7%	89.2%	87.8%	86.3%	85%	83.7%
3	92.2%	90.7%	89.2%	87.8%	86.3%	85%	83.7%	82.4%	81.1%
4	89.2%	87.8%	86.3%	85%	83.7%	82.4%	81.1%	79.9%	78.6%
5	86.3%	85%	83.7%	82.4%	81.1%	79.9%	78.6%	77.4%	76.2%
6	83.7%	82.4%	81.1%	79.9%	78.6%	77.4%	76.2%	75.1%	73.9%
7	81.1%	79.9%	78.6%	77.4%	76.2%	75.1%	73.9%	72.3%	70.7%
8	78.6%	77.4%	76.2%	75.1%	73.9%	72.3%	70.7%	69.4%	68%
9	76.2%	75.1%	73.9%	72.3%	70.7%	69.4%	68%	66.7%	65.3%
10	73.9%	72.3%	70.7%	69.4%	68%	66.7%	65.3%	64%	62.6%
11	70.7%	69.4%	68%	66.7%	65.3%	64%	62.6%	61.3%	59.9%
12	68%	66.7%	65.3%	64%	62.6%	61.3%	59.9%	58.6%	57.2%

Reps: 1

RPE 10100%

RPE 9.597.8%

RPE 995.5%

RPE 8.593.9%

RPE 892.2%

RPE 7.590.7%

RPE 789.2%

RPE 6.587.8%

RPE 686.3%

Reps: 2

RPE 1095.5%

RPE 9.593.9%

RPE 992.2%

RPE 8.590.7%

RPE 889.2%

RPE 7.587.8%

RPE 786.3%

RPE 6.585%

RPE 683.7%

Reps: 3

RPE 1092.2%

RPE 9.590.7%

RPE 989.2%

RPE 8.587.8%

RPE 886.3%

RPE 7.585%

RPE 783.7%

RPE 6.582.4%

RPE 681.1%

Reps: 4

RPE 1089.2%

RPE 9.587.8%

RPE 986.3%

RPE 8.585%

RPE 883.7%

RPE 7.582.4%

RPE 781.1%

RPE 6.579.9%

RPE 678.6%

Reps: 5

RPE 1086.3%

RPE 9.585%

RPE 983.7%

RPE 8.582.4%

RPE 881.1%

RPE 7.579.9%

RPE 778.6%

RPE 6.577.4%

RPE 676.2%

Reps: 6

RPE 1083.7%

RPE 9.582.4%

RPE 981.1%

RPE 8.579.9%

RPE 878.6%

RPE 7.577.4%

RPE 776.2%

RPE 6.575.1%

RPE 673.9%

Reps: 7

RPE 1081.1%

RPE 9.579.9%

RPE 978.6%

RPE 8.577.4%

RPE 876.2%

RPE 7.575.1%

RPE 773.9%

RPE 6.572.3%

RPE 670.7%

Reps: 8

RPE 1078.6%

RPE 9.577.4%

RPE 976.2%

RPE 8.575.1%

RPE 873.9%

RPE 7.572.3%

RPE 770.7%

RPE 6.569.4%

RPE 668%

Reps: 9

RPE 1076.2%

RPE 9.575.1%

RPE 973.9%

RPE 8.572.3%

RPE 870.7%

RPE 7.569.4%

RPE 768%

RPE 6.566.7%

RPE 665.3%

Reps: 10

RPE 1073.9%

RPE 9.572.3%

RPE 970.7%

RPE 8.569.4%

RPE 868%

RPE 7.566.7%

RPE 765.3%

RPE 6.564%

RPE 662.6%

Reps: 11

RPE 1070.7%

RPE 9.569.4%

RPE 968%

RPE 8.566.7%

RPE 865.3%

RPE 7.564%

RPE 762.6%

RPE 6.561.3%

RPE 659.9%

Reps: 12

RPE 1068%

RPE 9.566.7%

RPE 965.3%

RPE 8.564%

RPE 862.6%

RPE 7.561.3%

RPE 759.9%

RPE 6.558.6%

RPE 657.2%

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Learn more

Editorial policy & methodology

Reactive Training Systems (RPE system)

Rating of perceived exertion (overview)

Questions & Answers

Clear answers, so you can use this tool with confidence.

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