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Strength calculator

RPE & Rest Calculator

Frequently asked questions

What does RPE mean in lifting?
RPE estimates effort on a set. Roughly, RPE 10 is no reps left, RPE 9 is about one rep in reserve, RPE 8 is about two, and so on.
How do I convert RPE to percent of 1RM?
Use a reps × RPE chart to estimate %1RM for programming. Charts are guidelines — bar speed, sleep, and exercise skill still change the real load.
How long should I rest between hard sets?
Heavy compounds often need about 2–3+ minutes. Shorter rests that cut bar speed usually cut strength quality too. Accessories can often use shorter rests.

How the RPE chart works

This page uses a widely cited Reactive Training Systems / Tuchscherer-style chart that maps reps (1–12) and RPE (6–10) to a percentage of 1RM. RPE here is anchored to reps in reserve: RIR ≈ 10 − RPE (RPE 8 ≈ 2 reps left).

Estimate mode uses e1RM = weight ÷ (%1RM / 100). Plan mode uses target load = 1RM × (%1RM / 100). Percentages are population averages — adjust for the lift, fatigue, and how the set actually felt.

RPE calculator form

RPE calculator results

Estimated 1RM
123.3 kg

5 reps @ RPE 8 ≈ 81.1% of 1RM (~2 RIR).

% of 1RM

81.1%

Reps in reserve

~2

From load

100.0 kg

Between-set rest times

Rest is not a single formula — it depends on the goal, proximity to failure, and whether the next set needs power or only completion. Use these conservative ranges as a starting point, not a medical prescription. For a full walkthrough, see How Long to Rest Between Sets.

By training goal

2–5 minutes

Longer rests (often 3–5 min) for heavy low-rep sets so bar speed and technique recover.

By current RPE (8)

2–3.5 minutes

Classic working-set intensity; rest long enough to keep later sets quality.