Strength calculator

RPE & Rest Calculator

Turn a logged set into an estimated 1RM, or turn a known 1RM into a target load for a given reps × RPE prescription. Includes between-set rest ranges by goal and effort.

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.

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.

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.

Full RPE → %1RM chart

Example: 5 reps at RPE 8 ≈ 81.1% of 1RM. Estimates get less reliable toward 10–12 reps — prefer heavier, lower-rep sets when tracking e1RM.

Percent of 1RM by reps and RPE
Reps109.598.587.576.56
1100%97.8%95.5%93.9%92.2%90.7%89.2%87.8%86.3%
295.5%93.9%92.2%90.7%89.2%87.8%86.3%85%83.7%
392.2%90.7%89.2%87.8%86.3%85%83.7%82.4%81.1%
489.2%87.8%86.3%85%83.7%82.4%81.1%79.9%78.6%
586.3%85%83.7%82.4%81.1%79.9%78.6%77.4%76.2%
683.7%82.4%81.1%79.9%78.6%77.4%76.2%75.1%73.9%
781.1%79.9%78.6%77.4%76.2%75.1%73.9%72.8%71.7%
878.6%77.4%76.2%75.1%73.9%72.8%71.7%70.7%69.6%
976.2%75.1%73.9%72.8%71.7%70.7%69.6%68.6%67.6%
1073.9%72.8%71.7%70.7%69.6%68.6%67.6%66.6%65.6%
1171.7%70.7%69.6%68.6%67.6%66.6%65.6%64.7%63.7%
1269.6%68.6%67.6%66.6%65.6%64.7%63.7%62.8%61.8%

Use with strength lifts

Pair RPE-based loading with consistent technique on the same lifts, then convert loads to plates or cross-check with a classic 1RM formula.