Free Live Calculators

RPE Calculator — Estimate 1RM & Find Training Weights

Calculate estimated 1RM from RPE, find target weights for any rep/RPE combo, and plan backoff sets using the Tuchscherer RTS chart.

How to Use This Calculator

  1. 1

    Choose a mode

    Estimate 1RM: enter your lift, reps, and RPE to calculate your estimated max. Find Weight: enter your known 1RM and target reps/RPE to get the weight to put on the bar. Backoff Set: enter your top set to auto-calculate the appropriate backoff weight.

  2. 2

    Select lbs or kg

    Toggle between lbs and kg. The calculator rounds to the nearest 2.5 lbs or 1.25 kg — standard barbell increments.

  3. 3

    Enter reps and RPE

    Select reps (1–12) and RPE (6–10 in 0.5 increments). RPE 8 = could have done 2 more reps; RPE 10 = true max effort. The full RTS reference table shows percentages for every rep/RPE combination.

  4. 4

    Read results and reference table

    Results show estimated 1RM, percentage of 1RM used, and reps in reserve. Click 'Show full RPE reference table' to see the complete Tuchscherer RTS chart with your current input highlighted.

What Each Value Means

RPE (Rate of Perceived Exertion) (1–10 scale)
In powerlifting, a 1–10 scale describing effort. RPE 10 = maximum effort, nothing left. RPE 8 = 2 more reps were possible. Half-point values (e.g., 8.5) indicate 'between 1 and 2 reps in reserve.' The scale was adapted for strength sports by Mike Tuchscherer from Gunnar Borg's original exercise science scale.
Estimated 1RM (e1RM) (lbs or kg)
The predicted maximum weight you could lift for exactly one rep, derived from a submaximal effort using the RTS percentage table. e1RM = weight lifted / (RPE percentage / 100). This is an estimate — actual tested 1RMs may differ by ±5% due to individual variation, movement pattern fatigue, and neural factors.
RIR (Reps in Reserve) (reps)
The number of additional reps you could have performed before reaching failure. RIR = 10 − RPE. RIR 0 = max effort (RPE 10), RIR 2 = could have done 2 more (RPE 8). RIR is preferred in hypertrophy research; RPE is the standard term in powerlifting programming.

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Frequently Asked Questions

What does RPE mean in powerlifting?
RPE (Rate of Perceived Exertion) in powerlifting uses a 1–10 scale where 10 means you lifted your absolute maximum — nothing left in the tank. RPE 9 means one more rep was possible, RPE 8 means two more reps, and so on. Half-point increments (e.g., RPE 8.5) indicate 'between 1 and 2 reps in reserve.' This system lets coaches prescribe intensity without needing a tested 1RM, and allows daily adjustment based on how you actually feel.
What is the difference between RPE and RIR?
RIR (Reps in Reserve) is the number of reps you could have added before failure. RPE and RIR are directly related: RIR = 10 − RPE. RPE 8 = 2 RIR (two more reps possible), RPE 9 = 1 RIR, RPE 10 = 0 RIR (all-out max effort). RPE is the older, more common term in powerlifting; RIR is preferred in hypertrophy/bodybuilding contexts. Functionally they encode the same information.
How accurate is the RTS RPE chart for estimating 1RM?
The Tuchscherer RTS chart is accurate within ±5% for most trained lifters on compound movements (squat, bench, deadlift). Accuracy decreases at higher reps (8+) because fatigue compounds in ways that diverge between individuals. The chart works best for reps 1–5 at RPE 7–10. For absolute beginners, RPE perception is unreliable until ~6 months of training. The calculator is most useful as a training guide, not for setting competition attempts.
What is a good training RPE for strength vs hypertrophy?
For maximum strength development: RPE 8–9 on main compound lifts (2–1 reps in reserve), with occasional RPE 10 attempts on peak weeks. For hypertrophy: RPE 7–9 across higher rep ranges (6–12 reps). Going to RPE 10 on every set accelerates fatigue accumulation and increases injury risk without proportional strength gains. Most evidence-based powerlifting programs prescribe primary lifts at RPE 8–8.5 in the accumulation phase, building to 9–10 in the peaking phase.
How do I use RPE for backoff sets?
After a top set (e.g., 3 reps @ RPE 9), backoff sets are prescribed at a lower RPE using the same or different rep count: e.g., 4×5 @ RPE 7. Use the Backoff Set mode: enter your top set weight, reps, and RPE to estimate your 1RM, then enter the backoff reps and RPE. The calculator rounds to the nearest 2.5 lbs (1.25 kg) increment for practical loading.