Bassam Mallick
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1-Rep Max

What's your one-rep max?

6 formulas in parallel, optional RIR/RPE mode (more accurate than rep count), strength standards by bodyweight + sex, complete percentage table, and predicted 3/5/8/10/12 rep-max loads — all from one sub-maximal set.

Units

Standard rep-count estimate. Assumes set was taken near failure.

Estimated 1RM · Bench press

Median of context-appropriate formulas

±2.0 kg
69.9kg

From 5 reps at the given weight

6-formula comparison

Highlighted: best fit for your rep count

Epley70.0 kg
Brzycki67.5 kg
Lombardi70.5 kg
O'Conner67.5 kg
Mayhew71.4 kg
Wathan69.9 kg

Strength tier · Bench press

Untrained
Untrained
56.3Novice
75.0Intermediate
112.5Advanced
150.0Elite
187.5

Next tier: Novice at 75.0 kg — 5.1 kg to go.

Standards from Strength Level + ExRx data. Multipliers of bodyweight. Different sources vary; treat as directional, not absolute.

Training percentages

% 1RMRepsZoneLoad
100%1Testing69.9 kg
95%2Max strength66.5 kg
90%3-4Strength63.0 kg
85%5-6Strength / power59.5 kg
80%7-8Hypertrophy / strength56.0 kg
75%9-10Hypertrophy52.5 kg
70%11-12Hypertrophy / endurance49.0 kg
65%13-15Endurance45.5 kg
60%16-20Endurance / warm-up42.0 kg
50%20+Speed / warm-up35.0 kg

Predicted rep-max loads

3 RM

65.1

kg

5 RM

60.9

kg

8 RM

56.0

kg

10 RM

52.5

kg

12 RM

49.0

kg

Target loads for your 3/5/8/10/12-rep max sets at RPE 9 (1 RIR). Useful for programming 5×5, working sets, and AMRAP estimation.

When 1RM testing is safe

Tested vs estimated max

For beginners (under ~6 months of consistent training) — don't test your 1RM. Research shows only ~57% of novices actually hit RPE 9+ on what they call their max; they tend to lift 42-57% of their true 1RM. An estimated max from a 5-rep set is safer and more accurate.

For intermediate-plus lifters: warm-up at 40-60% × 5, 70% × 3, 80% × 2, 90% × 1, then 3-7 maximum singles with 5%/10-20% jumps (upper/lower body) and 3-5 minutes rest. Spotters mandatory on squat and bench.

Why estimates vary

Formula accuracy

Each formula has a sweet-spot rep range. Epley is accurate 2-10 reps but drifts high above 8. Brzycki is conservative 3-10. Wathan handles 2-15 well. Mayhew is best 3-10 (also extends to 20). O'Conner is the most conservative.

We pick the median of context-appropriate formulas for your rep count (Epley/Brzycki/Wathan for 1-5 reps, Brzycki/Mayhew/Wathan for 6-10, Mayhew/Wathan for 10+). That's more honest than picking one and pretending it's perfect.

RIR / RPE mode

Why RIR beats rep count

Six reps at RPE 8 ≠ six reps at RPE 10 (77.5% vs 87.5% of 1RM, per Tuchscherer's RTS chart). Rep count alone hides 10% of intensity. Research shows reps-at-percentage varies massively between lifters — at 70% 1RM, trained athletes have done anywhere from 6 to 26 reps.

RIR (reps in reserve) captures how hard the set was, not just how many reps. RIR mode in the tool uses the Tuchscherer/RTS lookup — more accurate than any rep-only formula once you can honestly gauge your remaining reps.

Lift-specific caveats

Deadlift underestimates, bench over-estimates

Reps-to-failure curves differ by lift. Deadlifts tend to be grindy — the last rep at "true failure" usually comes when bar speed has dropped 70%+. Bench presses fail sharper. So a 5RM deadlift estimate systematically under-shoots true 1RM; a 5RM bench over-shoots slightly.

For deadlift maxes, lean toward the higher end of the formula range; for bench, lean toward the median. Lift-specific coefficient tables (NSCA, ExRx) outperform any universal formula.

Form

Form breakdown invalidates the math

The formulas assume each rep is the same movement. Grinding reps with hip rise on squat, knee cave on deadlift, or back rounding aren't the rep the formula models. If form changed in the last reps, count fewer reps for the estimate — better still, retest with stricter form.

Lifting safety

Always warm up before max attempts. Use a spotter or safety bars on squat and bench. Cap your estimated 1RM around 95% of test for safety. If you have spinal, joint, or cardiovascular conditions, consult a coach or physio before max testing.

How it works

6 formulas in parallel: Epley · Brzycki · Lombardi · O'Conner · Mayhew · Wathan. Each is accurate in a specific rep range — we pick the median of context-appropriate formulas for your rep count (low reps: Epley + Brzycki + Wathan; mid: Brzycki + Mayhew + Wathan; high: Mayhew + Wathan).

RIR / RPE mode: Reps alone don't capture how hard the set was — 6 reps at RPE 8 vs RPE 10 differ by 10% of 1RM (77.5% vs 87.5%). RIR mode uses the Tuchscherer/RTS lookup chart, which captures intensity directly. More accurate once you can honestly gauge reps in reserve.

Strength standards from Strength Level + ExRx — tier (Untrained / Novice / Intermediate / Advanced / Elite) by bodyweight + sex + lift, with the next-tier threshold shown so you know exactly how much to add.

Training percentage table with rep ranges and zone (Hypertrophy, Strength, Max strength, etc) plus a rep-max targets grid (your 3RM, 5RM, 8RM, 10RM, 12RM loads at RPE 9).

Frequently asked questions

  • Which formula should I trust?

    Each has a sweet-spot rep range. Epley is accurate 2-10 but drifts high above 8. Brzycki is conservative 3-10. Wathan handles 2-15 well. Mayhew is best 3-10. The tool picks the median of context-appropriate formulas for your specific rep count and highlights which formulas it used. That's more honest than picking one and pretending it's perfect.

  • Why is RIR mode more accurate than rep count?

    Six reps at RPE 8 ≠ six reps at RPE 10 — that's 77.5% vs 87.5% of 1RM (Tuchscherer/RTS chart). Rep count alone hides 10% of intensity. Research shows reps-at-percentage varies massively between lifters: at 70% 1RM, trained athletes have completed anywhere from 6 to 26 reps. RIR captures how hard the set actually was.

  • How do I know my RIR honestly?

    Rule of thumb: if you can't tell whether you had 1 or 3 reps in the tank, the set was probably easier than you think. Calibrate by occasionally pushing a set to failure — you'll feel the difference in bar speed (slowing 30%+) and effort (max grimace, mouth open). RIR 0-2 sets feel grindy; RIR 4+ sets feel relatively snappy.

  • Should I test a true 1RM?

    Beginners (under ~6 months of consistent training): no — research shows only ~57% of novices actually hit RPE 9+ on what they call their max, and the injury risk isn't worth it. Estimated max from a 5-rep set is safer and more accurate. Intermediates and up: yes, every 12-16 weeks. Warm-up ramp 40-60-80-90% then 3-7 max singles with 5-10% jumps and 3-5 min rest. Spotters mandatory.

  • Why are deadlift and bench estimates different?

    Reps-to-failure curves differ by lift. Deadlifts tend to be grindy — the last rep at failure comes when bar speed has dropped 70%+. Bench presses fail sharper. So a 5RM deadlift estimate systematically under-shoots true 1RM; a 5RM bench can over-shoot slightly. Lift-specific calibration matters — lean toward the higher end for deadlift, median for bench.

  • What if my form breaks down on the last reps?

    Don't count those reps. The formulas assume each rep is the same movement. Grinding reps with hip rise on squat, knee cave on deadlift, or back arching on bench aren't the rep the formula models. Either count fewer reps for the estimate, or retest with stricter form. Form-broken estimates are noise.

  • How often should I retest my 1RM?

    For programming purposes — every 4-6 weeks via this tool from a moderate RIR set. For true tested maxes — every 12-16 weeks at most, typically at the end of a strength block. Your e1RM (estimated 1RM) will drift up as you get stronger; that's the trend that matters more than any single test number.