What 1RM and 5RM mean
1RM is the maximum weight you can lift for 1 rep. 5RM is the maximum weight you can lift for 5 reps. This tool estimates those (and more) from sets you’ve already performed.
1RM & 5RM Calculator
Enter any 2–3 rep max points (1–20 reps). We fit your curve and estimate your full 1–20 rep max profile.
How this calculator works
Add 2–3 “rep max points” from recent sets. We fit your personal load–rep curve and estimate your 1–20 rep max profile.
What is a “rep max point”?
A rep max point is one heavy set written as “reps × weight”. Use sets taken close to failure (about 0–3 reps in reserve).
Examples: 5 reps × 80 kg
10 reps × 65 kg
Why 2–3 points is better than 1
- One set can be noisy (fatigue, technique, bad day).
- Two or three sets let us fit your curve more reliably.
- Best accuracy comes from different rep ranges (e.g., 4–6 and 10–12).
What “learn curve” does
Your strength doesn’t drop in a straight line as reps increase — everyone has a slightly different relationship between load and reps. We use your points to estimate that relationship, then generate predicted max weights for 1–20 reps.
The “5RM” output is simply the predicted max weight at 5 reps on your curve.
Units & exercise selection
- Pick the lift first (bench, squat, deadlift, etc.).
- Choose kg or lb — then keep all inputs consistent.
- Using the correct lift matters because technique and rep endurance can differ by exercise.
Tips for the most accurate results
- Use sets done within the last 2–4 weeks.
- Use good form and consistent depth/ROM.
- Avoid “bounce reps” or partial reps when entering points.
- Enter weights you truly hit at the listed reps (no spotter assistance).
Limitations & context
- Estimates can be off if your sets were far from failure.
- High-rep endurance varies a lot between people, especially beyond 12–15 reps.
- Fatigue, sleep, and recovery can shift performance day to day.
How to use the numbers in training
Use your estimated 1RM as a reference point — then pick working weights as a percentage.
Strength focus: ~80–90% of 1RM
Hypertrophy focus: ~60–80% of 1RM
Technique / speed: lighter loads with perfect reps
Quick workflow
Choose lift
Set kg/lb
Add 2–3 points
Learn curve
Use 1–20RM outputs
If your predicted numbers look unrealistic, re-check: (1) reps were truly close to failure, (2) input units, and (3) you used at least two different rep ranges.
Mini FAQ
How accurate is this 1RM estimate?
It’s usually very solid when your inputs are honest sets taken close to failure (about 0–3 reps in reserve) and you enter 2–3 rep max points across different rep ranges (e.g., 4–6 reps and 10–12 reps). If you only enter one point, accuracy can drop because one set can be noisy (fatigue, form, bad day).
What reps should I use for my 2–3 points?
Aim for different rep ranges between 1–20 reps. A good combo is: 3–6 reps (heavier) plus 8–12 reps (moderate). Avoid entering three points that are all extremely close (e.g., 8, 9, 10 reps) — spread improves the curve fit.
Why does my predicted 10–20RM look “off”?
High-rep performance depends heavily on muscular endurance, pacing, and technique efficiency. If your input sets were far from failure, had inconsistent depth/ROM, or were affected by cardio fatigue, the higher-rep predictions can shift. For best results, include at least one point above 8 reps if you care about the 10–20RM region.
Can I use dumbbells or machines?
Yes — the math still works. Just keep your inputs consistent (same equipment and setup), and treat the result as a reference for that specific movement. Dumbbells and machines can differ from barbell numbers, so don’t compare across variations as if they’re the same lift.
Should I train using my estimated 1RM?
Use it as a reference, not a dare. Most training is better based on percentages and/or reps-in-reserve. If your estimated 1RM is changing week to week, focus on trend direction rather than one “perfect” number.
Have more questions? Visit the full FAQs.