Estimate your 1RM from any set using the Epley and Brzycki formulas, then get a full %-of-1RM training load chart. Free, no signup.
The load you used for the set.
Between 1 and 12 — use a near-failure set.
| % 1RM | Load | Reps | Purpose |
|---|---|---|---|
| 100% | 212 lb | 1 | Max single |
| 95% | 201.5 lb | 2 | Heavy double |
| 90% | 191 lb | 3–4 | Strength |
| 85% | 180 lb | 5–6 | Strength |
| 80% | 169.5 lb | 7–8 | Strength / hypertrophy |
| 75% | 159 lb | 8–10 | Hypertrophy |
| 70% | 148.5 lb | 10–12 | Hypertrophy |
| 65% | 138 lb | 12–15 | Hypertrophy / endurance |
| 60% | 127 lb | 15–18 | Endurance |
| 55% | 116.5 lb | 18–20 | Endurance |
| 50% | 106 lb | 20+ | Warm-up / technique |
Your one-rep max (1RM) is the most weight you can lift for a single clean repetition of an exercise. It's the standard reference point for strength programming: nearly every structured plan — 5/3/1, Starting Strength, Texas Method, most powerlifting peaking blocks — prescribes working weights as a percentage of it. The problem is that actually testing a true 1RM is fatiguing and carries real injury risk, so coaches estimate it from a heavier set of a few reps instead.
This calculator runs the two most widely used estimators and averages them. Epley (1RM = weight × (1 + reps ÷ 30)) is a linear model first published by Boyd Epley, longtime strength coach at Nebraska. Brzycki (1RM = weight × 36 ÷ (37 − reps)), from Matt Brzycki, curves a little more steeply. At a single rep both return your input exactly; across 2–6 reps they agree closely, and averaging them smooths out their disagreement at higher rep counts.
Once you have an estimated 1RM, the load chart below converts it into every training intensity you're likely to program. The heavy rows (85–100%) are for strength and peaking; the middle rows (65–80%) are the classic hypertrophy range; the light rows (50–60%) cover technique, speed, and warm-up ramps. Pick the row that matches today's goal and load the bar accordingly. Weights are rounded to the nearest half unit so they map cleanly onto standard plates.
The real gains come from showing up consistently, not from one perfect session. Log a near-failure set each workout and track "strength session" as a daily habit in HabitBox — the free, on-device habit tracker for iOS and Android. One tap marks the session done, your streak grows, and the cue does the heavy lifting on the days motivation doesn't show up.
Note: estimated maxes are training tools, not guarantees. Always warm up thoroughly, use a spotter or safety pins for heavy attempts, and stop if a lift feels wrong. If you're new to a movement, build the percentages off a conservative estimate.
Estimation formulas are most accurate when the set you enter is in the 2–6 rep range and taken close to failure. Below about 10 reps the Epley and Brzycki formulas agree within a couple of percent. As reps climb past 10, the estimates diverge and tend to overpredict, because endurance and pacing start to matter more than pure strength. Treat the number as a reliable training anchor, not a guaranteed gym lift — your true max on any given day shifts with sleep, fuel, and warm-up.
Both convert a multi-rep set into a single-rep estimate, but they curve slightly differently. Epley (1RM = weight × (1 + reps ÷ 30)) is linear and tends to read a touch higher at high reps. Brzycki (1RM = weight × 36 ÷ (37 − reps)) curves more steeply and reads a touch lower as reps climb. At 1 rep both return your exact input. This tool averages the two so you get a balanced estimate instead of cherry-picking the one that flatters your ego.
Most strength programs prescribe work as a percentage of your 1RM. For pure strength, train in the 85–95% band (heavy sets of 2–6). For muscle growth (hypertrophy), the 65–80% band (sets of 8–12) is the sweet spot. Use 50–60% for technique work, speed work, and warm-up ramps. Pick the row that matches today's goal and load the bar to that weight.
Use a set of 3 to 6 reps taken within 1–2 reps of failure. That range gives the formulas the cleanest signal because the set is still strength-dominant rather than endurance-dominant. Avoid maxing out a true 1-rep attempt just to feed the calculator — the whole point of estimating is to skip the injury risk of a genuine max. Entering a grindy set of 5 is both safer and accurate enough for programming.
Re-estimate every 4–8 weeks, or whenever a working set starts feeling easier than the percentage chart predicts. As you get stronger your 1RM drifts up, so your old percentages get too light. The simplest habit is to log one near-failure set each session and recalculate when the numbers stop matching how the lift feels.
Knowing your numbers is step one — showing up is what moves them. HabitBox lets you track 'strength session' as a one-tap daily habit and watch the streak compound. Free, on-device, iOS + Android.
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