One Rep Max Calculator —
Bench, Squat & Deadlift
Calculate your one rep max using 6 proven formulas — Brzycki, Epley, Lander, Lombardi, Mayhew, and O'Conner. Works for bench press, squat, deadlift, overhead press, pull ups, and more. Includes a full training percentage breakdown — the most useful output any 1RM calculator can show you.
Best accuracy at 3–6 reps
Bench Press
Estimated One Rep Max (average of 6 formulas)
Formula Breakdown
| Formula | 1RM Estimate |
|---|---|
| Brzycki | — |
| Epley | — |
| Lander | — |
| Lombardi | — |
| Mayhew | — |
| O'Conner | — |
| Average | — |
Training Percentage Breakdown
Use these weights to programme every training zone from your 1RM result.
| % of 1RM | Weight (kg) | Reps | Training Zone |
|---|---|---|---|
| 95% | — | 1–2 | Max Strength |
| 90% | — | 2–3 | Strength |
| 85% | — | 3–5 | Strength |
| 80% | — | 4–6 | Strength / Power |
| 75% | — | 6–8 | Hypertrophy |
| 70% | — | 8–10 | Hypertrophy |
| 65% | — | 10–12 | Hypertrophy |
| 60% | — | 12–15 | Hypertrophy / Endurance |
| 55% | — | 15+ | Endurance |
Track these exact weights in Sleet. It'll show you your last session's numbers the moment you need them.
Download Sleet FreeOne Rep Max Calculator Formula — How It Works
Every one rep max calculator formula takes the same two inputs — weight lifted and reps completed — and produces an estimate of the maximum you could lift for a single rep. This calculator runs all six major formulas simultaneously and averages the results, which research shows is more accurate than relying on any one formula alone.
When reps = 1, all formulas return the entered weight as the 1RM — no estimation needed.
Why averaging formulas is more accurate
Each formula was derived from different study populations and rep ranges. Brzycki tends to underestimate at higher reps. Lombardi tends to overestimate. Epley is the most commonly cited. By averaging all six, random errors in individual formulas cancel out, giving you a more reliable centre estimate.
Why accuracy drops above 10 reps
All 1RM formulas assume a linear relationship between reps and percentage of max. This holds reasonably well from 1–10 reps. Above 10, individual differences in muscle fibre composition, muscular endurance, and fatigue resistance cause the formulas to diverge significantly from each person's actual 1RM. For the most accurate estimate, use a working set of 3–6 reps at near-maximal effort.
Exercise-Specific One Rep Max Calculators
Bench Press One Rep Max Calculator
The bench press one rep max calculator is the most searched 1RM tool — and for good reason. Bench press 1RM is the primary upper-body strength benchmark in most gyms. Note that grip width affects your number: a wider grip typically produces a slightly higher 1RM due to reduced range of motion. Paused bench reps give a more accurate reflection of raw strength than touch-and-go reps. A typical intermediate lifter (2+ years training) bench presses between 100–140 kg (220–310 lbs).
Squat One Rep Max Calculator
The squat one rep max calculator must account for the fact that squat technique significantly affects the number. High-bar squat 1RMs are typically 5–10% lower than low-bar squat 1RMs for the same lifter, because low-bar mechanics allow more posterior chain involvement. Depth matters — a parallel squat has a different 1RM than a half squat. If you train with a belt, your belted 1RM will be 5–15% higher than beltless. Enter the numbers from the specific variation you want to track.
Deadlift One Rep Max Calculator
For most people, the deadlift 1RM is the highest of the big three lifts — it's common to deadlift 20–40% more than you squat. The conventional vs sumo distinction matters: sumo often allows a higher 1RM for lifters with the right hip structure due to the shorter range of motion. Using straps removes grip as a limiting factor, so a strapped deadlift 1RM will typically be higher than a double-overhand or mixed-grip 1RM. Enter the number relevant to your competition standard or training goal.
Incline Bench Press One Rep Max Calculator
Your incline bench press one rep max is typically 80–85% of your flat bench 1RM. The incline angle (usually 30–45°) shifts more of the load to the anterior deltoids and upper pectorals, reducing how much the triceps and lower chest contribute. A steeper angle reduces the 1RM further. Use the incline bench 1RM calculator to set appropriate working weights for upper chest development — running 70–80% of your incline 1RM for 6–10 rep sets is the most effective hypertrophy range.
Pull Ups One Rep Max Calculator
The pull ups one rep max calculator works differently to barbell exercises. Your baseline is bodyweight — if you can complete a single pull up, your 1RM is at minimum your bodyweight. To calculate a weighted pull up 1RM, add the weight from your belt or vest to your bodyweight and enter the total as the weight. For example, if you weigh 80 kg and used a 20 kg belt, enter 100 kg. Use this to programme weighted pull ups at appropriate percentages for strength or hypertrophy work.
How Accurate Is a One Rep Max Calculator?
A well-constructed one rep max calculator is accurate to within 5% for most lifters when based on a set of 3–6 reps at near-maximal effort. This is close enough to programme all training zones reliably.
- 3–6 reps: most accurate range — estimation error is typically under 5%
- 7–10 reps: reasonable accuracy — error increases to 5–10%
- 10+ reps: significantly less accurate — individual endurance capacity dominates the result
Individual variation is the main source of error. Some lifters have a higher proportion of slow-twitch muscle fibres and perform disproportionately well at higher reps relative to their 1RM. Others are fast-twitch dominant and drop off quickly above 3–5 reps. Neither is wrong — they just respond differently to the same formula.
Averaging six formulas (as this calculator does) is the most reliable approach available outside of a strength-testing lab. It reduces the impact of the outlier formulas and gives you a centre estimate that holds up across different body types and training backgrounds.
Using Your 1RM for Progressive Overload
Knowing your 1RM is only useful if you use it to structure your training. Here's how:
- Calculate your 1RM using this calculator from a working set of 3–6 reps
- For hypertrophy (muscle growth): train at 70–80% of 1RM for sets of 6–10 reps
- For strength: train at 80–90% of 1RM for sets of 3–5 reps
- Progress: add 2.5–5 kg to your working sets every 1–2 weeks
- Recalculate: run the 1RM calculator again every 4–6 weeks to track your strength progress
The training percentage table in this calculator shows your exact working weights for every zone. You don't need to do the maths manually — just use the table after every recalculation.
Sleet tracks this automatically so you never have to remember. Your last session's weights are visible the moment you open the app. Download free on Android →
One Rep Max Calculator — FAQ
What is a one rep max calculator?
A one rep max calculator estimates the maximum weight you can lift for a single repetition. You enter a weight and rep count from any working set, and the calculator uses proven formulas to estimate your 1RM — no all-out max attempt required.
How accurate is a one rep max calculator?
Most accurate at 3–6 reps, where estimation error is typically under 5%. Accuracy drops above 10 reps as individual endurance capacity becomes a larger factor than raw strength. Using an average of six formulas, as this calculator does, reduces error further.
What is the best formula for one rep max?
No single formula is universally best. Brzycki works well at low reps, Epley is the most widely cited, and Mayhew uses exponential decay for better behaviour at higher reps. Averaging all six formulas — as this calculator does — consistently outperforms any individual formula.
How do I calculate one rep max for bench press?
Select Bench Press in the exercise dropdown, enter the weight on the bar, and the number of reps you completed on your final working set. Click Calculate. The result is your estimated bench press 1RM, along with a table of weights for every training percentage.
How do I calculate one rep max for squat?
Select Squat from the dropdown. Enter the weight and reps from a working set — ideally your last heavy set of 3–5 reps at near-maximal effort. The calculator will estimate your squat 1RM and show working weights for strength, power, and hypertrophy zones.
How often should I test my one rep max?
Recalculate every 4–6 weeks using a heavy working set — there's no need to attempt a true max effort each time. This gives you a consistent progress marker without the fatigue and injury risk of regular max attempts.
Can beginners use a one rep max calculator?
Yes. Beginners can use it to set starting weights and track early strength gains. Focus on good technique first — then use the training percentage table to find appropriate weights for your working sets. The 70–75% range for 8–12 reps is a reliable starting point.
What percentage of 1RM should I train at for muscle growth?
65–80% of your 1RM for 6–12 reps is the hypertrophy range most supported by exercise science. This corresponds to the rows labelled "Hypertrophy" in the training percentage table above. The 70–75% range hits the highest volume of effective reps per set for most lifters.
Your 1RM is your baseline. Track every session against it.
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