One Rep Max Calculator
Bench Press — estimated 1-rep max
154lb
Bench
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Squat
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Deadlift
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OHP
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Rep-max chart
Estimated weight for 1–12 reps at your current max.
Training percentages
Common %1RM targets for programming warm-up and working sets.
The Free One Rep Max Calculator Built for Real Training
A one rep max calculator estimates the single heaviest weight you could lift for one complete repetition of an exercise — your 1RM — without you having to actually attempt that lift. Instead of loading a bar to failure and risking a missed rep under near-maximal load, you enter the weight and reps from a normal working set, and the calculator applies a proven mathematical formula to project what you could lift for just one rep. It's the fastest, safest way to know your current strength level and program future training around real numbers instead of guesswork.
This one rep max calculator goes further than a single output. Along with your estimated max, you get a full rep-max chart showing projected weights for 1 through 12+ reps, and a percentage-based training chart breaking your max down into the loads you'd actually use for warm-ups, working sets, and top singles — all generated instantly, on one page, with no reload.
How This Calculator Works: Epley vs. Brzycki
Two formulas power the estimate, and you can toggle between them above to compare results side by side.
The Epley formula — 1RM = weight × (1 + reps ÷ 30) — is one of the most widely used 1RM formulas in strength training. It scales in a straightforward, near-linear way as rep count increases, which makes it a reliable default for compound barbell lifts like bench press, squat, deadlift, and overhead press.
The Brzycki formula — 1RM = weight × 36 ÷ (37 − reps) — takes a different mathematical approach and is generally considered slightly more conservative, particularly in the 1–10 rep range. Many coaches consider it marginally more accurate for lower-rep sets, though it becomes unstable and unreliable much above 10 reps.
Neither formula is "correct" in every situation — they're statistical models built from data on how lifters' strength typically holds up across rep ranges. The real key to an accurate estimate isn't which formula you pick, it's keeping your test set low-rep (ideally 5 reps or fewer) and close to genuine effort.
One Rep Max Calculator for Bench Press
Bench press is the most commonly tested lift on this tool, and for good reason — it's the standard benchmark most lifters use to track upper-body pressing strength. Select the Bench tab, enter the weight and reps from a recent working set, and you'll get an instant bench press one rep max estimate, plus the full rep-max and percentage charts scaled specifically to that number. Because grip and shoulder stability can limit rep count on bench press independent of raw pressing strength, use a set where your form stayed tight through every rep for the most reliable read.
One Rep Max Calculator for Squat
Squat strength tends to hold up differently across rep ranges than bench press — most lifters can grind out more reps at a given percentage of their squat max than they can on bench. Select the Squat tab and enter your numbers to get a squat one rep max estimate built from the same Epley/Brzycki math, so you can compare your squat and bench numbers side by side using the lift comparison chips above the chart.
Deadlift and overhead press work exactly the same way — pick the tab, enter your set, and get a labeled, comparable result for that lift specifically. Because the calculator remembers your results across lifts as you switch tabs, you end up with a complete strength snapshot — bench, squat, deadlift, and overhead press — from one page, in under a minute.
Beyond a Single Number: Rep-Max Chart & Training Percentages
Most one rep max calculators stop at a single number. This one treats that number as the start of the useful part.
The rep-max chart converts your estimated 1RM into projected weights for every rep count from 1 to 12+, so you know exactly what to load for a heavy triple, an AMRAP set, or a 10-rep hypertrophy block — not just your theoretical single.
The training percentage chart does the same for percentage-based programming, breaking your max down from 100% to 50% in 5% increments, each labeled with how it's typically used (heavy singles, top sets, volume work, warm-ups). If your program calls for "5×5 at 80%," you don't need a separate calculator — the number is already sitting on the page.
How We Compare to a Typical Strength Level One Rep Max Calculator
Most strength level one rep max calculator tools — and most 1RM calculators in general — give you one formula, one number, and stop there. You still have to do the percentage math yourself, and if you train more than one lift, you're often re-entering numbers on a separate page or tool for each one.
This calculator is built to remove those extra steps: formula comparison, unit conversion, a full rep-max breakdown, percentage-based training numbers, and multi-lift comparison, all on a single page that updates instantly as you type — no reloads, no separate calculators for bench vs. squat vs. deadlift.
Who This Tool Is For
Whether you're a beginner trying to understand what "80% of your max" actually means in pounds or kilos, an intermediate lifter programming your next strength block, or a coach who needs quick, labeled numbers across several lifts and athletes, this one rep max calculator is built to get you from a working set to a full training picture in seconds — accurately, safely, and without any math of your own.
Frequently asked questions
How do I calculate my one rep max?
Enter the weight you lifted and the number of reps you completed for a single set into the calculator above. It applies the Epley or Brzycki formula to estimate the maximum weight you could lift for one repetition. For the most reliable estimate, use a set of 1–8 reps taken close to failure with good form.
How accurate is a one rep max calculator?
A one rep max calculator is highly accurate for sets of 1–5 reps, typically within a few percent of an actual tested max. Accuracy decreases as rep count increases, since formulas extrapolate from muscular-endurance data that varies between lifters. Treat the result as a strong training estimate rather than a guaranteed number.
What is the Epley formula?
The Epley formula estimates one rep max as 1RM = weight × (1 + reps ÷ 30). Developed by Boyd Epley, it's one of the most widely used 1RM formulas and tends to give slightly higher estimates at higher rep counts, making it a common default for compound lifts like bench press, squat, and deadlift.
What is the Brzycki formula?
The Brzycki formula estimates one rep max as 1RM = weight × 36 ÷ (37 − reps). Developed by strength coach Matt Brzycki, it's generally considered more conservative than Epley and is often regarded as more accurate in the 1–10 rep range, though it becomes unstable above roughly 10 reps.
Which one rep max formula is most accurate?
Neither formula is universally more accurate — each performs best in a different rep range. Brzycki tends to track closer to real-world results between 1–10 reps, while Epley stays more stable at higher rep counts. The biggest factor in accuracy is testing with a low rep count (5 reps or fewer); formula choice matters far less than that.
How do I calculate my bench press one rep max?
Use the Bench tab in the calculator above, enter the weight you benched and the reps you completed, and your estimated bench press one rep max appears instantly, along with a full rep-max chart and percentage-based training numbers scaled to that lift.
How do I calculate my squat one rep max?
Select the Squat tab, enter the weight and reps from your working set, and the calculator estimates your squat one rep max using the Epley or Brzycki formula. Because squat allows more muscular endurance than bench press for most lifters, use a recent, honest-effort set for the most reliable number.
How do I calculate my deadlift one rep max?
Choose the Deadlift tab and enter your working weight and rep count. Deadlift 1RM estimates can run slightly high for lifters with strong pulling endurance, since deadlift typically allows more reps at a given percentage of max than bench press — factor that in when programming from the estimate.
What percentage of my one rep max should I train with?
It depends on your goal: 85–100% for maximal strength and low-rep singles or doubles, 70–85% for classic strength-building sets of 3–6 reps, and 50–70% for hypertrophy, volume, or warm-up work. The percentage training chart above converts your estimated 1RM into ready-to-load numbers across that full range.
How often should I test my one rep max?
Every 4–8 weeks for lifters following a structured program, or at the end of a training block. Testing more frequently adds fatigue and injury risk without much added benefit — recalculating from a recent hard set of 3–5 reps is usually enough to track progress between true max tests.
Is it safe to test my actual one rep max?
True 1RM testing carries real injury risk, especially without a spotter, a proper warm-up, or solid technique. Most lifters — beginners and intermediates especially — get equal or better information from a submaximal set (3–5 reps) run through a one rep max calculator, with far less strain on the joints and nervous system.
Can I estimate my one rep max without lifting heavy?
Yes. A one rep max calculator is built for exactly this — enter a moderate, submaximal set (ideally 3–8 reps at a hard but controlled effort) and the formula extrapolates your estimated max without you needing to attempt a true single.
What rep range gives the most accurate one rep max estimate?
Sets of 1–5 reps give the most accurate estimates, since both Epley and Brzycki are extrapolating a shorter distance from the actual tested point. Estimates from sets above 10 reps become progressively less reliable and should be treated as rough approximations only.
Why do different formulas give different results?
Each formula — Epley, Brzycki, and others — was derived from a different research population and models the reps-to-load relationship slightly differently. The differences are usually small at low rep counts and grow larger as reps increase, which is why comparing both formulas, as this calculator does, gives you a realistic range rather than a single potentially misleading number.
How do I use my one rep max to plan a training program?
Once you have an estimated 1RM, use the percentage training chart to assign loads: heavy singles or doubles near 90–95% for peaking, working sets at 70–85% for strength blocks, and lighter volume work at 50–65% for hypertrophy or deload weeks. Recalculate every few weeks as your strength improves so your percentages stay accurate.
What is a good one rep max for my bodyweight?
'Good' is relative to bodyweight, training age, and sex — common reference points treat roughly bodyweight for bench, 1.5x bodyweight for squat, and 2x bodyweight for deadlift as solid intermediate benchmarks. These vary by source, so use them as rough context rather than a strict target.
Does grip strength affect one rep max accuracy?
For deadlift, and to a lesser extent bench press, yes — if your grip fails before your prime movers do, your rep count (and therefore your estimated 1RM) reflects grip endurance rather than true strength. Using straps for the submaximal test set can produce a more accurate estimate of your raw pulling or pressing max.