One Rep Max Calculator
Estimate your one-rep maximum using 7 research-validated formulas, then get your complete training load table, warm-up sets, and plate loading breakdown
Enter the weight you lifted for the reps below
Best accuracy at 1–10 reps. Avoid using sets above 15 reps.
Enter Weight and Reps to Calculate
Enter the weight you lifted and how many reps you completed above. Results appear automatically.
How to Use the One Rep Max Calculator
Enter Your Weight and Reps
Type the weight you lifted (in lbs or kg) and the number of complete repetitions you performed. For the most accurate result, use a weight you can lift between 2 and 5 times with full effort and proper form. Avoid using sets where you could have done many more reps — those numbers will overestimate your 1RM. The accuracy warning at the top of the results will flag if your rep count is above 10.
Choose a Formula or Use the Average
By default the calculator shows the average of all 7 research-validated formulas, which is the most robust general-purpose estimate. If you want to see results from a specific formula — for example, Brzycki for bench press or Epley for squat — select it from the Formula dropdown. The Formula Comparison chart below the main result always shows all 7 estimates side by side so you can see the full range of estimates at a glance.
Use the Training Load Table for Programming
Scroll down to the Training Load Table to find the exact weights you should be using for different training intensities. Find your goal — Maximal Strength (90–100%), Strength (80–90%), Hypertrophy (67–77%), or Endurance (50–67%) — and use the corresponding weight in your program. The warm-up set calculator below the table automatically generates a 7-step progressive warm-up ladder to your target weight.
Load the Bar with the Plate Calculator
Use the Plate Loading Calculator at the bottom of the results to find out exactly which plates to put on each side of the barbell for any target weight. The calculator automatically subtracts the standard 45 lb (20 kg) bar weight and shows you the optimal plate combination per side using standard plates. This eliminates the mental math of figuring out plate combinations during warm-up sets.
Frequently Asked Questions
What is the most accurate 1RM formula?
No single formula is universally the most accurate for all people and all exercises. Research suggests the Brzycki formula performs best for bench press and squat in the 3–8 rep range, while the Epley formula is a good general-purpose choice across most exercises at 2–10 reps. The Mayhew formula has strong NCAA validation for moderate rep ranges. For higher rep ranges (10–15), the Lombardi formula tends to be more accurate. The most reliable approach for most people is to use the average of all seven formulas, which smooths out the individual biases of each equation. Individual variation in muscle fiber composition and strength qualities also means one formula may simply fit your physiology better than others.
How many reps should I use for the best estimate?
The ideal rep range for accurate 1RM estimation is 2–5 reps. At 2–5 reps, the load is high enough that the repetition count strongly reflects your maximum strength capacity, and all seven formulas have a typical error margin of only 2–5%. As you move into the 6–10 rep range, the error grows to approximately 5–10% because high-rep performance increasingly reflects muscular endurance in addition to maximal strength. Above 12 reps, estimation accuracy drops substantially — the formulas were not designed to work reliably at those rep counts. If you are trying to get a precise number, choose a weight you can lift 3–5 times with maximal effort, rest fully, and then plug in those numbers.
Should I test my actual 1RM or use a calculator?
For most recreational lifters, using a calculator to estimate 1RM from a submaximal set is safer, more practical, and nearly as accurate as direct testing. Actual 1RM testing requires extensive warm-up (often 45–60 minutes), an experienced spotter, perfect technique, and significant recovery time — typically 3–5 days before hard training resumes. Direct testing is most appropriate for competitive powerlifters preparing for meets, athletes who need verified strength numbers for research, or advanced trainees who have regular coaching supervision. For general fitness and programming purposes, estimating from a set of 3–5 reps is excellent practice. Re-estimate every 4–6 weeks to keep your training percentages current.
How often should I recalculate my 1RM?
A common recommendation is to re-estimate your 1RM at the end of each training block, typically every 4–8 weeks. This is important because your true 1RM changes as you get stronger, and basing all your training percentages on an outdated number will make your sessions either too easy or too hard. Most periodized strength programs build in a test week or AMRAP (as many reps as possible) set at the end of a block specifically to update 1RM estimates. Some programs, like 5/3/1, use a conservative training max and add a fixed increment (e.g., 5 lbs for upper body, 10 lbs for lower body) each cycle rather than re-testing, which effectively adjusts the training max upward over time.
Why do different formulas give different results?
Each formula was derived from a different research study using a different sample of subjects, different exercises, and different statistical methods. The Epley and O'Conner formulas are linear — they assume a constant rate of strength decline per additional rep. The Mayhew and Wathen formulas use exponential functions, meaning the strength drop-off accelerates at higher rep counts. The Lombardi formula uses a power function. These different mathematical structures produce similar estimates at 2–5 reps but diverge increasingly as rep counts rise. Additionally, each formula was validated on a specific population (NCAA athletes, recreational lifters, older adults) and may not generalize equally well to all lifters. Using the average of all seven is the simplest way to account for these differences.
Is 1RM the same for all exercises?
No — your 1RM is specific to each exercise. A lifter with a 300 lb squat 1RM might have a 225 lb bench press 1RM and a 400 lb deadlift 1RM. The relationship between body weight and 1RM also differs by exercise: the deadlift typically allows the highest absolute loads because it engages the most total muscle mass, while the overhead press typically has the lowest 1RM of the major barbell lifts. Strength-to-bodyweight ratios reflect these differences — the standard for an intermediate male bench press is about 1.0× bodyweight, while the intermediate deadlift standard is about 1.5× bodyweight. You should calculate and track your 1RM separately for each major lift you train.