One Rep Max for 275 lbs x 8 reps
Estimated one-rep max (1RM) for 275 lbs x 8 reps, using the Epley, Brzycki, and Lombardi formulas, plus a full percent-of-1RM training table. Adjust the inputs below for your own numbers.
Estimated One-Rep Max
343 lbs
Average of Epley, Brzycki, and Lombardi formulas
| Formula | Published | Estimated 1RM |
|---|---|---|
| Epley | 1985 | 348.3 lbs |
| Brzycki | 1993 | 341.4 lbs |
| Lombardi | 1989 | 338.6 lbs |
Lifting 275 lbs for 8 reps corresponds to an estimated one-rep max of about 343 lbs (average of the Epley, Brzycki, and Lombardi formulas), meaning you likely could not lift much more than 343 lbs for a single all-out repetition today.
What is a One Rep Max Calculator?
A one rep max (1RM) calculator estimates the maximum weight you could lift for a single complete repetition of an exercise while maintaining proper form, based on a lighter set you actually performed for multiple reps. Rather than requiring you to attempt a true maximal single lift — which carries real injury risk without a spotter or coach — these formulas extrapolate from a safer, sub-maximal set to a reasonably accurate estimate.
1RM is the standard reference point strength athletes and coaches use to design training programs, track progress over time, and set measurable, comparable strength goals across different lifters and body weights.
Training Weight by Percent of 1RM
Based on your estimated 343 lbs one-rep max, here is the training weight for every major percentage of 1RM, along with the rep range and training goal each percentage is typically used for.
| % of 1RM | Weight | Typical Reps | Training Goal |
|---|---|---|---|
| 100% | 342.8 lbs | ~1 | Max Strength |
| 95% | 325.7 lbs | ~2 | Max Strength |
| 90% | 308.5 lbs | ~4 | Strength / Power |
| 85% | 291.4 lbs | ~6 | Strength |
| 80% (closest to your set) | 274.2 lbs | ~8 | Strength |
| 75% | 257.1 lbs | ~10 | Hypertrophy (Muscle Growth) |
| 70% | 240.0 lbs | ~12 | Hypertrophy (Muscle Growth) |
| 65% | 222.8 lbs | ~15 | Muscular Endurance |
| 60% | 205.7 lbs | ~18 | Muscular Endurance |
| 50% | 171.4 lbs | ~24 | Endurance |
The Three 1RM Formulas
Epley and Brzycki are the two most widely cited 1RM formulas, and they produce identical results at exactly 10 reps by design — Epley tends to estimate slightly higher at low rep counts and Brzycki slightly higher above 10 reps. Lombardi's formula uses a different mathematical shape (a power curve rather than a straight line) and tends to sit closest to the other two in the middle of the rep range. This calculator averages all three so no single formula's quirks dominate the result.
Why Formulas Diverge at Higher Rep Counts
Every 1RM formula is a mathematical approximation fit to data from sets of roughly 1-10 reps. Above about 10-12 reps, fatigue, technique breakdown, and metabolic factors start to matter more than raw strength, so the relationship between reps and true 1RM becomes far less consistent from person to person. That's why this calculator (and most 1RM calculators) treats estimates from very high rep sets — 15, 20, or more reps — as noticeably less reliable than estimates from a 3-8 rep set.
Training Zones Explained
Different percentages of 1RM are associated with different training adaptations. Loads near 85-100% of 1RM, performed for 1-6 reps, primarily build maximal strength and neural efficiency. Loads around 70-80% for 7-12 reps are the classic hypertrophy (muscle growth) range, balancing enough mechanical tension with enough total volume. Lighter loads below 65% for 15+ reps mainly build muscular endurance. None of these zones are strict boundaries — most well-rounded programs cycle through several rep ranges over a training block rather than living in just one.
Why Not Just Test a True 1RM?
Directly testing a maximal single lift is the most accurate way to know your 1RM, but it also carries the highest injury risk, requires a spotter or safety setup for most barbell lifts, and demands a level of technical proficiency and neural readiness that a fatigued or untrained lifter may not have on a given day. Estimating 1RM from a safer, sub-maximal set — ideally taken close to failure at 3-8 reps — gives a similarly useful number for programming purposes without the added risk of a true maximal attempt.
Example — Your Current Inputs
Lifting 275 lbs for 8 reps corresponds to an estimated one-rep max of about 343 lbs (average of the Epley, Brzycki, and Lombardi formulas), meaning you likely could not lift much more than 343 lbs for a single all-out repetition today.
Additional Example — 185 lbs x 8 Reps
A lifter who bench presses 185 lbs for 8 reps gets an Epley estimate of about 234 lbs, a Brzycki estimate of about 230 lbs, and a Lombardi estimate of about 227 lbs — averaging to roughly 230 lbs estimated 1RM. From there, 85% of 1RM (about 196 lbs) would be a typical heavy strength-focused working weight for 5-6 reps, while 70% (about 161 lbs) suits higher-volume hypertrophy sets of 10-12 reps.
About These Parameters
- Weight Lifted
- The load you actually lifted for the set you're using as the basis of the estimate — typically the bar plus plates, not including bodyweight for bodyweight-assisted movements. For the most accurate estimate, use a set taken close to failure (you could not have done many more reps with good form), since formulas assume the set represents close to your true effort ceiling at that rep count.
- Repetitions
- How many reps you completed with that weight in a single set. Lower rep counts (3-8) generally produce more reliable 1RM estimates than very high rep counts, since the mathematical relationship between reps and strength holds more consistently in that range. A 1-rep entry simply returns your lifted weight as the estimate, since no extrapolation is needed.
- Units
- Whether your weight is entered in pounds or kilograms. The formulas themselves are unit-agnostic — the same equations apply regardless of unit, so switching units simply relabels the result rather than changing how it's calculated.
Frequently Asked Questions
Which 1RM formula is the most accurate?
No single formula is universally "correct" — each was derived from a different research population and each tends to be slightly more or less accurate depending on the lift, the lifter's training background, and the rep range used. Epley and Brzycki are the two most commonly cited in strength and conditioning literature, and averaging all three (as this calculator does) tends to smooth out any one formula's individual bias.
How many reps should I use to get the most accurate estimate?
Somewhere between 3 and 8 reps, taken close to muscular failure, generally produces the most reliable estimate. Below 3 reps there's little data for the formula to extrapolate from, and above about 10-12 reps, fatigue and endurance factors increasingly distort the strength-to-reps relationship the formulas assume.
Is it safe to attempt my estimated 1RM in the gym?
Treat the estimate as a training guide, not a target to immediately attempt. If you do want to test a true 1RM, work up gradually in small increments with a spotter or safety bars, and stop well short of your estimate on any day you don't feel fully recovered — true maximal attempts carry meaningfully more injury risk than submaximal training sets.
Does my 1RM estimate change between exercises?
Yes — run this calculator separately for each lift (bench press, squat, deadlift, etc.), since your strength-to-fatigue relationship differs by movement pattern, the muscle groups involved, and your technical proficiency with that specific lift. A rep count that gives a reliable estimate on squat won't necessarily be equally reliable on an isolation exercise like a bicep curl.