How We Estimate Your Deadlift 1RM
The Deadlift 1RM Calculator uses the Epley equation as its default estimate.
Epley is a widely used general-purpose 1RM equation and works particularly well as a practical estimate when the input comes from a relatively heavy, low-repetition set. Because there is no single repetition-based equation that has been shown to be universally best for every deadlifter, we use Epley as a straightforward default and allow you to compare it with other formulas.
Deadlift repetition performance can be unusually sensitive to how the set is performed. A set of reset repetitions, where the bar becomes stationary on the floor between reps, may represent a different strength demand from touch-and-go repetitions that make greater use of the preceding eccentric phase. For the most useful estimate, enter a set performed using the same deadlift style and repetition standard you normally use.
Why Might I Choose a Different Deadlift Formula?
Brzycki may be useful if the Epley estimate consistently feels too aggressive or if you prefer a more conservative number for programming.
Lander can provide another useful comparison, particularly when using moderate-repetition sets.
If you have previously performed both a repetition max and a true deadlift 1RM, compare the formulas against your own performance. Individual lifters can have very different repetition endurance, so your personal training history can eventually become more informative than population averages.
Which 1RM Formula Is Best for Me?
The best equation for an individual lifter is the one that most consistently reflects their actual performance.
If you know both a recent true 1RM and a recent repetition-max set, compare each formula against that result. For example, if your actual squat max is 405 lb and Lander repeatedly predicts about 400–410 lb while Epley predicts 425 lb, Lander may be the more useful formula for your squat.
This does not necessarily mean that equation is more accurate for your bench press or deadlift. Your repetition strength can differ between movements.
Rep Range and Consistent Tracking
For the most useful estimate, use a challenging set of approximately 2 to 8 repetitions. As rep counts increase, differences in muscular endurance become more important and the predictions from different formulas tend to spread farther apart.
Formula selection matters less when reps are low because common equations tend to produce more similar estimates near the low-repetition end.
When using estimated 1RM to track progress, consistency is often more important than chasing the formula that produces the highest or lowest number. Compare sets performed with similar technique and rep ranges using the same equation.
Research comparing 1RM prediction equations suggests accuracy can vary by exercise, rep range, and population. Your own repetition strength may fit another equation more closely.
Method and Limitations
All formulas use completed reps plus entered RIR as estimated repetition capacity. Technique differences, fatigue, exercise selection, and individual repetition endurance can affect the result. The formula range is a comparison, not a statistical confidence interval.
These estimates are educational, not medical advice or a substitute for direct testing by a qualified professional. Prediction error and individual variation are expected.