Free strength tool
Estimate your one-rep max from a clean set of 1–10 reps, compare three common formulas and turn the result into practical training weights.
Put your estimate in context
Compare your estimated bench, squat or deadlift with MFO's bodyweight-based benchmarks.
The calculator runs your weight and reps through three established prediction equations: Epley, Brzycki and Lombardi. It displays every result, the full range and the middle estimate. That makes the disagreement between formulas visible instead of hiding it behind one authoritative-looking number.
w × (1 + r ÷ 30)
w × 36 ÷ (37 − r)
w × r^0.10
In the equations, w is the weight lifted and r is the number of completed reps. Kilograms and pounds work the same way because each equation returns the unit you enter.
It is an estimate, not a direct strength test. Accuracy usually improves when the input comes from a low-rep set performed close to your limit with consistent technique. The exercise, your training experience and the formula can all change the result, which is why this calculator shows a range.
No formula wins for every lift or lifter. This tool compares Epley, Brzycki and Lombardi, then uses the middle of the three estimates as its headline number so one unusually high or low result does not dominate.
Prediction becomes less dependable as reps rise. Research on submaximal testing generally supports using lower-repetition sets, so the tool stops at 10 rather than turning a high-rep endurance set into a false-precision max.
You do not need to. A hard but controlled multi-rep set is often enough for programming and progress tracking. If you choose to test a true maximum, use sound technique, suitable rack safeties and an experienced spotter where the lift requires one.
The 10-rep limit and accuracy cautions reflect validation research on submaximal 1RM prediction and research finding better prediction from lower-repetition sets, including 5RM testing and a recommendation not to exceed 10 reps. A systematic review of direct 1RM testing also found it generally reliable but noted that testing risks and familiarisation still matter.
This calculator provides a general estimate for education and training planning. It is not medical advice, coaching or a guarantee that a load is safe for you. Stop if you feel pain, and seek guidance from a qualified professional if you are new to lifting, returning from injury or unsure about your technique.
