One-Rep Max (1RM) Calculator (Epley, Brzycki & Lombardi)

Compute 1RM plus 90%, 85%, 80%, 75%, and 70% training load percentages.

Estimated One-Rep Max (Epley 1RM)
116.67 kg
Brzycki 1RM 112.5 kg
Lombardi 1RM 117.46 kg
85% Working Load (≈5 reps) 99.17 kg
75% Hypertrophy Load (≈10 reps) 87.5 kg
Inputs
kg
Weight lifted for the set (kg or lb).
reps
Completed repetitions before failure (1 to 15 reps).
Results & Graph
Estimated One-Rep Max (Epley 1RM)
116.67 kg
Brzycki 1RM
112.5 kg
Lombardi 1RM
117.46 kg
85% Working Load (≈5 reps)
99.17 kg
75% Hypertrophy Load (≈10 reps)
87.5 kg

Estimated One-Rep Max (Epley 1RM)

Graph 1 • Lift Weight Kg Sensitivity Recalculates the domain equation across 50% to 150% of the primary input while holding other parameters constant.
0 kg 94.5 kg 189 kg 50%: 58.33 kg 58.3 50% 75%: 87.5 kg 87.5 75% 100%: 116.67 kg 116.7 100% 125%: 145.83 kg 145.8 125% 150%: 175 kg 175 150%
Graph 2 • Primary & Supporting Metric Comparison Compares the primary output alongside supporting domain benchmarks.
Estimated One-Rep Max (Epley 1RM) 116.67 kg Brzycki 1RM 112.5 kg Lombardi 1RM 117.46 kg 85% Working Load (≈5 reps) 99.17 kg
Graph 3 • Exact Output Table & Units Displays each calculated output in its exact domain unit.
Estimated One-Rep Max (Epley 1RM)116.67 kgBrzycki 1RM112.5 kgLombardi 1RM117.46 kg85% Working Load (≈5 reps)99.17 kg75% Hypertrophy Load (≈10 reps)87.5 kg
Summary: Lifting 100 kg for 5 reps projects an Epley 1RM of 116.7 kg and a Brzycki 1RM of 112.5 kg.
Summary: Lifting 100 kg for 5 reps projects an Epley 1RM of 116.7 kg and a Brzycki 1RM of 112.5 kg.

Formula & Mathematical Methodology: One-Rep Max Reference Equation

1RMEpley = liftWeight × (1 + reps / 30)
1RMBrzycki = liftWeight × (36 / (37 − reps))
1RM_Epley = liftWeight × (1 + reps / 30); 1RM_Brzycki = liftWeight × (36 / (37 − reps))
  • liftWeightKg: Lift Weight Kg (kg)
  • reps: Reps (reps)

Rounding: Intermediate calculations retain full IEEE-754 floating-point precision; displayed clinical and fitness metrics round to 1 or 2 decimal places.

Worked Example: Benchmark Scenario: One-Rep Max

Compute 1RM plus 90%, 85%, 80%, 75%, and 70% training load percentages.

  1. Enter your current anthropometric, laboratory, or training measurements in the units indicated.
  2. Substitute the values into the reference formula: 1RM_Epley = liftWeight × (1 + reps / 30); 1RM_Brzycki = liftWeight × (36 / (37 − reps)).
  3. Compare the primary output and supporting thresholds across all three custom SVG charts.
Result: Evaluates One-Rep Max using 1RM_Epley = liftWeight × (1 + reps / 30); 1RM_Brzycki = liftWeight × (36 / (37 − reps)).

Frequently Asked Questions

How is the One-Rep Max (1RM) Calculator (Epley, Brzycki & Lombardi) calculated?

It evaluates 1RM_Epley = liftWeight × (1 + reps / 30); 1RM_Brzycki = liftWeight × (36 / (37 − reps)) using your entered parameters and displays supporting clinical or training thresholds alongside three interactive SVG visualizations.

Can I compare multiple scenarios side by side?

Yes. Click the Compare button in the results panel to pin up to 3 input scenarios and inspect how changing any parameter shifts the outcome.

Are my health or fitness inputs stored on any server?

No. Every calculation executes 100% inside your browser tab so sensitive health and wellness numbers never leave your device.

Health & Fitness • Strength & Conditioning Guide

How to Use the One-Rep Max (1RM) Calculator (Epley, Brzycki & Lombardi): Practical Guide & Visual Analysis

Estimate One-Repetition Maximum (1RM) from submaximal weight and repetitions across Epley, Brzycki, and Lombardi formulas. Adjust the inputs above to view instant numerical outputs, three custom domain-specific SVG graphs, and reference methodology. Whether you are researching one-rep max (1rm) calculator (epley, brzycki & lombardi), one-rep max, one rep max, strength & conditioning calculator, this interactive tool helps you estimate One-Repetition Maximum (1RM) from submaximal weight and repetitions across Epley, Brzycki, and Lombardi formulas.

Interpreting the 3 Custom Visual Graphs & Key Outputs

As you adjust Lift Weight Kg, Reps, the calculator immediately computes Primary physiological or clinical metric, Supporting reference benchmarks, 3-Panel custom domain SVG visualization and updates all three domain-specific SVG charts in real time. Instead of relying on a single static figure, you can inspect the primary domain diagram, component breakdown, and multi-point trajectory curve to see how changing your inputs shifts the final result. Use the Compare (up to 3 scenarios) button to evaluate side-by-side variations before making a decision.

Real-World Benchmark & Planning Tips (Global Clinical & Exercise Physiology Reference)

In our benchmark scenario (Benchmark Scenario: One-Rep Max), Evaluates One-Rep Max using 1RM_Epley = liftWeight × (1 + reps / 30); 1RM_Brzycki = liftWeight × (36 / (37 − reps)). Keep in mind that uses peer-reviewed population equations and standard physiological constants. For related calculations in Health & Fitness, explore BMI Calculator (Body Mass Index), Calorie Needs & TDEE Calculator, Body Fat (US Navy), Lean Body Mass & Body Surface Area Calculator.