Brzycki 1rm Calculator
Our weightlifting calculator computes brzycki 1rm instantly. Get accurate stats with historical comparisons and benchmarks.
Formula
1RM = Weight / (1.0278 - 0.0278 x Reps)
The Brzycki formula estimates your one-rep maximum by dividing the weight lifted by a factor that decreases as reps increase. This creates an inverse relationship between load and repetitions, accurate for 1-10 rep ranges.
Worked Examples
Example 1: Intermediate Lifter 1RM Estimation
Problem: A lifter completes 185 lbs for 5 reps on bench press. Calculate their estimated 1RM using the Brzycki formula.
Solution: Brzycki Formula: 1RM = Weight / (1.0278 - 0.0278 x Reps)\n1RM = 185 / (1.0278 - 0.0278 x 5)\n1RM = 185 / (1.0278 - 0.139)\n1RM = 185 / 0.8888\n1RM = 208.2 lbs\nTraining Max (90%) = 208.2 x 0.9 = 187.4 lbs
Result: Estimated 1RM: 208.2 lbs | Training Max: 187.4 lbs
Example 2: Advanced Lifter Multi-Formula Comparison
Problem: A lifter completes 275 lbs for 3 reps on squat. Compare 1RM estimates across multiple formulas.
Solution: Brzycki: 275 / (1.0278 - 0.0278 x 3) = 275 / 0.9444 = 291.2 lbs\nEpley: 275 x (1 + 3/30) = 275 x 1.1 = 302.5 lbs\nLander: (100 x 275) / (101.3 - 2.67123 x 3) = 27500 / 93.29 = 294.8 lbs\nAverage of 3 formulas = 296.2 lbs
Result: Brzycki: 291.2 lbs | Epley: 302.5 lbs | Lander: 294.8 lbs | Average: 296.2 lbs
Frequently Asked Questions
What is the Brzycki formula and how does it estimate one-rep max?
The Brzycki formula was developed by Matt Brzycki in 1993 and is one of the most widely used equations for estimating one-rep max (1RM) from submaximal efforts. The formula is: 1RM = Weight / (1.0278 - 0.0278 x Reps). It works by establishing a mathematical relationship between the weight lifted and the number of repetitions performed to failure. The formula is most accurate when used with rep counts between 1 and 10, as higher rep ranges tend to introduce more variables like muscular endurance and cardiovascular fitness. Many strength coaches consider the Brzycki formula the gold standard for 1RM estimation because it closely matches actual maximal test results in clinical studies.
How accurate is the Brzycki 1RM formula compared to actual testing?
Research studies have shown that the Brzycki formula is accurate within 2-5% of actual 1RM values when performed with 1-10 repetitions. The formula tends to be most precise at lower rep counts (3-6 reps), where the estimate is typically within 1-3% of the true 1RM. At higher rep ranges (10+), accuracy decreases because factors like muscular endurance, cardiovascular fitness, and mental fatigue play larger roles in determining when failure occurs. Individual variation also affects accuracy since some lifters are naturally better at higher reps while others excel at low-rep maximal efforts. For the most reliable estimate, perform a set of 3-5 reps to true muscular failure with strict form.
How does the Brzycki formula differ from the Epley formula?
The Brzycki and Epley formulas use different mathematical approaches to estimate 1RM. The Brzycki formula (1RM = Weight / (1.0278 - 0.0278 x Reps)) produces a linear relationship between reps and load, while the Epley formula (1RM = Weight x (1 + Reps / 30)) uses a simpler linear equation. At low rep ranges (1-6), both formulas produce very similar results, typically within 1-2% of each other. The divergence increases at higher rep counts, where the Brzycki formula tends to give slightly lower estimates compared to Epley. Most strength coaches recommend comparing multiple formulas and using the average for the most reliable estimate. Neither formula is definitively superior across all situations and populations.
Can I use the Brzycki formula for all exercises?
While the Brzycki formula can be applied to any resistance exercise, its accuracy varies across different movements. It works best for compound barbell exercises like bench press, squat, deadlift, and overhead press, which were the exercises used in the original research. The formula is less accurate for isolation exercises (bicep curls, leg extensions) because these movements involve smaller muscle groups where fatigue patterns differ. Machine exercises may also produce less accurate estimates due to variable resistance profiles. For Olympic lifts (clean, snatch), the formula should not be used because these movements are highly technical and failure is determined by technique breakdown rather than muscular failure. Always test your actual 1RM periodically to validate the estimates.
What formula does Brzycki 1rm Calculator use?
The formula used is described in the Formula section on this page. It is based on widely accepted standards in the relevant field. If you need a specific reference or citation, the References section provides links to authoritative sources.
Can I share or bookmark my calculation?
You can bookmark the calculator page in your browser. Many calculators also display a shareable result summary you can copy. The page URL stays the same so returning to it will bring you back to the same tool.