Mr Calcu | Unlock your true strength potential with our 1RM calculator—train smarter, lift heavier, and hit your goals faster.

Discover your one rep max instantly. Boost gains and prevent injury with science-backed methods. Maximize your strength and training success today.

Max Strength One Rep Max Calculator

One Rep Max Calculator Guidelines

You're just a few steps away from smarter training:

Enter the exact weight lifted (W) and reps completed (R) for a recent set.
Ensure both values are positive and reps are ideally between 1 and 10.
Compare estimates from different formulas to find a balanced 1RM prediction.
Use calculated 1RM to determine working weights for strength, hypertrophy, or power phases.
Update your 1RM monthly or bi-monthly to reflect progress.

One Rep Max Calculator Description

What is One Rep Max (1RM)?

Your One Rep Max (1RM) is the highest amount of weight you can lift for a single, complete repetition of a given exercise. It's essential for designing strength training programs and assessing progress.

Why Estimate 1RM?

Determine appropriate weights for hypertrophy, strength, or power-focused training.
Track performance over time and adjust workout intensity.
Avoid injury risk by estimating rather than attempting a maximal lift.

Common Estimation Formulas

These formulas predict your 1RM based on submaximal reps and weight lifted:

Epley Formula:
1RM = W × (1 + R/30)

Brzycki Formula:
1RM = W × (36 / (37 − R))

Lombardi Formula:
1RM = W × R^0.10

Where:
W = weight lifted (kg or lbs)
R = repetitions (1–10 recommended)

Edge Case Considerations

R = 1: Outputs are nearly identical to the input weight (true max lift).
R ≥ 12: Results lose precision due to endurance factors.
W = 0 or R = 0: Invalid input; no meaningful result.
High reps (R > 15): Output underestimates actual strength.
Heavy loads, low reps (e.g., W > 250kg, R = 2): Formulas diverge slightly; interpret with caution.

Pro Tip: For best results, use a rep range between 3–8 reps. It balances exertion and accuracy without over-fatiguing your muscles.

Real-World Applications

Case Study 1 – Competitive Powerlifting

Lifter: Emily, 63kg powerlifter
Test: 150kg deadlift × 3 reps
Formula: Epley → 1RM = 150 × (1 + 3/30) = 165kg
Result: Plan attempts for meet day: 150 / 160 / 170kg

Case Study 2 – Hypertrophy Training

Lifter: Jason, intermediate athlete
Test: 70kg bench press × 12 reps
Formula: Brzycki → 1RM = 70 × (36 / 25) = 100.8kg
Result: Adjust training cycle to hit 70–80% of this new estimated max

Advanced Usage

Plan training blocks using percentages of 1RM (e.g., 75%, 85%).
Compare estimates from all formulas to understand your strength profile.
Retest periodically to reflect adaptations and gains.

Take control of your training—calculate your 1RM now and turn effort into real results.

Example Calculation

Formula	Expression	Example Calculation
Epley	W × (1 + R / 30)	100 kg × (1 + 5 / 30) = 116.67 kg
Brzycki	W × (36 / (37 − R))	100 kg × (36 / 32) = 112.50 kg
Lombardi	W × R^0.10	100 kg × 5^0.10 ≈ 116.23 kg
Edge Case: R = 1	Epley → W × (1 + 1 / 30)	100 kg × 1.0333 = 103.33 kg
Edge Case: R = 15	Brzycki → W × (36 / 22)	100 kg × 1.636 = 163.6 kg

Parameter	Unit
Weight Lifted (W)	kg or lbs
Repetitions (R)	reps (ideally 1–10)

Frequently Asked Questions

It is the maximum weight you can lift for one complete repetition, indicating your overall strength level.

The calculator uses the Epley, Brzycki, and Lombardi formulas to provide reliable 1RM estimates based on your input.

Your 1RM helps set training intensities and monitor progress, guiding adjustments in your strength training regimen.

Not entirely. Most 1RM formulas are optimized for rep ranges between 1 and 10. Endurance plays a larger role in higher reps, which skews results.

Yes, but you must estimate the effective resistance. For example, during push-ups, you lift approximately 65–70% of your body weight.

Each formula models strength differently—some favor low-rep loads, others better handle higher-rep inputs. Use multiple for comparison.

Be cautious using formula outputs for high-rep sets. Consider performing a lower-rep test or adjust the estimated value downward for safety.

Estimations are generally accurate within 5–10% when reps are between 3 and 10 and effort is maximal.

Mr Calcu | Unlock your true strength potential with our 1RM calculator—train smarter, lift heavier, and hit your goals faster.

Max Strength One Rep Max Calculator

One Rep Max Calculator Guidelines

You're just a few steps away from smarter training:

One Rep Max Calculator Description

What is One Rep Max (1RM)?

Why Estimate 1RM?

Common Estimation Formulas

Edge Case Considerations

Real-World Applications

Case Study 1 – Competitive Powerlifting

Case Study 2 – Hypertrophy Training

Advanced Usage

Example Calculation

Frequently Asked Questions

What is a one rep max (1RM)?

Which formulas are used in this calculator?

How can I use the 1RM value?

Are the results accurate for high-repetition sets (e.g., 15+ reps)?

Can I use this calculator for bodyweight exercises?

Why do different formulas give different 1RM results?

What should I do if my reps exceed 12?

How accurate is 1RM estimation from reps?

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