Bench Press RM Conversion Calculator

By entering the weight, reps, and sets, the estimated 1RM will be calculated.

If there is a discrepancy between the calculated estimated 1RM and your current max, it may indicate that this rep range is a weakness.

You can choose to focus on strengthening the weight and rep range of this weakness over a certain period, and it can also help you assess progress in your next cycle.

1RM Conversion Calculator

Enter your bench press weight to calculate the estimated 1RM for each number of repetitions.

Bench Press RM Calculator [Weight × Reps × Sets]

Enter your bench press weight, reps, and sets to calculate your estimated 1RM.

Bench Press RM Conversion Table

The vertical axis represents the weight (kg), and the horizontal axis represents the number of repetitions.

 The point where your lifted weight and rep count intersect shows your estimated RM (Repetition Max).

Bench Press RM Calculation Method

How to Calculate 1RM

1RM = (Weight × Reps ÷ 40) + Weight

This is a commonly used formula to estimate one-repetition maximum (1RM).
It is a simplified version of the Brzycki formula, often used for practical RM estimation.

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Set Multiplier Coefficients

To account for multiple sets, the working weight is multiplied by a set coefficient to calculate the estimated 1RM.

(Note: These coefficients are based on current data and will be updated as more data becomes available. The current values are derived from the training records of over 500 users via the official “Utsu Bench” LINE account.)

[Set Count Coefficients]

Number of Sets	Multiplier
1 Set	1.00
2 Sets	1.02
3 Sets	1.03
4 Sets	1.04
5 Sets	1.05
6 Sets	1.06
7 Sets	1.07
8 Sets	1.08
9 Sets	1.09
10 Sets	1.10

Validity of the Formula and Coefficients

There are many ways to calculate RM estimates, but in practice, the difference in accuracy between formulas isn’t particularly significant.

What truly matters is consistency—using the same method each time to track progress and understand:

• How close your estimated 1RM is to your actual 1RM
  
• Whether you’re improving over time based on past RM estimates
  

For those interested in academically validated RM estimation methods, refer to the following research:

Brzycki Formula

Brzycki, M. (1993)
Title: Strength Testing — Predicting a One-Rep Max from Reps-to-Fatigue
Published in: Journal of Physical Education, Recreation & Dance
Citation: Brzycki, M. (1993). Strength testing—predicting a one-rep max from reps-to-fatigue. JOPERD, 64(1), 88–90.

Journal of Strength and Conditioning Research

LeSuer DA, McCormick JH, Mayhew JL, Wasserstein RL, Arnold MD. (1997).
The accuracy of prediction equations for estimating 1-RM performance in the bench press, squat, and deadlift.
Journal of Strength and Conditioning Research, 11(4), 211–213.

How to Use RM Estimation in Bench Press

Let’s consider the meaning of estimating your 1RM from your 10-rep max, 8-rep max, or 5-rep max in bench press training.

For example, if you input “80 kg × 10 reps × 1 set” into the calculator, it gives an estimated 1RM of 100 kg.

But does this value apply equally to everyone? The answer is no.

Rep Strength vs. 1RM Strength

Some individuals can lift 100 kg even with a 10-rep max of just 75 kg, while others may need 85 kg for 10 reps to reach the same estimated max.

This depends on whether you’re stronger in higher-rep sets or in single-rep maximal effort.

If this pattern shows consistently across different weight and rep ranges, it may indicate a personal tendency or trait.

Weakness Indicator

However, it’s not always enough to simply say “I’m stronger at reps” or “I’m better at singles.”

If there’s a significant gap between your estimated 1RM and your actual 1RM in a specific rep range, that may indicate a weakness in that range.

For instance, say your actual 1RM is 100 kg, and your training records show:

• 5-rep max: 90 kg → Estimated 1RM = 101 kg
  
• 10-rep max: 75 kg → Estimated 1RM = 93 kg
  

This suggests that your 5-rep strength aligns well with your 1RM, but your 10-rep strength is lagging behind.

This may simply be individual variation—but if your training has focused mostly on 5-rep sets, the lack of volume at higher reps might be holding you back.

Based on data from hundreds of personalized training programs, we’ve observed that athletes who focused too heavily on low-rep training often saw significant improvements in their 1RM after emphasizing 10-rep sets—even among those with 1RMs exceeding 200 kg.

How to Use the RM Calculator with the 10/8/5 Program

Let’s talk about how to use the RM calculator effectively when following a 10/8/5 program.

This program focuses on improving your 10-rep max, 8-rep max, and 5-rep max over time.

At the end of each training cycle, you record your best sets and calculate your estimated 1RM using the calculator.

Example:

If your current 1RM is 100 kg and your best sets during the first cycle were:

• 10-rep max set: 75 kg × 10 reps × 5 sets
  
• 8-rep max set: 80 kg × 8 reps × 5 sets
  
• 5-rep max set: 87.5 kg × 5 reps × 5 sets
  

Then your estimated RMs are:

• 75 kg × 10 reps × 5 sets = 98 kg
  
• 80 kg × 8 reps × 5 sets = 100 kg
  
• 87.5 kg × 5 reps × 5 sets = 103 kg
  

This means:

10-rep < 8-rep < 5-rep

To break past your current 1RM of 100 kg and reach 102.5 kg, you need to improve your 10-rep and 8-rep maxes.

If, after 3 to 6 months of training, this gap doesn’t close, you may benefit from focusing on a 10/8 program to strengthen those weaker rep ranges.

When a specific rep range becomes a limiting factor, this calculator can help identify it and guide your training focus for continued progress.