Strength Calculator

Weight
Reps

Your One-Rep Max (one-rm): ?

95%: ?
90%: ?
85%: ?
80%: ?
75%: ?
70%: ?
65%: ?
60%: ?
55%: ?
50%: ?

Strength Calculator – Estimate 1RM & Training Weights

The Strength Calculator is a powerful tool for estimating your One-Rep Max (1RM), setting appropriate training weights, and measuring lifting progress. It’s especially useful for athletes, weightlifters, and anyone following a strength training program.

What is a Strength Calculator?

This tool estimates the maximum amount of weight you can lift for one repetition (1RM) based on the weight and number of reps you already perform. It also helps calculate percentages of 1RM to guide you in your workout plans.

How to Use the Strength Calculator

  1. Enter the weight lifted.
  2. Input the number of repetitions completed at that weight.
  3. Click "Calculate" to see your 1RM and training loads at various intensity levels.

Formula Used

Several formulas are available to estimate your 1RM. One commonly used is the Epley Formula:

1RM = Weight × (1 + Reps ÷ 30)

Training Percentage Chart (Based on 1RM)

% of 1RM Usage
50–60%Warm-up / Recovery
65–75%Hypertrophy Training
80–90%Strength Training
90–100%Max Strength / Testing

Benefits of Using a Strength Calculator

  • Track lifting progress over time
  • Design safe and effective training programs
  • Avoid overtraining or undertraining
  • Set realistic strength goals

Who Should Use This Tool?

  • Powerlifters and bodybuilders
  • CrossFit and HIIT athletes
  • Sports trainers and gym-goers
  • Physical therapists tracking strength recovery

Related Tools

FAQs about the Strength Calculator

1. What is 1RM in strength training?

1RM (One Rep Max) is the maximum weight you can lift for one complete repetition of an exercise.

2. How accurate is the 1RM estimate?

It gives a close approximation. Accuracy improves with correct form and a reasonable rep range (1–10).

3. Which formula does the calculator use?

By default, it uses the Epley formula, but some tools also offer Brzycki or Lander formulas.

4. Can I use this calculator for squats and deadlifts?

Yes, it works for any major compound lift like squats, deadlifts, bench presses, and overhead presses.

5. How often should I update my 1RM?

Every 4–8 weeks, or when you noticeably improve strength and lift heavier weights with the same rep range.