1RM
The calculator stays the main job of the homepage.
1RM calculator
Estimate your one-rep max from a hard set and use it like a coach would.
This calculator averages Epley, Brzycki, and Lombardi so you can turn one solid work set into a practical loading number instead of guessing from feel alone.
- Best used with a technically clean, hard set in a lower or moderate rep range.
- Outputs both a formula average and a more conservative training max.
- Links into guides that explain when the estimate is useful and when it gets shaky.
3
Average three common equations instead of pretending one always wins.
Practical
Built for lifters, coaches, and normal gym users who just want a usable number.
Calculator
Use a recent hard set, not a random warm-up.
The cleaner the input, the better the estimate. For most people, a hard set of 3 to 6 reps gives a more useful planning number than a high-rep burnout set.
How the calculator works
It takes the weight and reps from one hard set, runs three common prediction formulas, and shows the average alongside a more conservative training max.
What the formulas are doing
Epley, Brzycki, and Lombardi each estimate how your rep performance scales to a single. None is perfect, so the average is usually more useful than acting like one equation is gospel.
How to use the result
Use it to set percentage-based work, sanity-check top-set loading, or track progress from repeated sets over time. If the estimate is going to drive your week, a training max is often the safer base.
Epley
Simple and widely used. Often feels sensible for everyday gym sets in lower or moderate rep ranges.
Brzycki
Usually reads a bit more conservatively as reps rise, which can be useful if your rep-out sets tend to inflate confidence.
Lombardi
Falls off less sharply at higher reps. Helpful as a comparison, but not a license to trust long rep sets without caution.
1. Use a real working set
The calculator works best when the input came from a genuine top set, not from a comfortable warm-up.
2. Keep the lift consistent
Track the same variation over time so the estimate means something. Different squat styles are different data.
3. Watch the trend
The exact number matters less than whether the estimate moves in the right direction across similar sessions.
Related guides
Start with these five practical reads.
If you want the calculator result to be more useful, these are the pages that explain how to interpret it without overcomplicating training.
Research overview
What current research says about 1RM prediction formulas
A practical summary of what the literature supports and where the method gets uncertain.
Formula comparison
Epley vs Brzycki vs Lombardi
See when each formula is more useful and why none of them deserves blind loyalty.
Testing strategy
Estimated 1RM vs true 1RM
Pick the right option for the job instead of turning testing into an identity issue.
Programming
How to use percentage-based training
Use structure without letting fixed numbers override the reality of the session.
Accuracy
Why high-rep sets can be less accurate
See why a set of 12 tells a different story than a hard set of 4 or 5.