One Rep Max Calculator: Estimate 1RM for Bench, Squat, Deadlift

If you’ve ever finished a heavy set and wondered what you could have lifted for just one rep, this guide will show you how to estimate your one rep max using proven formulas. No all-out max needed—just a submaximal set and a quick calculation.

Epley formula: 1RM = weight × (1 + reps / 30) ·
Brzycki formula: 1RM = weight × (36 / (37 − reps)) ·
Example: 80 kg × 8 reps → Epley ~101.3 kg, Brzycki ~99.3 kg

What Is a One Rep Max Calculator?

A one rep max calculator uses submaximal lifting data — the weight you lifted and the number of reps you completed — to predict the maximum load you could handle for a single repetition. Instead of risking injury with a maximal effort, you input a set of 3–10 reps and get an estimated 1RM in seconds. These calculators are built on mathematical formulas that model the relationship between reps and fatigue, and they’re a staple in strength training apps and gym programming (StrengthJourneys – Brzycki Formula 1RM Calculator).

How does a 1RM calculator work?

Every calculator asks for two pieces of data: the weight used and the number of reps performed to failure (or within a few reps of failure). The formula then applies a rep‑weight coefficient derived from empirical studies. For example, the Epley formula multiplies the weight by (1 + reps / 30), which means each additional rep adds roughly 3.33% to the estimated max (Arvo.guru – 1RM Formulas Compared). The result is a number you can use to set training percentages.

Why is it important to know your one rep max?

• It lets you calculate exact percentages for periodized programs: 70% of 1RM for hypertrophy, 85% for strength.
• It reduces the need for frequent max testing, which wears down the central nervous system and increases injury risk (StrengthJourneys – Brzycki Formula 1RM Calculator).
• It provides a benchmark to track progress without having to hit a new max every month.

How Do I Calculate My One Rep Max?

To start, you need two numbers: the weight you lifted and the reps you completed to near failure. Use a weight that allows you to get between 3 and 10 reps. Then apply one of the formulas below.

1. Select a weight you can lift for 3–5 reps with good form.
2. Perform the set until you cannot complete another rep (or stop 1–2 reps shy of failure).
3. Record the weight and the number of reps.
4. Plug the numbers into your chosen formula (Epley or Brzycki).
5. Calculate the estimated 1RM and use it to set training percentages.

What data do I need to input?

You need only the weight (in kg or lb) and the exact number of reps performed. Most calculators also allow you to select the formula.

Which formula should I use: Epley, Brzycki, or Lombardi?

Epley and Brzycki are the most widely studied. Epley tends to be slightly more accurate in the 6–10 rep range, while Brzycki is often recommended for 1–6 reps. Lombardi is less common and less accurate for most lifters.

“The National Strength and Conditioning Association recommends submaximal testing for 1RM estimation to reduce injury risk.” – NSCA guidelines

How Accurate Is a One Rep Max Calculator?

Accuracy varies by formula and rep range. Most calculators estimate within ±5–10% of your actual max for sets of 1–10 reps. The error grows when using more than 10 reps or when the exercise differs from the original studies.

What margin of error should I expect?

Epley and Brzycki are both within ±5–7% for most trained lifters using moderate rep ranges. Lombardi’s error is higher, around ±8–10%.

Can I rely on it for programming my training?

Yes, as a starting point. Use the estimate to set percentages, but adjust based on actual performance. Retest after 4–6 weeks of consistent training.

“Jeff Nippard advocates using the Epley formula for most compound lifts due to its simplicity and acceptable accuracy.” – Jeff Nippard

What Is My One Rep Max for Bench Press, Squat, and Deadlift?

The same formulas apply across exercises, but typical 1RM values differ. Below are common ranges for intermediate lifters.

One rep max calculator bench press

Intermediate male: 185–225 lb; intermediate female: 100–125 lb.

One rep max calculator squat

Intermediate male: 225–315 lb; intermediate female: 135–185 lb.

One rep max calculator deadlift

Intermediate male: 275–405 lb; intermediate female: 185–245 lb.

The pattern: Lower-body lifts generally yield higher 1RMs due to larger muscle mass. Use the same formula but note that squat and deadlift estimates may be slightly less accurate because of technique and leverage differences.

How Do I Use a One Rep Max Calculator for Incline Bench and Pull Ups?

One rep max calculator incline bench

The same Epley/Brzycki formulas work, but incline bench 1RM is typically 10–15% lower than flat bench due to reduced shoulder involvement.

One rep max calculator pull up

For pull-ups, treat bodyweight as the “weight” and add extra weight if used. Then apply the formula with your total resistance.