Choose an exercise
Select Bench Press, Squat, Deadlift, Overhead Press, or Other so your result keeps the right training context.
STRENGTH TRAINING TOOL
1RM Calculator
Estimate your one-rep max from a recent weight-and-reps set, compare common formulas, and plan training percentages in pounds or kilograms.
- Epley + Brzycki estimates
- kg and lb support
- Instant browser calculation
- No account or upload
02
Example loaded
ESTIMATE
Estimated 1RM
262.5
lb
Epley estimate
Bench Press · 225 lb × 5 reps
Epley estimate · primary result
One-rep input used directly as the estimated 1RM.
Brzycki estimate
253.1 lb
Formula difference
9.4 lb
Training percentages
View full table below
50%
131.3 lb
70%
183.8 lb
80%
210.0 lb
90%
236.3 lb
95%
249.4 lb
Estimates are most useful with controlled sets of 2–10 reps. Technique, fatigue, range of motion, and equipment can change the result.
Estimated only; not a guaranteed true max. Warm up and use appropriate spotting or supervision for heavy lifting.
Example loaded
This is an estimated 1RM calculator for training reference. It does not guarantee that you can safely complete the displayed weight.
A SIMPLE THREE-STEP FLOW
How to use this 1RM calculator
A one rep max calculator works best when you start with a recent, controlled set that represents your current training. The tool turns that set into an estimate without requiring a true max test.
Enter weight and reps
Add the weight you completed and the number of full repetitions. Choose pounds or kilograms beside the weight field.
Calculate your estimate
Press Calculate 1RM to see the Epley estimate, a Brzycki comparison, and the difference between the formulas.
Review percentages
Use the percentage table as a planning reference, then adjust for your program, technique, recovery, and coaching.
THE BASICS
What is a one-rep max?
A one-rep max, usually written as 1RM, is the heaviest load a person can lift once with a defined technique standard. A tested 1RM is a real performance result. An estimated 1RM predicts that result from a submaximal set, such as 225 lb for 5 reps.
This 1RM calculator is useful when you want a repeatable training reference without performing a maximal attempt. Because the estimate comes from a formula, it should guide decisions rather than replace your judgment or a properly supervised test.
TRANSPARENT MATH
How this 1RM calculator works
The calculator uses the same weight and reps to show two common prediction equations. Epley is the primary result because it is simple to explain; Brzycki remains visible as a comparison so you can see why different calculators may disagree.
PRIMARY
Epley formula
estimated 1RM = weight × (1 + reps ÷ 30)
For 225 lb and 5 reps, Epley gives 262.5 lb. When reps equal 1, the calculator uses the input weight directly.
COMPARISON
Brzycki formula
estimated 1RM = weight × 36 ÷ (37 − reps)
For the same 225 lb set, Brzycki gives about 253.1 lb. The difference is a reminder that neither equation is a guaranteed max.
These equations are prediction methods for submaximal sets, not a substitute for a controlled strength test. Read the research abstract on PubMed.
PLAN THE NEXT SET
Training percentages from your estimated 1RM
Percentages turn an estimated max into practical reference points. The values below start with the live Epley result, so changing the weight, reps, unit, or rounding setting updates the table without changing the underlying exercise context.
| 1RM percentage | Reference weight | Relative load |
|---|---|---|
| 50% | 131.3 lb | |
| 60% | 157.5 lb | |
| 70% | 183.8 lb | |
| 75% | 196.9 lb | |
| 80% | 210.0 lb | |
| 85% | 223.1 lb | |
| 90% | 236.3 lb | |
| 95% | 249.4 lb |
Percentages are not fixed prescriptions. Choose a load that matches your program, readiness, technique, and the goal of the set.
COMMON USE CASES
Bench press, squat, deadlift, and more
You can use the same 1 rep calculator for most barbell or machine movements when the set has a clear weight and rep count. The exercise label organizes the result; it does not change the equation.
1RM Calculator for Bench Press
Use the 1RM Calculator for a completed bench press set to estimate a bench press max, compare the result with training percentages, and keep the estimate separate from a tested competition lift.
1RM Calculator for Squat
Use the 1RM Calculator for a consistent squat set with the same depth and equipment you normally use. Changes in stance, shoes, or depth can affect performance.
1RM Calculator for Deadlift
Use the 1RM Calculator for a recent deadlift set to plan submaximal work, but grip, setup, pause time, and fatigue may change the prediction.
1RM Calculator for Overhead Press
Use the 1RM Calculator for an overhead press or another lift when you have a clear weight and rep count. Keep the rep range controlled and treat the output as a reference for technical movements.
INTERPRET THE NUMBER
How accurate is an estimated 1RM?
An estimated 1RM can be useful for comparing training sessions and choosing a starting load, but its accuracy varies from person to person. The closer a set is to a controlled heavy effort, the more informative it may be; high-repetition sets often introduce more fatigue and technique drift.
Do not compare estimates as if they were lab measurements. Compare sets performed with similar standards, then use the result alongside how the lift felt, your recovery, and the actual performance of the next session.
Technique standard
Range of motion, tempo, pauses, and depth influence the weight a set represents.
Fatigue and readiness
Sleep, stress, nutrition, warm-up quality, and the previous session can shift performance.
Equipment and setup
Bars, machines, belts, shoes, surfaces, and lifting conditions are not interchangeable.
Repetition quality
A clean completed rep is more useful than a partial or assisted repetition.
INPUT BOUNDARIES
Use sensible inputs for a useful estimate
The calculator keeps the main path short, but it still checks the boundaries that can create misleading results or browser input errors.
| Input | What happens |
|---|---|
| Weight above 0 | Accepted up to 10,000 lb or kg. |
| Reps from 1 to 10 | Calculated with Epley and Brzycki. |
| Exactly 1 rep | The input weight is used directly. |
| Blank, zero, or negative weight | Inline error asks for a positive weight. |
| Blank, decimal, or 0 reps | Inline error asks for a whole number from 1 to 10. |
| More than 10 reps | Blocked because prediction confidence usually falls as reps rise. |
TRAIN RESPONSIBLY
Use 1RM estimates as a planning aid
A calculator can show a number quickly, but it cannot see your technique, pain, balance, fatigue, training history, or surroundings. Keep the word estimated in mind whenever you use the result to choose a load.
Warm up progressively, use a controlled range of motion, and ask a qualified coach or training partner for appropriate supervision when a lift is heavy or unfamiliar. Stop if a movement causes pain or feels unsafe.
Keep the original context
Use similar exercise standards when comparing estimates.
Round for real equipment
Choose a practical plate increment instead of chasing a decimal.
Do not force the result
An estimated max is not a target you must attempt today.
Protect your data
This page calculates locally and does not need your training history.
COMMON QUESTIONS
1RM calculator FAQ
Quick answers about one-rep max estimates, formulas, exercises, units, and repetition ranges.
What is a 1RM?
A 1RM is the heaviest weight you can lift once with a defined technique standard. This page estimates it from a completed submaximal set rather than asking you to test a true maximum.
How do I calculate my one-rep max?
Enter a completed weight and rep count, then choose Calculate 1RM. The tool applies the Epley formula and shows a Brzycki comparison plus training percentages.
What formula does this 1RM calculator use?
The primary result uses Epley: weight × (1 + reps ÷ 30). Brzycki is shown as an optional comparison because common formulas can produce different estimates.
Is Epley or Brzycki more accurate?
Neither formula is guaranteed to be more accurate for every lifter or exercise. Use the comparison to understand the range, then judge it against consistent training data.
Can I use this as a bench press max calculator?
Yes. Select Bench Press, enter a recent bench set, and use the estimate for training reference. The exercise label adds context but does not change the formula.
Can I calculate squat and deadlift 1RM?
Yes. Squat and Deadlift are included, and the same input flow can estimate an overhead press or another lift when you know the weight and reps.
Can I use kilograms and pounds?
Yes. Choose kg or lb beside the Weight field. Switching units converts the displayed weight and recalculates the estimate and percentage table.
How many reps should I enter?
Enter a whole number from 1 to 10. Lower-repetition, controlled sets generally make a more useful estimate than a long set performed under heavy fatigue.
READY TO CHECK A SET?
Estimate your next training reference
Use a recent completed set, calculate your estimated 1RM, and review the percentages before choosing your next working weight.