Lander Formula: 1RM Calculator and Complete Guide
The Lander formula estimates 1RM as 100 × weight / (101.3 − 2.67123 × reps). It is the most conservative of the seven major formulas and is well-suited to injury-prevention programming and older athletes.
Strength Training Researcher
Published · Last reviewed · 6 min read
Lander formula calculator
Single-formula calculator. For an averaged estimate across all 7 formulas, use the main calculator.
History and origin
Jeffrey E. Lander published his 1RM prediction equation in the National Strength and Conditioning Association Journal in 1985: 1RM = 100 × weight / (101.3 − 2.67123 × reps). The formula uses a hyperbolic structure that produces consistently lower estimates than other major formulas, making it the most conservative of the seven. Lander's calibration emphasized safety for return-to-training and older athletes; the lower estimate reduces the risk of overshoot when programming percentages from a calculated 1RM. Because of its conservative bias, Lander is rarely the highest 1RM number across the formula set — it's typically the lowest or second-lowest.
Lander, J. (1985). Maximums based on reps. National Strength and Conditioning Association Journal, 6(6), 60-61.
When to use the Lander formula
Best for
Injury prevention, older athletes, return-to-training
Limitation
Significantly underestimates for explosive and elite athletes
Compared to other formulas
Compared to Epley and Brzycki, Lander produces 1RM estimates 5-8% lower across all rep ranges. Compared to O'Conner (also conservative), Lander is similar at low reps but drops off slightly more aggressively at high reps. Lander's value is as a "lower bound" reference — if your trimmed-mean across all formulas is 320 lb and Lander says 305 lb, the safer programming starting point is closer to Lander's number.
How to use the Lander formula (step by step)
- Perform a heavy submaximal set. Perform a clean set of 2-10 reps to near-failure (RPE 8-9) on the lift you want to test. Record the weight and the rep count.
- Apply the Lander equation.
1RM = 100 × weight / (101.3 − 2.67123 × reps) - Read the estimated 1RM. The output is your estimated 1RM. For programming, multiply by 0.9 to derive your Training Max — this absorbs daily strength variability and reduces overshoot risk.
- Cross-check against other formulas. Run the same numbers through every other formula and compare. The main calculator does this automatically using a trimmed mean.
Worked examples — Lander formula
Computed with the Lander formula. Compare these single-formula estimates against the trimmed-mean average from our main calculator.
| Set | Weight × Reps | Lander 1RM (lb) |
|---|---|---|
| Example 1 | 135 lb × 10 | 181 lb |
| Example 2 | 185 lb × 8 | 231 lb |
| Example 3 | 225 lb × 5 | 256 lb |
| Example 4 | 315 lb × 3 | 338 lb |
| Example 5 | 405 lb × 1 | 411 lb |
How Lander compares to the other six formulas
The same submaximal set — 225 lb × 5 reps — produces different 1RM estimates depending on which formula you use. Here are all seven, side by side:
| Formula | Estimated 1RM | vs Lander |
|---|---|---|
| Epley | 263 lb | +7 lb |
| Brzycki | 253 lb | -3 lb |
| Lombardi | 264 lb | +8 lb |
| O'Conner | 253 lb | -3 lb |
| Mayhew | 268 lb | +12 lb |
| Wathan | 262 lb | +6 lb |
| Landerthis page | 256 lb | — |
See the full formula comparison page for accuracy data and decision-making guidance.
Lander reverse lookup: target 1RMs at common rep ranges
Working backward from a target 1RM, here's the working weight you would need to lift for various rep counts to predict that max via the Lander formula. Use this to set training targets for blocks aimed at hitting a specific number.
| Target 1RM | 3 reps | 5 reps | 8 reps | 10 reps |
|---|---|---|---|---|
| 200 lb | 187 lb | 176 lb | 160 lb | 149 lb |
| 300 lb | 280 lb | 264 lb | 240 lb | 224 lb |
| 400 lb | 373 lb | 352 lb | 320 lb | 298 lb |
| 500 lb | 466 lb | 440 lb | 400 lb | 373 lb |
Round to the nearest 5 lb when programming. For competition-style peaking, see the 5/3/1 calculator or RPE programming.
Validation research
The Lander formula has been evaluated in multiple peer-reviewed studies of 1RM prediction accuracy. Selected findings:
Mayhew, Wathan, and Brzycki produced the smallest error across bench, squat, and deadlift. Most formulas underestimated 1RM as reps increased.
LeSuer, D.A., McCormick, J.H., Mayhew, J.L., Wasserstein, R.L., & Arnold, M.D. (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.
Standard error of estimate ranged from 5.6 to 7.9 kg across formulas; high reps (>10) reduced accuracy meaningfully.
Reynolds, J.M., Gordon, T.J., & Robergs, R.A. (2006). Prediction of one repetition maximum strength from multiple repetition maximum testing and anthropometry. Journal of Strength and Conditioning Research, 20(3), 584-592.
In older adults, most formulas overestimated 1RM by 5-15%; conservative choices (Lander, O'Conner) outperformed.
Wood, T.M., Maddalozzo, G.F., & Harter, R.A. (2002). Accuracy of seven equations for predicting 1-RM performance of apparently healthy, sedentary older adults. Measurement in Physical Education and Exercise Science, 6(2), 67-94.
Lander Formula FAQ
Further reading & authoritative sources
These external sources informed the content on this page. Authoritative references are a hallmark of trustworthy strength training information; we link directly so you can verify and explore further.
- Wikipedia: One-repetition maximum
General reference for the 1RM concept and major prediction formulas.
- Essentials of Strength Training and Conditioning (NSCA, Human Kinetics)
The CSCS textbook chapter on load assignment includes the formulas covered here.
- LeSuer et al. (1997) — Accuracy of 1RM prediction equations
Foundational comparative study of 1RM prediction equation accuracy.
- Stronger by Science — Greg Nuckols, evidence-based training research
Greg Nuckols’ evidence-based commentary on rep-to-1RM relationships.
- OpenPowerlifting — global meet results database
Real-world meet results database for sanity-checking calculator output.
References
- Original publication: Lander, J. (1985). Maximums based on reps. National Strength and Conditioning Association Journal, 6(6), 60-61.
- LeSuer et al. (1997): LeSuer, D.A., McCormick, J.H., Mayhew, J.L., Wasserstein, R.L., & Arnold, M.D. (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.
- Reynolds et al. (2006): Reynolds, J.M., Gordon, T.J., & Robergs, R.A. (2006). Prediction of one repetition maximum strength from multiple repetition maximum testing and anthropometry. Journal of Strength and Conditioning Research, 20(3), 584-592.
- Wood et al. (2002): Wood, T.M., Maddalozzo, G.F., & Harter, R.A. (2002). Accuracy of seven equations for predicting 1-RM performance of apparently healthy, sedentary older adults. Measurement in Physical Education and Exercise Science, 6(2), 67-94.
- Wikipedia: One-repetition maximum — general reference for 1RM prediction equations.
- Essentials of Strength Training and Conditioning (NSCA, Human Kinetics) — NSCA CSCS textbook chapter on load assignment.