A clean set of 100 kg for 5 reps is a fact under the bar. An estimated one-rep max (1RM) of “about 117 kg” from that set is a formula projection. Useful for programming percentages. Not identical to a spotter-backed single you grind today. This guide owns that distinction, a verified Epley vs Brzycki twin, and a %1RM intensity ladder for working loads. Open the One-Rep Max Calculator for the live estimate, formula delta, and ladder.
What this guide owns
- Submax performance versus estimated 1RM.
- Epley and Brzycki formulas, plus why they diverge.
- %1RM intensity ladder for programming loads.
- Safety notes and when not to chase weekly true maxes.
It is not a mortgage points break-even clock and not an escrow shortage twin.
Submax set vs estimated 1RM
Submax set = weight × reps you actually completed with acceptable form Estimated 1RM = formula(weight, reps)
Programs often prescribe “80% of 1RM.” That only works if the 1RM number is a consistent estimate. Weekly all-out singles are optional for most lifters; a hard set in roughly the 2–10 rep range is usually enough to refresh the estimate.
Very high-rep sets (for example 15+) make every popular formula less trustworthy. Prefer a challenging set closer to strength work.
Two common formulas (same set, two projections)
Epley
1RM ≈ weight × (1 + reps / 30)
Brzycki (for reps under 37)
1RM ≈ weight × (36 / (37 − reps))
Verified twin: 100 kg × 5
Epley ≈ 100 × (1 + 5/30) = 100 × 1.1667 ≈ 116.7 kg Brzycki ≈ 100 × (36 / 32) = 100 × 1.125 ≈ 112.5 kg Formula delta ≈ 4.2 kg
That delta is formula noise, not a second personal record. Pick one formula for a training block and stay consistent, or use the calculator’s selected formula while watching Epley and Brzycki side by side.
At higher reps the gap can widen. Example sketch on 100 kg × 15: Epley ≈ 150 kg, Brzycki ≈ 164 kg (about 14 kg apart). That is a reason to avoid estimating from marathon sets.
Lombardi and O’Conner appear on the tool as alternate sketches. They are not “more true”; they are different curves through the same idea.
Why %1RM ladders matter
Relative intensity scales across lifters better than absolute kilos alone. Once you have an estimated 1RM, common programming bands look like:
Using Epley ≈ 116.7 kg from the twin above:
| %1RM | Approx. load | Typical use (literacy) |
|---|---|---|
| 50% | 58 kg | Warm / speed |
| 60% | 70 kg | Technique |
| 70% | 82 kg | Volume |
| 75% | 88 kg | Hypertrophy-ish |
| 80% | 93 kg | Strength work |
| 85% | 99 kg | Heavy |
| 90% | 105 kg | Peak / singles |
| 95% | 111 kg | Near max |
Round to available plates. The ladder is a map, not a mandate. Fatigue, sleep, and exercise selection still move what you can do today.
The calculator also inverts an Epley-style relationship for rough loads at 2, 3, 5, 8, and 10 reps. Treat those as planning targets, not guarantees.
How to run a clean estimate
- Warm up thoroughly on the same lift.
- Hit a hard set in about 2–10 reps with form you would accept in training.
- Enter weight, reps, and a formula on the One-Rep Max Calculator.
- Read estimated 1RM and the Epley/Brzycki delta.
- Pull working weights from the intensity ladder.
- Recheck the estimate when progress stalls or every few weeks, not every session with a true max.
Pair protein and energy tools when recovery and intake matter: Protein Intake, Calorie Calculator. Session energy cost is a different job on Calories Burned.
Safety and when not to test a true 1RM
- No reliable spotter or safety arms for the lift.
- Pain, acute injury, or form that collapses near failure.
- Beginners still learning the pattern.
- High fatigue weeks where ego maxes steal recovery from productive training.
Estimated 1RMs exist so you can train hard without turning every Tuesday into a meet. If you do test a true max, treat it as a rare event with a plan, not a weekly identity check.
Common failure modes
- Treating a formula output as a competition total.
- Estimating from sloppy high-rep sets.
- Switching formulas every week and “progressing” on noise.
- Programming 90% singles from an inflated estimate.
- Ignoring that bench, squat, and deadlift estimates are lift-specific.
FAQ
Is a submax set the same as my 1RM?
No. The set is what you lifted. The 1RM number is a projection used for percentages.
Which formula should I use?
Epley is a common default. Brzycki is widely used and can diverge as reps change. Stay consistent inside a block; prefer about 2–10 reps.
What is the intensity ladder?
Working loads at common percentages of your estimated 1RM (about 50–95%) for programming.
Should I test a true 1RM every week?
Usually no. True maxes need warm-ups, spotters, and recovery. Many programs prefer periodic submax estimates.
Is this medical or coaching advice?
No. Educational only. Calculators do not replace spotters or qualified coaching.
Bottom line
Estimate 1RM from a quality submax set, treat Epley/Brzycki disagreement as noise, and program from the %1RM ladder. Run the twin and ladder on the One-Rep Max Calculator, and keep true max attempts rare, spotted, and optional.