1RM Back Squat Calculator — Estimate Your Max (Epley Formula)
The back squat 1RM is the single most useful number a lifter can carry around — it sets the loading for every working set, picks meet attempts, and benchmarks whether your last training block actually moved the needle. This estimator runs your top set (weight × reps) through the Epley equation, 1RM = w × (1 + r/30), the same predictor used by Wendler's 5/3/1, Sheiko templates, and most coach spreadsheets. Two other equations get cited a lot: Brzycki (w × 36/(37 − r)), which trims a couple of pounds off Epley and tends to match true singles better at 6+ reps, and Lombardi (w × r^0.10), which overshoots once you push past 8. None of these care whether you squat high-bar Olympic style or low-bar powerlifting — but your numbers will. Low-bar usually moves 5–12% more weight than high-bar for a trained lifter, so plug in whichever stance you actually compete in. For reference points: ExRx and Stronger by Science strength standards put a novice male squat (200 lb bodyweight) around 230 lb, an intermediate lifter around 315 lb, advanced around 405 lb, and elite/competitive at 500 lb+. For women at 145 lb bodyweight, those bands run roughly 125 / 175 / 235 / 290 lb. Use the calculator to set your next training cycle without having to grind a true single under a bar that hates you.
To estimate your 1RM squat with the Epley formula: **1RM = Weight × (1 + Reps ÷ 30)**. Example: 100 kg × 5 reps → 100 × (1 + 5/30) = **116.7 kg**. Use 3–6 rep sets for best accuracy (±2–5% error).
When to use this calculator
- Picking USAPL or USPA meet attempts from training PRs — opener at 90–92% of your estimated 1RM (e.g., 405 lb predicted → 365 lb opener), second at 96–98% (390 lb), third at 100–103% (405–415 lb) so you don't bomb out on squat
- Setting your training max (TM) for Wendler 5/3/1 — Jim's rule is TM = 85–90% of estimated 1RM, so a 500 lb predicted squat runs the cycle off a 425–450 lb TM (Week 3 top set: 95% TM = 405–428 lb × 1+ AMRAP)
- Running a peak strength block at 85–95% 1RM (heavy doubles and singles in the 4 weeks before a meet) without a true max test eating recovery you don't have
- Programming a hypertrophy phase at 65–75% 1RM for 8–12 rep sets — e.g., 405 lb 1RM → 265–305 lb working sets for 4×10 quad-focused volume
- Sanity-checking a recent paused squat PR — if you grind out 315 × 5 paused, that's a ~365 lb paused 1RM; comparing it to your touch-and-go 1RM tells you how much your stretch reflex is buying you
- Tracking Bulgarian-method daily max work — re-estimating projected 1RM weekly from your daily top single + back-off rep work, so you can spot stagnation before it becomes overreaching
Worked Example
- You lifted 100 kg for 5 reps
- 1RM = 100 × (1 + 5/30) = 100 × 1.1667
- Estimated 1RM = 116.7 kg
How it works
4 min readThe Math — Epley, Brzycki, Lombardi Compared
All three formulas take the same two inputs (weight on the bar, reps completed at or near failure) and predict a 1-rep max. They disagree most at high reps:
Epley (1985): 1RM = w × (1 + r/30)
Brzycki (1993): 1RM = w × 36 / (37 − r)
Lombardi(1989): 1RM = w × r^0.10
O'Conner(1989): 1RM = w × (1 + 0.025r)Worked example — 100 kg × 5 reps:
Epley : 100 × (1 + 5/30) = 100 × 1.167 = 116.7 kg
Brzycki : 100 × 36/(37 − 5) = 100 × 1.125 = 112.5 kg
Lombardi: 100 × 5^0.10 = 100 × 1.175 = 117.5 kg
O'Conner: 100 × (1 + 0.125) = 100 × 1.125 = 112.5 kgThe spread (~5 kg) is normal. For 3–5 rep sets the formulas converge within 2–3%. Above 8 reps, Lombardi overshoots by 5–10% and Brzycki tends to be more accurate.
Common Squat Weights by Rep Count (100 kg 1RM)
Use this reference table if your 1RM is near 100 kg. Scale proportionally.
| Reps | Epley 1RM | % of 1RM | Training goal |
|---|---|---|---|
| 1 | 100 kg | 100% | Max single / competition |
| 2 | 106.7 kg | 95% | Peaking, heavy doubles |
| 3 | 110 kg | 92.5% | Strength triples |
| 5 | 116.7 kg | 85% | Strength 5/3/1 top set |
| 6 | 120 kg | 83% | Strength-hypertrophy crossover |
| 8 | 126.7 kg | 79% | Hypertrophy working sets |
| 10 | 133.3 kg | 75% | Volume hypertrophy |
| 12 | 140 kg | 71% | High-rep hypertrophy |
%1RM / Reps Reference Table
Useful for plugging into 5/3/1, Sheiko, Conjugate, or any percentage-based template:
| % of 1RM | RPE | Typical Reps | Use |
|---|---|---|---|
| 100% | RPE 10 — true max | 1 | Competition / test |
| 95% | RPE 9 | 2 | Peaking singles |
| 90% | RPE 8 | 3–4 | Heavy strength |
| 85% | RPE 7 | 5–6 | 5/3/1 top sets |
| 80% | RPE 6.5 | 6–8 | Strength-hypertrophy |
| 75% | RPE 6 | 8–10 | Volume / hypertrophy |
| 70% | RPE 5 | 10–12 | Hypertrophy block |
| 65% | RPE 4 | 12–15 | Endurance / warm-up |
Squat Strength Standards (back squat, kg, by training level)
| Level | 70 kg BW | 80 kg BW | 90 kg BW |
|---|---|---|---|
| Beginner | 60–80 kg | 70–95 kg | 80–105 kg |
| Novice | 80–100 kg | 95–115 kg | 105–130 kg |
| Intermediate | 100–130 kg | 115–145 kg | 130–165 kg |
| Advanced | 150–185 kg | 175–210 kg | 195–235 kg |
| Elite (competitive) | 200+ kg | 230+ kg | 260+ kg |
(Source: ExRx.net, Stronger by Science, StrengthLevel)
Bar Position Changes The Number
A high-bar (Olympic) squat and a low-bar (powerlifting) squat produce different 1RMs from the same athlete:
Depth Standards
| Standard | Definition | Where |
|---|---|---|
| Parallel | Top of knee level with hip crease | USAPL, USPA, IPF |
| Full depth (ATG) | Hip well below knee, hamstrings on calves | Olympic weightlifting, CrossFit |
| High squat | Hip above knee | Gym only — red-lighted in meets |
Programming Your 1RM Number
Wendler 5/3/1: runs every cycle off a Training Max (TM) = 85–90% of estimated 1RM. Week 3 top set is 95% TM × 1+ AMRAP. You re-estimate 1RM each cycle from that AMRAP.
Sheiko #29/#32: squat days run at 70–85% 1RM for sets of 2–5 reps. Total reps per session at >70% can exceed 30 — accurate 1RM matters a lot.
Bulgarian method: requires a daily heavy single. Back-off sets run at 85–90% of the day's top single.
Smolov base cycle: 4 squat sessions/week, percentages built off a fresh 1RM. Plug a stale or inflated 1RM into Smolov and you'll quit by Week 2.
Common Errors
1. AMRAP wasn't actually AMRAP. If you stop a top set with 2–3 reps in reserve, Epley underpredicts your max. Push the set to where the next rep would have failed.
2. No spotter or safeties. Set the safeties at the bottom of your squat, use a power rack. If neither is available, cap the test at 5RM and trust the math.
3. High-rep test sets. Epley is most accurate at 1–6 reps. Above 10 reps, the formula overshoots by 10–15%.
4. Comparing across gear/bar position. A belted, sleeved low-bar squat can be 10–20 kg above an unbelted high-bar single. Tag your inputs with the gear used.
5. Testing too close to a meet. Don't test a true 1RM in the last 14 days before competition. Use a 3RM or 5RM at 4–6 weeks out.
Frequently asked questions
What's the Epley formula for 1RM and how accurate is it?
Epley (1985): 1RM = Weight × (1 + Reps ÷ 30). At 3–6 reps the formula is typically within ±2–5% of a true max. Above 10 reps accuracy drops to ±10–15%. The Epley equation is used in virtually every strength program (5/3/1, Sheiko, Smolov) as the de facto standard for estimating 1RM from submaximal sets.
What's a strong back squat for a 200 lb man?
Going by ExRx and Symmetric Strength standards at 200 lb bodyweight: novice ~230 lb, intermediate ~315 lb, advanced ~405 lb, elite/competitive ~500 lb+. A 1.5× bodyweight squat (300 lb) is the common recreational lifter marker; 2× bodyweight (405 lb) is the threshold most competitive lifters aim to cross.
What's a strong squat for a woman at 145 lb bodyweight?
Strength standard bands: novice ~125 lb, intermediate ~175 lb, advanced ~235 lb, elite ~290 lb. A 2× bodyweight squat (290 lb) at 145 lb places a female lifter very competitively at USAPL 63–69 kg meets.
How often should I squat — once, twice, or more per week?
Depends on the program: Wendler 5/3/1 runs once a week heavy plus an optional lighter day. Texas Method uses 3× per week (volume Monday, light Wednesday, intensity Friday). Sheiko runs 2–3 squat sessions/week. For most intermediate lifters, 2 sessions/week (one heavy, one volume) hits the sweet spot without compromising recovery.
Why does my calculated 1RM feel too high when I actually try it?
Three usual culprits: (1) the test set wasn't true AMRAP — you left reps on the bar, so Epley overprojects; (2) you tried the 1RM cold or after fatigue; (3) bar position changed — you tested high-bar in training but tried a low-bar single. Recompute from a fresh 3RM, fully warm up (45–60 min), and match bar position.
What's the typical high-bar to low-bar squat ratio?
Most trained lifters move 5–12% more weight low-bar than high-bar. A 405 lb high-bar squat usually translates to about 425–455 lb low-bar once technique is dialed in. The gap is larger for taller lifters with long femurs.
Should I test a true 1RM or trust the calculator?
For 90% of lifters in 90% of training blocks: trust the calculator. A true 1RM eats 7–10 days of recovery, needs a 45–60 min warm-up, and carries real injury risk. Reserve direct 1RM testing for competition day or once every 8–12 weeks. Use 3RM or 5RM retests every 4 weeks — that's what 5/3/1 and Juggernaut are built around.
How long does it take to recover after a max squat test?
Plan on 5–10 days of reduced volume and intensity after a true 1RM squat. Days 1–3: mobility work, very light bike. Days 4–6: 50–65% bar work, no AMRAPs. Day 7+: ramp back to 75–85% working sets. Even elite lifters (Ed Coan, Kirk Karwoski training logs) show ~10 days of dialed-back volume after meet-day attempts.
Does the calculator work for paused squats and tempo squats?
The math is the same but the inputs aren't comparable. A 3-second paused squat at 100 kg × 5 reps doesn't predict the same 1RM as touch-and-go 100 kg × 5 reps — your paused 1RM is typically 5–8% lower than competition 1RM. Use paused-set data only when projecting paused competition attempts; mixing rep schemes contaminates the estimate.
What if I'm a beginner and don't know my top set?
Don't test a 1RM. Run Starting Strength or StrongLifts 5×5 for 12 weeks and let linear progression reveal your 5RM. Once you stall on linear progression (usually around bodyweight × 1.2–1.5 squat), plug the last successful 5×5 set into the calculator — that gives a reliable estimated 1RM to build the next program on.
Sources and references
- NSCA — Testing Maximum Strength (Essentials of Strength Training and Conditioning)
- USA Powerlifting (USAPL) — Technical Rules Book
- Stronger by Science — How Accurate Are Estimated 1RMs? (Greg Nuckols)
- ExRx.net — Strength Standards by bodyweight and training age
- Mayhew et al. (1992) / Reynolds et al. (2006) — Validation of 1RM prediction equations