Formula Used
The calculator first finds the load used for calculation. Displayed mode uses entered load, optional sled weight, and machine multiplier. Effective mode also multiplies by sine of the sled angle.
Calculation load: entered load plus included sled weight, multiplied by machine ratio. For effective mode, multiply that value by sin(angle).
Epley: 1RM = load × (1 + reps ÷ 30). Brzycki: 1RM = load × 36 ÷ (37 − reps). Lombardi: 1RM = load × reps^0.10.
O'Conner: 1RM = load × (1 + 0.025 × reps). Mayhew: 1RM = 100 × load ÷ (52.2 + 41.9e-0.055×reps). Wathan: 1RM = 100 × load ÷ (48.8 + 53.8e-0.075×reps).
How to Use This Calculator
Enter the load you pressed for a clean set. Add completed reps and any reps in reserve. Choose the unit, formula, and load mode. Add sled weight if you want the tool to include it.
Use sled angle when effective load matters. Use machine multiplier for lever, cable, or selectorized machines. Enter body weight if you want a strength ratio. Press calculate, then review the result above the form.
Use CSV for spreadsheet tracking. Use PDF for a simple training record. Repeat the test with similar depth, stance, and tempo for better progress comparisons.
Leg Press Strength Planning
A leg press one rep max is an estimate of the heaviest load you may press for one complete repetition. It is useful when a true maximal attempt is not practical. Many lifters use it to set training loads, compare blocks, and watch progress without testing to failure each week. The calculator uses your best recent set, then applies common strength equations. It can also include sled weight, machine angle, and a machine multiplier.
Why This Estimate Matters
Leg press machines vary a lot. Some use a forty five degree sled. Some are horizontal. Others use cables, levers, or selector stacks. Because of that, the number on one machine may not equal another machine. This tool lets you decide whether to use the displayed load or an effective vertical load. That makes notes clearer when training across different gyms.
Using Results Wisely
The result should guide training, not replace judgment. A strong set with controlled depth is more useful than a loose set with short range. For best estimates, use a set of three to ten reps. Higher reps can still work, but fatigue and endurance affect the answer more. Enter reps in reserve when you stop before failure. The calculator then treats the set as if those extra reps were possible. Record seat setting, foot stance, and sled type beside each result. These details improve repeatability.
Programming With The Number
After you estimate your max, choose a training max percentage. Many lifters use eighty five to ninety five percent of the estimated max for planning. Then daily work sets may be based on that safer number. The target reps field also helps you find a planned load for a future set. Round the load to match available plates or machine jumps. Compare sessions only when depth and tempo stay similar.
Important Safety Notes
Warm up first. Keep your hips, back, and knees controlled. Do not lock the knees hard. Stop if pain appears. A calculator cannot judge form, injury risk, or medical limits. Use a spotter, trainer, or clinician when needed. Treat unusual results as prompts to review your inputs. Retest with a steady set before changing your whole program. Always progress with steady patience.
FAQs
What is a leg press one rep max?
It is an estimated maximum load you could press once with good form. The estimate comes from a submaximal set and a selected strength formula.
Which formula should I choose?
The average option is useful for general planning. Epley and Brzycki are common choices for lower rep sets. Compare formulas when you want a range.
Should I include sled weight?
Include sled weight when you know it and want a full machine load. Leave it out when your gym already lists the total moving load.
What does effective vertical load mean?
It adjusts the moving load by sled angle. A forty five degree sled has less vertical resistance than a straight vertical press.
Are high rep sets accurate?
They can be useful, but accuracy often drops as reps rise. Sets from three to ten reps usually give better strength estimates.
What is reps in reserve?
Reps in reserve means how many more clean reps you think you could have done. The calculator adds it to completed reps.
Can I compare different leg press machines?
You can compare them, but note the machine type, angle, sled weight, and seat setting. Different designs can change the real resistance.
Is this a medical or coaching tool?
No. It is a planning aid. It cannot judge injury risk, form quality, pain, or personal training readiness.