About
A weight training calculator hub for lifters
GymCalc is a free tool that brings together the calculations lifters look up most often. Work out your 1RM (one-rep max), plate combinations, protein intake, and carb/protein/fat macros directly in your browser — no install or sign-up required.
The 1RM calculator estimates your one-rep max from the weight and reps you lifted using several formulas — Epley, Brzycki, Lombardi, and more — then averages them and provides a table of set weights and expected reps at intensities from 100% down to 50%. The plate calculator shows a visual plate combination for each side of the bar once you enter your target weight and bar weight.
The protein calculator uses evidence-based g/kg ranges tied to your body weight and goal (maintain, build muscle, cut) to calculate your daily recommended protein, along with meal distribution and food equivalents. The nutrition calculator uses the Mifflin-St Jeor formula to determine your basal metabolic rate and total daily energy expenditure (TDEE), then derives your target calories and carb/protein/fat grams.
Every calculation uses standard sports science formulas and runs entirely on your device. None of the values you enter — body weight, age, or anything else — is ever sent to or stored on a server. Results are for reference only and don't replace medical or nutritional advice.
Good to Know
What is 1RM (one-rep max)?
It's the maximum weight you can lift for a single repetition. Because attempting an actual one-rep max carries a high risk of injury, it's common practice to estimate it with a formula based on a set of several reps at a lighter weight.
Why show several formulas at once?
Formulas like Epley, Brzycki, and Lombardi each behave slightly differently depending on rep count. Rather than relying on just one, averaging several estimates gives you a more stable benchmark.
How much protein should I eat?
A general guideline is 1.2–2.2g per kg of body weight per day. Higher ranges are used when building muscle or cutting, to help preserve muscle mass. The calculator shows the range and recommended value for your goal.
How are TDEE and macros determined?
First, the Mifflin-St Jeor formula is used to calculate basal metabolic rate (BMR), which is then multiplied by an activity factor to get TDEE (total daily calories burned). Calories are then adjusted for your goal (cut, maintain, bulk), protein and fat are set first, and the remaining calories are filled in with carbohydrates.
Frequently Asked Questions
How accurate is the 1RM calculation?
It's most accurate for 1–10 reps, and the margin of error grows as rep count increases. GymCalc averages several formulas to provide a more stable estimate than any single formula. Keep in mind it's only an estimate — adjust your actual training weight to how you're feeling on the day.
Is the body weight or age I enter sent to a server?
No. All calculations run entirely in your browser's JavaScript, and no value is ever sent to or stored on a server.
What plates does the plate calculator use?
In kg mode it uses standard plates of 25, 20, 15, 10, 5, 2.5, and 1.25 kg; in lb mode it uses 45, 35, 25, 10, 5, and 2.5 lb. If your target weight can't be matched exactly, it shows the closest combination and the remaining weight.
Can women use the strength standards as-is?
The strength standards (bodyweight multiples) in the Lift Directory are approximate figures based on men. For women, adjust by roughly 0.6–0.7× for upper-body lifts and 0.7–0.8× for lower-body lifts.
Can I follow the results exactly?
Results are reference values based on standard formulas. If you have an injury, a medical condition, or specific weight-management needs, consult a doctor, dietitian, or trainer before applying them.