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Lifting Tool

Lifting Calculator

Convert pounds and kilos, load the bar with the right plates, and estimate your one-rep max — the three numbers you actually reach for in the gym.

These are the practical, in-the-gym calculations: unit conversion, barbell loading, and a one-rep-max estimate with a training percentage table. They're pure mechanics — no body-fat, calorie or body-image figures, which need a qualified professional behind them. Everything runs in your browser; nothing you type is sent anywhere.

Weight Converter

Pounds · Kilograms · Stone

Convert plate weights, dumbbell sizes or bodyweight between units.

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Barbell Plate Loader

Which plates go on the bar?

Enter your target total weight and the bar — it works out the plates to load on each side.

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One-Rep Max

Estimate your 1RM

Enter a weight and how many clean reps you got. The table converts the estimate into training loads.

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How to use your 1RM to program training

Once you have an estimated one-rep max, you can set sensible working weights as a percentage of it instead of guessing. As a broad guide: training above roughly 85% with low reps (1–5) builds maximal strength; the 67–85% range with moderate reps (6–12) is the classic hypertrophy zone most bodybuilding work lives in; and lighter loads below 67% with higher reps build muscular endurance. The percentage table above does that maths for you for whatever lift you've entered.

Why the estimate isn't a hard number

The calculator uses the Epley formula, which is reliable in the low-rep range and drifts upward the more reps you do — a set of 3 gives a tighter estimate than a set of 15, because grinding out high reps depends as much on conditioning as on raw strength. Treat the figure as a well-informed starting point for programming, not a score to chase. The real value is that you don't need to attempt a true single to know roughly where your max sits.

Standard barbell weights

A men's Olympic barbell is 20 kg (about 45 lb); a women's Olympic bar is 15 kg (about 35 lb); many gyms also have lighter 10 kg training bars. The plate loader defaults to these so the per-side maths comes out right — just confirm what your gym's bar actually weighs, since fixed-weight and specialty bars vary.

Questions
How accurate is the one-rep-max estimate?
It's most accurate from sets of about 2–6 reps. Above 8–10 reps the estimate tends to read high, so for programming purposes a heavier, lower-rep set gives a truer number than a long burnout set.
Why can't I always load an exact target weight?
You're limited by the smallest plates available. With standard plates the finest jump per side is usually 1.25 kg or 2.5 lb. If the loader leaves a remainder, that target can't be matched exactly without micro-plates — round to the nearest loadable weight.
Should I test a true max to use this?
No — that's rather the point. Attempting a genuine single carries more risk and needs experience and ideally a spotter. The estimator lets you work out training loads from a normal working set instead.
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This calculator is provided for general training convenience and gives approximate figures only. It is not medical, nutritional or coaching advice. Lift within your ability, use appropriate technique and safety equipment, and consult a qualified coach or healthcare professional before starting or changing a training programme.