Barbell plate calculator

How to use the calculator

1. Take a target weight — for example a working weight from the working weights calculator.
2. Enter the bar weight. A standard Olympic bar is 20 kg, a women's bar 15 kg.
3. Choose a plate set: the gym's standard preset, the minimal one, or your own list of pairs (for example 5; 5; 10; 20).
4. Press "Calculate".

The result is the plates per side, the total weight and the difference from the target when an exact set is impossible.

Where the algorithm comes from

Plates are loaded symmetrically: the same set on each side. So one side carries (target weight − bar weight) / 2. The greedy algorithm builds that sum from the heaviest plates to the lightest: 25, then 20, 15 and so on, until the remainder is smaller than the smallest plate or the pairs run out.

If an exact weight cannot be loaded — for example a target of 100.6 kg with a 20 kg bar: one side needs 40.3 kg, but 25 + 15 gives only 40 — the calculator shows a total of 100 kg and a difference of 0.6 kg. The algorithm never returns a weight above the target.

How to check it by hand

Example: target weight 100 kg, Olympic bar 20 kg, standard set.

1. Per side: 100 − 20 = 80; 80 / 2 = 40 kg.
2. Greedily from the heavy end: 25 → remainder 15; 20 does not fit; 15 → remainder 0.
3. Per side 25 + 15 kg, total 100 kg — exact.

Limitations

• The greedy algorithm loads from the heavy end; for an unusual set a more accurate combination may exist — compare the difference.
• The weight of clamps and collars (up to 2.5 kg each) is not counted.
• Check the real plate denominations in your gym — the presets are approximate.
• A working weight from the working weights calculator is an estimate: its error carries over into the loading.
• Cheap plates can weigh 2–3 % more or less than their marking.