Barbell Plate Loading Calculator
What to put on each side, searched exhaustively — because biggest-plate-first can fail outright on a weight that is perfectly loadable.
Plates are counted in pairs, because a barbell is loaded symmetrically — one pair of 25s adds 50 kg to the total, not 25. Collars are ignored; add their weight to the bar if yours are heavy enough to matter. Nothing is uploaded.
Biggest plate first is not always right
Everyone loads a bar by grabbing the heaviest plate that still fits. On a full rack that is both correct and efficient. Take one denomination out of the set — which is what a home gym looks like — and it can fail on a weight that is perfectly loadable. With no tens on the rack, 90 kg wants 1×20 + 1×15 per side; greedy takes a 25, needs ten, cannot make it, and stalls 2.5 kg short.
| Target | Biggest-first gets | Best loading | Plates |
|---|---|---|---|
| 70 kg | 1×25 | 1×25 | 1 |
| 90 kg | 1×25 + 1×5 + 1×2.5 — 2.5 kg short | 1×20 + 1×15 | 2 |
| 95 kg | 1×25 + 1×5 + 1×2.5 — 5 kg short | 1×20 + 1×15 + 1×2.5 | 3 |
| 110 kg | 1×25 + 1×20 | 1×25 + 1×20 | 2 |
| 140 kg | 2×25 + 1×5 + 1×2.5 — 2.5 kg short | 1×25 + 1×20 + 1×15 | 3 |
Greedy loading is only guaranteed optimal when each denomination divides the next, and a real plate set nearly has that property until something is missing from it. On a full rack every row above loads first time and with the fewest plates — which is exactly why the habit survives, and why it fails without warning when it finally does.
And not every weight exists
Plates go on in pairs, so the smallest change a bar can make is twice the smallest plate — 2.5 kg on a set with 1.25s, and coarser without them. A full rack can make 113 different totals up to 300 kg; the gapped set manages 34. Asking for 21 kg on a 20 kg bar is not a rounding problem, it is an impossibility.
| Target | On a full rack | Plates |
|---|---|---|
| 60 kg | 1×20 | 1 |
| 90 kg | 1×25 + 1×10 | 2 |
| 100 kg | 1×25 + 1×15 | 2 |
| 140 kg | 2×25 + 1×10 | 3 |
| 180 kg | 3×25 + 1×5 | 4 |
Which is worth knowing before writing a programme in percentages: the numbers a spreadsheet produces are continuous and the bar is not, so something has to give and it is always the spreadsheet. The tool searches every combination rather than guessing, so when it says a weight cannot be made, that is a fact about your plates and not a failure of method.
How to use
- Enter the total you want and your bar weight.
- Enter how many PAIRS of each plate you own.
- Read the loading, and whether biggest-first would have found it.
- Check the nearby weights to see what your plates can actually make.
Frequently asked questions
How do I work out what plates to load?
Subtract the bar, halve what is left, and make that from your plates — each pair adds twice its own weight to the total. A pair of 25s on a 20 kg bar gives 70 kg, not 45.
Is biggest plate first always right?
No, and this is the part worth knowing. It is guaranteed optimal only when each plate size divides the next, which a real set stops doing as soon as something is missing from it.
Can you show a case where it fails?
With no 10s on the rack, 90 kg needs a 20 and a 15 per side. Biggest-first takes a 25, is then left needing exactly 10, cannot make it, scrapes together 5 and 2.5 and stalls two and a half kilos short of a weight that was perfectly loadable.
Does that happen on a full rack?
No. Given a complete set with plenty of every denomination, biggest-first always works and always uses the fewest plates — which is exactly why the habit survives, and why it fails without warning when it finally does.
Why can I not load any round number?
Because plates go on in pairs, so the smallest change a bar can make is twice the smallest plate — 2.5 kg on a set with 1.25s. Anything between two loadable weights does not exist, and 21 kg on a 20 kg bar is not a rounding problem but an impossibility.
How many weights can my set make?
Fewer than you would think, and far fewer with a gap in it. A full rack reaches 113 different totals up to 300 kg; a sparse home set with no 10s or 1.25s manages 34. The tool lists the neighbours so you can see the spacing.
Does this account for collars?
No — add their weight to the bar figure if yours are heavy enough to matter. Competition collars are 2.5 kg each and absolutely do; the plastic spring clips on most home bars do not.
Does this send anything anywhere?
No. Every figure is computed in your browser, and nothing is uploaded or stored.
🔒 This tool runs entirely in your browser. Nothing you enter is uploaded, logged, or stored.