How the plate calculator works
Loading a barbell should take a second, not a math problem. Dial in your target weight on the Plates tab and the app subtracts the bar weight, halves what remains, and shows the exact stack of plates for one side of the bar — drawn as a color-coded visual so you can read it at a glance. It supports both kilograms and pounds, standard 20 kg / 45 lb Olympic bars as well as lighter training bars, and it always favors the fewest, heaviest plates so loading is fast. Read the full how-to-use guide for tips on custom bar weights and available plate sets.
Barbell math, made simple
The core formula is straightforward but easy to get wrong mid-workout: plates per side = (target weight − bar weight) ÷ 2. From there you work down from the heaviest plate available. For example, on a 20 kg bar loaded to 100 kg, you need 80 kg split across two sides — 40 kg per side — which is one 20 kg, one 15 kg, and one 5 kg plate on each end. The app does this instantly for any weight. If you want to understand the logic yourself, our barbell math explainer walks through it step by step.
Olympic (IWF) color-coded plates
The visual barbell uses the International Weightlifting Federation color standard — the same colors used in international competition — so a loaded bar in the app matches a loaded bar in a properly equipped gym:
Once you learn the colors, you can read any barbell in under a second from across the room — no counting plates one by one.
More than a calculator
PR tracker
Log a personal record for any lift and the app keeps your best weights and history in one place, so you always know what to load for an opener, a second attempt, or a new max.
Percentage calculator
Coaches program in percentages — “work up to 80% of your 1RM.” The % Calculator tab turns any percentage of your max into an exact weight, and then into the exact plates.
Warmup pyramids & rest timer
Get an automatic warmup ramp toward your working set, and use the built-in Timer to keep rest periods consistent between sets.
Frequently asked questions
Is it free?
Yes. The plate calculator, PR tracker, percentage calculator, and timer are all free to use in your browser — no account required. See more answers in the full FAQ.
Do I need to install anything?
No. It runs directly in your mobile or desktop browser. On iPhone and Android you can also add it to your home screen so it opens like a native app and works offline.
Does it work in pounds?
Yes — switch between kilograms and pounds anytime, with plate sets and bar weights for both.
Where is my data stored?
Your PRs and settings are saved locally on your own device and never leave your phone. See our privacy policy for details.