Plate Math

Know what goes on the bar.

Type a weight and see exactly which plates go on each side, drawn to scale. Then estimate your max, ramp your warm-up, run 5/3/1 and log every set.

Load the bar See how it works
Free, no sign-up Saved on your device Kilograms or pounds
Plate Math Saved
kg

Steps of 2.5 kg, one pair of your smallest plates.

Bar
Adds 2.5 kg a pair.

Set it up once. Then just lift.

Plate Math learns your gym, then answers the one question you have between sets.

Tell it your plates

Count the pairs on your rack and pick your bar. Every answer from then on uses only what you have.

Type a weight

The plates for each side appear on a barbell drawn to scale. If it can't be made, you get the closest weights either side.

Lift and log

Tick off your warm-ups, log your working sets and watch your estimated max climb week to week.

Everything between sets.

Six tools that share one plate inventory, so every number you see is one you can actually load.

Only the plates you own.

Tell it you have two pairs of 20s and it never asks for three. It tries the heaviest plates first, then searches every combination you own for an exact match.

81.1%

RPE built in.

Five reps at RPE 8 is 81.1% of your max. Enter how hard a set felt and get a better estimate.

5/3/1, rounded for you.

Four weeks of sets from your training max, each one loadable.

Watch your max climb.

Log sets in seconds. Plate Math charts your estimated one-rep max for each lift and calls out every personal record.

Closest weights, both ways.

Asked for 21 kg? You'll see 20 and 22.5, one tap to load either.

Competition colours.

Red 25s, blue 20s, yellow 15s. The weight is printed on every plate.

kg / lb

Your units, your bar.

A full pound plate set with 45 and 35 lb bars, or 20, 15 and 10 kg. Custom bars too.

Questions

How does it choose the plates?
It takes as many of the heaviest plate as fit, limited by how many pairs you own, then works down the sizes. If that misses, it checks every combination you own for an exact match. If none exists, it shows the nearest weights you can load below and above.
Why does the step change from 2.5 kg?
The minus and plus buttons move by one pair of your smallest plate. With 1.25 kg plates that's 2.5 kg. Add 0.5 kg fractional plates under My plates and the step drops to 1 kg.
Which 1RM estimate should I trust?
None is exact. Plate Math averages Epley, Brzycki and Lombardi, which agree closely between 2 and 10 reps. For heavy top sets, the RPE method is usually closer, because it accounts for how many reps you had left.
What is a training max in 5/3/1?
A slightly reduced 1RM, usually 85 to 90% of your true max. Every 5/3/1 percentage is taken from it, which keeps the work submaximal so you can keep adding weight for months. Week 4 is a lighter deload.
Do collars count toward the weight?
Turn on Collars if you use competition collars, which weigh 2.5 kg a pair (5 lb in pounds mode). Leave it off for spring clips, which weigh next to nothing.
Where is my data stored?
Only on this device, in your browser's storage. Nothing is uploaded. Use Export CSV in the Log to keep a copy or move it to a spreadsheet.