# Plate calculator: what goes on each side of the bar.

This plate calculator works out which plates go on each side of the bar for a target weight, from your bar, your collars and the plates your gym actually has. It works in kilograms or pounds, picks the fewest plates, and finds the nearest weight you can load when the exact one isn’t possible.

Use the calculator on the page: https://trainaq.com/tools/plate-calculator. For planning what to load in the gym. It assumes you have enough pairs of each plate and that they fit on the sleeve, and it cannot know your bar: check its marking or weigh it. Use collars, and a spotter or safety bars for heavy lifts.

## How do you work out the plates for a barbell?

A plate calculator takes the bar and collars off your target, then halves what is left: that is the weight for each side. For 100 kg on a 20 kg bar, each side carries 40 kg, a 25 and a 15. When your plates can’t make the exact amount, it finds the nearest weight they can.

- Bars of 20, 15 or 10 kg, 45 or 35 lb, or your own
- The plates your gym has, from 25 kg down to 0.25 kg, or 55 lb down to 1.25 lb
- Collars counted when you use them
- The fewest plates per side, or the nearest weight you can load

## How does this plate calculator work?

Enter the target, pick your bar, add the collars if you use them and tick the plates you have. The calculator subtracts the bar and collars, halves the rest and searches every combination of your plates for the fewest that make it, heaviest first. If none do, it shows the nearest weights.

### 1. Set the target and the bar

Type the total you want, bar included. Choose a 20 kg bar, the weight of IPF powerlifting and IWF men’s bars, a 15 kg IWF women’s bar, a 10 kg bar, 45 or 35 lb, or type your own bar’s weight.

- If your bar is unmarked, weigh it once
- Switching units converts what you typed

### 2. Add the collars

Competition collars weigh 2.5 kg each under IPF and IWF rules, so a competition bar with collars comes to 25 kg. USA Powerlifting counts lightweight plastic or spring collars as zero, so leave collars at 0 if you use those.

- USA Powerlifting allows 5 lb collars with a 45 lb bar at local meets

### 3. Tick the plates you have

Switch on each plate size your gym has in pairs. The calculator starts with 25, 20, 15, 10, 5, 2.5 and 1.25 kg, the discs the IPF uses in competition, or 45, 35, 25, 10, 5 and 2.5 lb.

- The other sizes, 2 kg down to 0.25 kg, give finer steps
- It assumes you have enough pairs of each size

### 4. Load from the inside out

The result lists one side, heaviest plate first, which is the order to load it: IPF and IWF rules both put the heaviest discs innermost. The diagram shows the same side from the centre of the bar outwards.

- When the exact weight is impossible, you also see the next lighter and heavier loads

## What is the formula for plates per side?

Each side carries the target minus the bar and both collars, divided by two. The loaded weight is the bar, plus both collars, plus twice the plates on one side. The calculator then picks the fewest plates that add up to each side’s weight exactly, or the nearest weights above and below.

- Weight per side: `S = (T − B − 2 × C) ÷ 2`
- Weight loaded: `T = B + 2 × C + 2 × (p₁ + p₂ + … + pₙ)`
- Fewest plates: `p₁ ≥ p₂ ≥ … ≥ pₙ from your plates, with p₁ + … + pₙ = S and n as small as possible`

- T: target weight; B: the bar; C: one collar (0 for clips)
- S: the weight on each side; p: the plates on one side, heaviest first
- Kilograms or pounds throughout, never mixed

## Which plates and bars do the rules specify?

In IPF powerlifting the bar and collars weigh 25 kg together, and discs run from 25 kg to 1.25 kg, with lighter ones only for records. IWF weightlifting uses a 20 kg men’s bar, a 15 kg women’s bar and discs from 25 kg to 0.5 kg. Both colour 25, 20 and 15 kg plates red, blue and yellow.

| Item | IPF powerlifting | IWF weightlifting | USA Powerlifting |
| --- | --- | --- | --- |
| Bar | 20 kg; with collars, 25 kg | Men 20 kg, women 15 kg | 20 kg; 45 lb at local meets |
| Collars | 2.5 kg each, always used | 2.5 kg each, two per bar | 2.5 kg each; 5 lb with a 45 lb bar |
| Discs | 25, 20, 15, 10, 5, 2.5 and 1.25 kg | 25, 20, 15, 10, 5, 2.5, 2, 1.5, 1 and 0.5 kg | 25 to 1.25 kg; 45, 35, 25, 10, 5 and 2.5 lb locally |
| Record discs | 1, 0.5 and 0.25 kg | None listed | 0.5 and 0.25 kg |
| Colours | 25 red, 20 blue, 15 yellow; 10 and under any | 25 red, 20 blue, 15 yellow, 10 green, 5 white | 25 red, 20 blue, 15 yellow; 10 and under any |
| Loading | Heaviest innermost | Heaviest first, lighter outwards | Heaviest innermost |

Sources: IPF Technical Rulebook 2026, sections 2.3 and 2.4; IWF Technical and Competition Rules & Regulations 2020, section 3.3.3; USA Powerlifting Rulebook v2026.2, sections 2.3 to 2.5. USA Powerlifting also allows 55 lb plates.

## What does a worked example look like?

Say you want 142.5 kg on a 20 kg bar with 2.5 kg competition collars. Bar and collars come to 25 kg, which leaves 117.5 kg, or 58.75 kg a side. With standard plates that is 25 + 25 + 5 + 2.5 + 1.25: five plates on each side, heaviest first.

- 101 kg on a 20 kg bar can’t be made with plates down to 1.25 kg: the nearest loads are 100 kg and 102.5 kg
- In pounds, 315 lb on a 45 lb bar is three 45 lb plates a side
- 61 kg on a 15 kg women’s bar with 2.5 kg collars is 20 + 0.5 a side, with IWF discs

## Why not just load the heaviest plates first?

With the IPF and IWF kilogram sets, heaviest first always gives the fewest plates: we checked every weight up to 300 kg a side. Other sets trip it up. With 35 lb plates, 60 lb a side takes two plates, 35 + 25, where heaviest first uses three: 45 + 10 + 5.

- With 1.25 kg and 0.5 kg plates but no 0.25 kg, heaviest first can’t make 1.5 kg a side; three 0.5 kg plates can
- With the record discs (1, 0.5 and 0.25 kg) added, 2 kg a side is two 1 kg plates, where heaviest first takes 1.25 + 0.5 + 0.25
- So the calculator searches every combination and, among the shortest, keeps the heaviest plates
- If you prefer heaviest first anyway, the total is the same; only the plates differ

## How accurate is the weight on the bar?

As accurate as your equipment. Competition plates must weigh within 0.25% of their face value, or 10 g for small ones, and a competition bar within 50 g of 20 kg under USA Powerlifting rules. Gym plates have no such rule, and an unmarked bar can weigh anything, so weigh yours once if you can.

- IPF and USA Powerlifting discs: 20 kg and heavier at most 6 cm thick, 15 kg and lighter at most 3 cm
- The largest discs may be at most 45 cm across
- IPF sleeves are 50 to 52 mm across, and the calculator doesn’t check that your plates fit on them
- USA Powerlifting does not allow kilogram and pound plates on the same bar in competition

## How do coaches use plate loading with clients?

Coaches set the load for each set, and clients have to build it from the plates in their gym. In Trainaq you put weights and reps on each set of a client’s workout; clients see them, with last time’s numbers, in the free Trainaq app, log in kilograms or pounds, and get an alert when they set a PR.

- Each set can carry its own weight and reps
- PR alerts cover weight, estimated 1RM, reps and duration
- You see every logged set and PR from their sessions

[The workout builder in Trainaq](https://trainaq.com/features/workout-builder)

## Sources

1. [International Powerlifting Federation. Technical Rulebook 2026, effective 1 March 2026: section 2.3, bars and discs, and section 2.4, collars.](https://www.powerlifting.sport/fileadmin/ipf/data/rules/technical-rules/english/2026_IPF_Technical_Rulebook__effective_01_March_2026__v3.pdf)
2. [International Weightlifting Federation. Technical and Competition Rules & Regulations 2020: section 3.3.3, barbell (bar, discs and collars). Copy hosted by the Indian Weightlifting Federation.](https://iwlf.in/wp-content/uploads/2021/03/IWF_TCRR_2020.pdf)
3. [USA Powerlifting. Rulebook, version 2026.2: section 2.3, bar; 2.4, plates; 2.5, collars. 2026.](https://www.usapowerlifting.com/assets/general/PDFs/USAPL-Rulebook-v2026.2.pdf)

## FAQ

### How much does a barbell weigh?

An IPF powerlifting bar weighs 20 kg, as does the IWF men’s weightlifting bar, and the IWF women’s bar 15 kg. Competition collars add 2.5 kg each. USA Powerlifting allows a 45 lb bar, about 20.4 kg, at local meets. Technique and specialty bars vary, so check the marking or weigh yours.

### Should I count the collars?

Count them if they have real weight. Competition collars weigh 2.5 kg each, so a pair adds 5 kg to the bar. USA Powerlifting counts lightweight plastic or spring collars as zero. Enter the weight of one collar, and the calculator adds both before it works out the plates.

### Why can’t I load my exact weight?

Your smallest plate sets the step. With 1.25 kg as the smallest, the total moves in 2.5 kg steps, because each side needs the same plate. For finer steps you need smaller plates, such as 0.5 kg or 0.25 kg. Until then, the calculator offers the nearest loads above and below your target.

### Does the order of the plates matter?

Yes. Load the heaviest plates first, nearest the centre of the bar, then lighter ones outwards, and load both sides the same. IPF, IWF and USA Powerlifting rules all require this order, so referees can read every plate. Put the collars on last, before you lift.

### Can I mix kilogram and pound plates?

In a gym you can, if you add them up carefully, but this calculator works in one unit at a time to keep the sums exact. USA Powerlifting does not allow pound and kilogram plates on one bar in competition. To mix, convert each pound plate: 1 lb is 0.45359237 kg.

### Why does the calculator choose the fewest plates?

Fewer plates means less to load and more room left on the sleeve. Among answers with the same number of plates, it keeps the heaviest. If your gym is short of a size, untick it and the calculator works around it with the plates you do have, or offers the nearest loads.

## Related

- [One-rep max calculator](https://trainaq.com/tools/one-rep-max-calculator): Loads from 100% down to 50% of your max
- [RPE chart](https://trainaq.com/tools/rpe-chart): The load for any reps and RPE
- [DOTS calculator](https://trainaq.com/tools/dots-calculator): Compare totals across body weights
- [Workout builder](https://trainaq.com/features/workout-builder): Sets, reps and weights for each client

Source: https://trainaq.com/tools/plate-calculator