Why can't I load an exact weight on a barbell?
Short answer: every plate goes on both sides of the bar, so the total can only move in steps of twice your smallest plate: 5 lb steps with 2.5 lb plates, and 2.5 kg steps with 1.25 kg plates. A target like 172 lb falls between 170 lb and 175 lb, and no mix of standard plates makes it. You load the nearest weight you can build, or add smaller plates.
Example: 80% of a 215 lb max
Your program calls for 80% of a 215 lb squat. Work it out:
- 215 × 80% = 172 lb.
- Take off the 45 lb bar: 127 lb of plates, so 63.5 lb on each side.
- The smallest standard plate is 2.5 lb, so each side can hold 62.5 lb or 65 lb, never 63.5 lb.
The two loads you can build are 170 lb (a 45, a 10, a 5 and a 2.5 on each side) and 175 lb (a 45 and two 10s on each side). 170 lb is 2 lb under the target and 175 lb is 3 lb over, so 170 lb is the nearest loadable weight.
The smallest jump is two of your smallest plates
Whatever plates you own, the smallest change you can make to the bar is one of your lightest plates on each side:
| Smallest plate | Smallest jump | Example loads |
|---|---|---|
| 5 lb | 10 lb | 185, 195 lb |
| 2.5 lb | 5 lb | 170, 175 lb |
| 1.25 lb | 2.5 lb | 170, 172.5 lb |
| 1 lb | 2 lb | 185, 187 lb |
| 1.25 kg | 2.5 kg | 100, 102.5 kg |
| 0.5 kg | 1 kg | 101, 102 kg |
So the question is never whether a number is "odd", only whether it sits on one of your steps. On a 45 lb bar with standard pound plates, every loadable total ends in 0 or 5.
Nearest loadable weight for common targets
Targets from percentages and programs, with the loads just below and just above, using standard plates on a 45 lb or 20 kg bar:
| Target | Load below (per side) | Load above (per side) |
|---|---|---|
| 172 lb | 170 lb (45, 10, 5, 2.5) | 175 lb (45, 10, 10) |
| 186 lb | 185 lb (45, 25) | 190 lb (45, 25, 2.5) |
| 191.25 lb | 190 lb (45, 25, 2.5) | 195 lb (45, 25, 5) |
| 202.5 lb | 200 lb (45, 25, 5, 2.5) | 205 lb (45, 35) |
| 102 kg | 100 kg (25, 15) | 102.5 kg (25, 15, 1.25) |
| 133 kg | 132.5 kg (25, 25, 5, 1.25) | 135 kg (25, 25, 5, 2.5) |
191.25 lb and 202.5 lb are 85% and 90% of 225 lb, which shows how often percentages miss the steps. The plate calculator lists both neighbors for any target, with the plates for each.
Round up or round down?
Taking whichever load is closer is the simplest rule, and with standard plates it is never more than half a step off: 2.5 lb or 1.25 kg. When the target sits exactly in the middle, like 202.5 lb between 200 and 205, you have to choose:
- Round down on heavy top sets and anything near your max, where a few extra pounds can cost a rep.
- Round up on lighter work, such as warm-ups and back-off sets, if you would rather not undershoot.
- Stay consistent. If you always round the same way, week-to-week progress in your log still compares like with like.
The closest loadable weight page explains the rule the LoadPR app uses.
No 2.5 lb plates in your gym
If the smallest plate on the rack is a 5, the bar moves in 10 lb steps. A 190 lb target with 45, 25, 10 and 5 lb plates can only be 185 lb (a 45 and a 25 on each side) or 195 lb (a 45, a 25 and a 5 on each side). That gap is why missing change plates hurt most on presses, where 10 lb is a big jump. The home gym plate calculator works from the plates you actually own, so it only shows loads you can build.
Who has 1 lb plates? Microplates
Small plates under 2.5 lb, often called microplates or fractional plates, are the real fix. Sizes depend on the set; common ones include 1.25 lb, 1 lb and 0.5 lb, and 0.5 kg in kilos.
- With a pair of 1.25 lb plates, 172 lb becomes 172.5 lb: a 35, a 25, a 2.5 and a 1.25 on each side.
- With a pair of 1 lb plates the step is 2 lb, so 186 lb still is not exact: the nearest loads are 185 lb and 187 lb (a 45, a 25 and a 1 on each side). An exact 186 lb needs half a pound more on each side.
- In kilos, two 0.5 kg plates on each side make 102 kg exactly: a 25, a 15 and two 0.5s on each side of a 20 kg bar.
For most lifts, rounding to the nearest step is fine. Microplates matter most when the jump between sessions is small compared with the weight, as on the overhead press and bench press.
A kilo program in a pound gym
Programs written in kilos rarely land on pound steps. 100 kg is 220.46 lb, and the nearest loads on a 45 lb bar are 220 lb (a 45, a 35, a 5 and a 2.5 on each side) and 225 lb (two 45s on each side). 220 lb is less than half a pound off, closer than any kilo-to-pound rule of thumb. Convert the weight first with the kg to lb converter, then round to your plates, not to the nearest 5 or 10 in your head.
Common mistakes
- Halving the gap wrong. To move the bar by 2 lb, each side needs 1 lb, not 2 lb.
- Forgetting the bar. Take the bar off the target before you split the plates between the sides.
- Rounding before converting. Convert kg to lb (or back) first, then round to your plates once; rounding twice stacks two errors.
- Assuming the gym has every plate. Without 2.5s or with only one pair, the steps get bigger. Count what is on the rack.
- Chasing the exact number. A 2 lb difference from the target is noise for most sets; load the nearest weight and lift.
FAQ
Why can't I load an exact weight on a barbell?
Plates go on in pairs, so the total moves in steps of twice your smallest plate: 5 lb with 2.5 lb plates, 2.5 kg with 1.25 kg plates. 172 lb falls between 170 lb and 175 lb.
What is the smallest jump you can make on a barbell?
Two of your lightest plates: 5 lb with 2.5 lb plates, 2.5 lb with 1.25 lb microplates, 2.5 kg with 1.25 kg plates and 1 kg with 0.5 kg plates.
Should I round a barbell weight up or down?
Take the closer load. On a tie, such as 202.5 lb between 200 lb and 205 lb, round down for heavy sets near your max and stay consistent from week to week.
Do 1 lb plates let me load any weight?
No. A pair of 1 lb plates makes 2 lb steps, so 186 lb on a 45 lb bar becomes 185 lb or 187 lb. An exact 186 lb needs 0.5 lb more on each side.
How do I load a 100 kg program weight with pound plates?
100 kg is 220.46 lb. On a 45 lb bar the nearest load is 220 lb: a 45, a 35, a 5 and a 2.5 on each side.