First in, first out costing for reloading components
You rarely pay the same price twice for the same powder. First in, first out is a simple rule for knowing what each batch actually cost.
Published November 2, 2026
The rule
First in, first out (FIFO) means you use your oldest purchase first. When it runs out, you move on to the next one. Each batch is charged what its components actually cost, not today’s price and not a blended average.
It also matches how a careful bench tends to run: older components get used before newer ones, and you know which purchase went into which batch.
A worked example
You bought two 1 lb jugs of the same powder:
| Purchase | Paid | Grains | Per grain |
|---|---|---|---|
| First | $32 | 7,000 | 0.457¢ |
| Second | $42 | 7,000 | 0.600¢ |
Now you load 100 rounds at a time, using 40 grains per round, or 4,000 grains per batch.
| Batch | Comes from | Powder cost |
|---|---|---|
| 1 | 4,000 gr of the first jug | $18.29 |
| 2 | 3,000 gr of the first jug, 1,000 gr of the second | $13.71 + $6.00 = $19.71 |
| 3 | 4,000 gr of the second jug | $24.00 |
Batch 2 straddles the two jugs, and that’s the case people tend to get wrong by hand. A batch can draw on as many purchases as it takes.
Why not use an average?
An average of the two jugs gives 0.529¢ per grain, or $21.14 for every batch. The total comes out about the same over time, but the average hides what’s going on: it can’t tell you that batch 3 cost nearly a third more than batch 1.
Keep lots apart
The worked example assumes the same powder in both jugs, but a purchase is more than a price. Keep the lot number with each one. Lots of the same powder can behave differently, so it pays to know which lot went into which batch, and to work up a load again from published data when a lot changes. If a maker ever issues a notice about a lot, you can find out straight away which rounds it went into.
Doing it by hand or by app
A spreadsheet can do this, but the sums get fiddly once a batch crosses two purchases. In AmmoLoader, recording a batch takes the components out of your inventory oldest first and works out the cost per round from what you paid for those purchases, fees included.
The figures here are made-up examples for the arithmetic, not prices or load data. AmmoLoader doesn't recommend charge weights. Always follow published load data from the powder and bullet makers.