Clothify tools

Clothing Size Run and Inventory Calculator

Turn your size weights into whole-piece quantities that add up to your exact production run.

Free, no account
Adds up exactly
CSV export

Turn weights into whole pieces

Enter the run and a weight per size, pick a curve shape, or try the example.

Pieces for every size, XS to 3XL
Size curve and running total
A run that adds up exactly

How to use it

Enter the run
Type the total number of pieces for one product in one color.
Weight each size
Use past orders, preorder counts or percentages. Put 0 for any size you are skipping.
Read the curve
See whole pieces per size, the running total and any size that rounded to zero.
Take it with you
Download the CSV or copy a summary to paste into your supplier order.

Worked example: 37 pieces centered on M

This is the run the Try an example button loads. The weights are illustrative, not a forecast for any brand.

A brand plans 37 shirts with weights XS 5, S 15, M 30, L 25, XL 15, 2XL 10, 3XL 0. The weights add up to 100, so M’s ideal share is 37 × 30 ÷ 100 = 11.1 pieces. Nobody can order a tenth of a shirt, so every size has to become a whole number.

Rounding each share down places 34 pieces and leaves 3. Those go to the sizes with the largest decimals left over, so the final run is XS 2, S 6, M 11, L 9, XL 5, 2XL 4, 3XL 0. It adds up to exactly 37, and 3XL stays at zero because its weight is zero.

Total pieces: 37
Sizes with pieces: 6 of 7
Largest size: M, 11 pieces
Placed by rounding: 3 pieces

The example run: XS 2, S 6, M 11, L 9, XL 5, 2XL 4, 3XL 0.

XS: 2 pieces
S: 6 pieces
M: 11 pieces
L: 9 pieces
XL: 5 pieces
2XL: 4 pieces
3XL: 0 pieces

Size M, step by step

Total pieces37
timesM weight30
divided bySum of all weights100
equalsIdeal share, rounded down11.1 → 11

M’s remainder of 0.1 is too small to win one of the 3 leftover pieces, so M stays at 11.

The formula

Each size gets its share of the run, then the largest remainder method turns the shares into whole pieces without losing or adding one.

Ideal share for one size

Total piecestimesSize weightdivided bySum of all weightsequalsIdeal share

Sum of all weights: So weights can be counts, percentages or a ratio such as 1 : 3 : 4 : 3 : 1.

Round every ideal share down to a whole piece. Count the pieces still missing from the run.

Give one missing piece each to the sizes with the largest decimal remainders. When two remainders tie, the size listed first wins.

Share in the table is the size weight divided by the sum of weights. Displayed shares can add to 99.9% or 100.1%; the pieces always add up exactly.

What it leaves out

It splits one product in one color. Repeat it for each color or style.
Supplier minimums, pack sizes and size availability are not applied.
The weights are yours. An example curve is not a demand forecast or a benchmark.
It does not judge fit. Check the supplier’s size chart and a physical sample.
On a small run a size with a low weight can round to zero pieces.
Sizes run from XS to 3XL. Larger or kids’ sizes are not covered.

Method and sources

The allocation uses the largest remainder method, also called the Hamilton method. It is plain arithmetic: no data about any market is involved. The weights in the example and in the curve shapes are illustrative.

Before you order, check the cash this run ties up with the POD versus bulk calculator and approve a physical sample. Values you type stay in your browser and are not saved.

How largest remainder rounding works

The same 37 piece example in three steps. This is how the calculator keeps every run exact, and you can repeat it by hand with any weights.

Find each size’s ideal share
37 pieces × weight ÷ 100, the sum of the weights.
- XS1.85
- S5.55
- M11.1
- L9.25
- XL5.55
- 2XL3.7
Round every share down
That places 34 pieces and leaves 3 to hand out. The decimals left over are the remainders.
- XS1remainder 0.85
- S5remainder 0.55
- M11remainder 0.1
- L9remainder 0.25
- XL5remainder 0.55
- 2XL3remainder 0.7
Give the rest to the largest remainders
One piece each to XS, S, 2XL. When two remainders tie, the smaller size goes first.
- XS2+1
- S6+1
- M11kept
- L9kept
- XL5kept
- 2XL4+1
Total 37 pieces, exactly as ordered. 3XL had a weight of 0 and get none.

Questions

How many of each size should I order?

There is no universal size mix, so the best weights come from your own customers: past orders, preorders or a waitlist where people pick a size. If you have none yet, keep the first run small or sell print on demand until you see which sizes sell. Then enter those counts here as weights.

How do I turn size percentages into quantities?

Multiply the total run by each size’s percentage to get its ideal share. Because shares come out as decimals, round them with the largest remainder method so the sizes still add up to the run. Enter the percentages as weights above and the calculator does both steps.

Why does my size run not add up after rounding?

Normal rounding treats each size on its own, so the errors pile up. Ten pieces split evenly across three sizes are 3.33 each, and rounding gives 3, 3 and 3, which is only nine. The largest remainder method gives the tenth piece to one size, so the run stays at ten.

What is the largest remainder method?

It rounds every share down to a whole number, counts how many pieces are still missing, then gives one each to the shares with the biggest decimal remainders. The total always matches exactly. Ties go to the size listed first.

What if a size rounds to zero pieces?

On a small run a size with a low weight can have an ideal share below one piece and lose the remainder contest. The calculator lists those sizes. Raise the run or that size’s weight, or decide to skip the size in this order.

Should I offer every size from XS to 3XL?

That is your call, but every size you add takes pieces from the others. On a small run fewer sizes keeps more pieces in each, while print on demand lets you list every size without holding stock. Set a weight of 0 for any size you leave out.