What is the difference between the scrap allowance and the reserve?

The scrap allowance covers expected bad prints and reprints and is calculated on the batch. The reserve covers unexpected extra needs and is calculated on the demand including scrap. Together they determine the quantity to request.

Can I reuse numbers that were not printed in the next batch?

Generally not. If an allocated number is given to another unit there is a risk of clashing with the first record. Record unused numbers as cancelled and allocate a new range for the next batch; the exact rule depends on the system you depend on.

Why should each line get a single consecutive range?

If every printer works in its own range the numbers cannot collide and no coordination between lines is needed. When a line has a recording error, the range also shows which numbers are affected.

Why does the digit string of the first number matter?

The length of the digit string is fixed, and capacity depends on it (6 digits = 1,000,000 numbers). If the plan exceeds the capacity the tool reports an error and shows the numbers that remain.

Are the values I enter sent anywhere?

No. The calculation runs in your browser; the values are not transmitted to a server or stored.

Serial number batch plan

Enter the batch size, scrap and reprint allowance, reserve rate and number of printers. See how many serial numbers to request and the consecutive ranges per line starting at your first number; read the reporting note for numbers that will go unused.

Free tool · Serialisation

Batch sizeitemsThe number of good items that will be printed and used.

Scrap / reprint allowance%Percent of the batch: allowance for bad prints, unreadable labels and reprints.Reserve rate%Percent of the demand including scrap: allowance for unexpected reprints and extra needs.Printers / linescountThe number of printers or lines the numbers are distributed to in ranges.First serial numberA prefix and a fixed-length digit string, e.g. SN000001. The digit string length is kept; the ranges start here.

Block rounding (optional)countIf numbers are handed to the printer in blocks, the block size; each line's quantity is rounded up to a multiple of it. 0 = no rounding.

The calculation runs in your browser; the values you enter are not sent anywhere.

Serial numbers to request

10,710

SN000001 – SN010710

Breakdown

Batch (good items): 10,000
Scrap / reprint allowance: + 200
Demand including scrap: 10,200
Reserve: + 510
Numbers to request: 10,710
Numbers actually allocated: 10,710
Numbers not expected to be printed (reserve + rounding): 510
Start of the next batch: SN010711
Numbers left under this prefix: 989,289

Consecutive ranges per line

Serial number ranges per line
Line	First number	Last number	Count
1	SN000001	SN003570	3,570
2	SN003571	SN007140	3,570
3	SN007141	SN010710	3,570

Reporting unused numbers

The fate of every allocated number should be recorded: used, printed and scrapped, or never printed. Numbers allocated but not printed because of reserve and block rounding must not be issued again in the next batch; that is why the next start number begins after the last allocated number.

The system you depend on (a trading partner, a national tracking system or your own database) may require unused or cancelled numbers to be reported. Check the deadline and format in that system's rules; this tool does not produce a report.

Sequential numbers can be guessed. Where unpredictability is required (for example pharmaceutical serialisation) generate the numbers randomly.

demand = ⌈batch × (1 + scrap%)⌉ · to request = ⌈demand × (1 + reserve%)⌉ · per line = to request / lines (remainder to the first lines) · with a block size, rounded up to a multiple

The scrap and reserve allowances are your assumptions; the tool does not measure them. The plan is only a numerical estimate: number allocation, usage records and reporting obligations must be handled separately under the rules of the system you depend on. It is not legal or technical advice.

Let's set up number allocation, printer distribution and unused-number records together with your line.

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How to use it

A
Enter the batch size, scrap allowance, reserve rate, number of lines and the first serial number.
B
Read the quantity to request and the consecutive ranges per line.
C
Copy the plan or download the CSV; apply the reporting note for unused numbers.

How the quantity to request is calculated

The scrap and reprint allowance is added first to the number of good items to be printed: demand = batch × (1 + scrap). The reserve rate is then added to that demand: to request = demand × (1 + reserve). Each step is rounded up, so the requested quantity never falls short.

Percentages are handled with integer arithmetic, so there is no floating-point rounding error. For example a batch of 10,000 with 2% scrap and 5% reserve needs 10,200 and then 10,710 numbers.

Consecutive ranges per line

The requested numbers are split as evenly as possible among the lines; leftover numbers go to the first lines one by one. Each line gets one consecutive range from the first number onwards, so ranges do not overlap and leave no gaps between them.

If numbers are handed to your printer in blocks, enter the block size: each line's quantity is rounded up to a multiple of it. That increases the number of allocated numbers; the increase is shown separately in the output.

Unused numbers

Reserve, scrap and block rounding mean some numbers are never used. What matters is keeping a record of these numbers and never giving the same number to another item.

Some systems require unused or cancelled numbers to be reported. Check the rules of the system you depend on; this tool does not report anything.

FAQ

What is the difference between the scrap allowance and the reserve?: The scrap allowance covers expected bad prints and reprints and is calculated on the batch. The reserve covers unexpected extra needs and is calculated on the demand including scrap. Together they determine the quantity to request.
Can I reuse numbers that were not printed in the next batch?: Generally not. If an allocated number is given to another unit there is a risk of clashing with the first record. Record unused numbers as cancelled and allocate a new range for the next batch; the exact rule depends on the system you depend on.
Why should each line get a single consecutive range?: If every printer works in its own range the numbers cannot collide and no coordination between lines is needed. When a line has a recording error, the range also shows which numbers are affected.
Why does the digit string of the first number matter?: The length of the digit string is fixed, and capacity depends on it (6 digits = 1,000,000 numbers). If the plan exceeds the capacity the tool reports an error and shows the numbers that remain.
Are the values I enter sent anywhere?: No. The calculation runs in your browser; the values are not transmitted to a server or stored.

Let's set up number allocation with your line

From the batch plan to distributing numbers to the printer, and from unused-number records to aggregation, we handle the serialisation flow end to end.

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