ISBN-10 to ISBN-13 Converter

Turn 978 plus first 9 ISBN digits into full 13 digit code.

What it does

ISBN-13 codes are EAN-13 barcodes starting with 978 or 979. Converting from ISBN-10 drops the old check digit, keeps the first nine, prepends 978, then recomputes the EAN check with 1/3 weights.

The tool above takes those 12 digits and returns new check, full 13, and weighted sum. The default 978030640615 matches ISBN-10 0-306-40615-2, so the page opens showing check 7. Type new twelves to update all three results.

Weights run odd once, even three times from the left. Here odds sum to 27, evens to 22 times 3 for 66, total 93, check (10 minus 3) mod 10 is 7. Full reads 9780306406157.

This checks arithmetic only. It never proves registration or edition assignment. Prefix 979 needs the same math with its own digits.

This page shows the method, one full hand checked example at 978030640615, a reference table, and practice checks that run through the tool.

How to use

1. Take ISBN-10 and drop its last check char.
2. Prepend 978 to the first 9 digits for 12 total.
3. Type those 12 digits here.
4. Read New check digit.
5. Read Full ISBN-13 as your 12 plus check.
6. Register prefixes with ISBN agency separately.

Formula

978

Bookland prefix for converted ISBN-13.

first 9

ISBN-10 without its old check.

check

New 13th digit.

ISBN-10 check can be X for ten, but conversion drops it before math. Only digits enter here.

Worked example

Reference table

Limits

• Arithmetic only. No registry proof.
• 978 prefix here. 979 needs its own 12.
• 12 digits to start.
• X check dropped before math.

Common mistakes

• Keeping old ISBN-10 check for 13 digits of input.
• Forgetting 978 prefix.
• Using UPC 3/1 weights instead of EAN 1/3.
• Pasting dashes that change length. This tool strips them first.
• Assuming pass means registered edition.

Try it yourself

Quick checks. Answers sit tucked under each question.

Questions

Sources

• GS1: Barcodes
• GS1 US: Barcodes

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