ISBN-13 to ISBN-10 Converter

How ISBN-13 to ISBN-10 Converter Works?

The ISBN-13 to ISBN-10 Converter works by confirming the 978 prefix, removing the prefix and the old check digit, and computing a new modulus 11 check character. ISBN-13 values with the 979 prefix have no ISBN-10 equivalent.

1. 1Validate the ISBN-13 check digit.
2. 2Confirm the ISBN-13 starts with 978; stop if it starts with 979.
3. 3Keep digits 4 to 12 (9 digits).
4. 4Weight the 9 digits 10 down to 2 and compute (11 − (S mod 11)) mod 11.
5. 5Write 10 as X and append the check character.

ISBN-13 to ISBN-10 Converter Formula

The ISBN-13 to ISBN-10 formula is ISBN-10 = d₄…d₁₂ + (11 − (Σ (14 − i)·dᵢ mod 11)) mod 11.

core = d₄d₅…d₁₂
S = 10·core₁ + 9·core₂ + … + 2·core₉
check = (11 − (S mod 11)) mod 11,  10 → X

• core is the 9-digit ISBN body.

Prefix 978 confirmed
Core = 080442957
S = 199
S mod 11 = 1
Check = (11 − 1) mod 11 = 10 → X
ISBN-10 = 0-8044-2957-X

ISBN-13 to ISBN-10 Converter Conversion Table

The ISBN-13 to ISBN-10 conversion table lists 978-prefix ISBNs with their ISBN-10 equivalents and 1 ineligible 979 example.

What is ISBN-13 to ISBN-10 Converter?

An ISBN-13 to ISBN-10 Converter is a tool that converts a 978-prefix ISBN-13 back into the 10-character ISBN format. The converter recomputes the modulus 11 check character, which can be X.

Agencies began issuing 979-prefix ISBNs after the 978 range filled up in countries such as France and the United States, so only 978 numbers convert.

What are the uses of ISBN-13 to ISBN-10 Converter?

There are 3 main uses of the ISBN-13 to ISBN-10 Converter, including legacy systems, marketplace lookups, and citation formats.

• Legacy systems: Older library and inventory systems still store 10-character ISBNs.
• Marketplace lookups: Sellers search older listings indexed by ISBN-10.
• Citation formats: Researchers match references that cite an ISBN-10.