ISBN Validator & Converter
Local ProcessingValidate ISBN-10 or ISBN-13 and convert between them.
How It Works & Processing Standards
Validate ISBN-10 or ISBN-13 and convert between them.
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Current Limits
- Maximum input length: 100,000 characters
The last digit of an ISBN is a check digit. Choose convert under "Task" to prefix an ISBN-10 with 978 and recompute the check digit, or choose a check to see whether a number is valid.
What You Can Do
- 10 ↔ 13 conversion
- Adds 978 and recomputes the check digit to make an ISBN-13.
- ISBN-10 check
- Weights 10 to 1 must sum to a multiple of 11 (X = 10).
- ISBN-13 check
- Alternating 1 and 3 weights must sum to a multiple of 10.
How to Use ISBN Validator & Converter
- 1Choose a taskConvert, or check ISBN-10 or ISBN-13.
- 2Enter the ISBNHyphens and spaces are fine.
- 3Read the resultSee the converted number or validity.
Examples
ISBN-10 → ISBN-13
Input: 0-306-40615-2
Result: 9780306406157
ISBN-13 check
Input: 978-0-306-40615-7
Result: ✓ Valid
ISBN-10 with a wrong check digit
Input: 0-306-40615-3
Result: ✗ Invalid
Common Use Cases
- Converting an older ISBN-10 into ISBN-13 for bookstore or library systems
- Catching typos in ISBNs entered into a book list
Frequently Asked Questions (FAQ)
Why does the last digit change?
ISBN-10 and ISBN-13 compute check digits differently, so after adding 978 the last digit is recalculated. That is why the 2 in 0-306-40615-2 becomes 7. The task converts ISBN-10 → ISBN-13 only.