ISBN Converter

Easily convert between ISBN-10 and ISBN-13

Easily convert between International Standard Book Number (ISBN) formats. Convert from ISBN-10 to ISBN-13 or from ISBN-13 to ISBN-10 with automatic check digit calculation for accurate conversion.

How to Use - Easy Conversion in 3 Steps

Using the ISBN converter is very simple:

Enter ISBN
Enter the ISBN-10 or ISBN-13 you want to convert. Hyphens and spaces will be automatically processed.
Click Convert Button
Click the "Convert" button to automatically detect the format and perform the conversion.
Copy Result
The converted ISBN will be displayed. Use the "Copy" button to easily copy it to the clipboard.

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ISBN Conversion

Practical Use Cases

The ISBN converter tool can be used in various situations:

1. Library Systems

If an old library system only supports ISBN-10, you can convert new books' ISBN-13 to ISBN-10 for registration. Also useful when you need to manage both formats during system migration.

2. Bookstores & Second-hand Bookstores

When inventory management systems or POS systems require a specific ISBN format, you can easily convert using this tool. Also helpful when migrating data between multiple systems.

3. E-commerce Sites & Online Bookstores

Useful for unifying product databases, integrating with external APIs, and enhancing search functionality when you need to handle different ISBN formats.

4. Database Management

When organizing or migrating book databases and you need to maintain both ISBN-10 and ISBN-13, you can batch convert using this tool.

5. API Integration & System Integration

When external book information APIs or databases require a specific ISBN format, pre-converting with this tool enables smooth integration.

What is ISBN?

ISBN (International Standard Book Number) is a unique numbering system for identifying books. It is assigned to books published worldwide and used for distribution and inventory management.

ISBN-10 (Old Format)

The 10-digit ISBN format used before 2007. The last digit is the check digit (verification number), which can be 0-9 or X. Format: X-XXXX-XXXX-X

ISBN-13 (Current Format)

The 13-digit ISBN format that became standard on January 1, 2007. It is compatible with EAN (European Article Number) product codes and can also be used as barcodes. Usually starts with "978" or "979". Format: XXX-X-XXXX-XXXX-X

How ISBN Conversion Works

Converting ISBN-10 to ISBN-13

Take the first 9 digits from ISBN-10 (excluding the check digit)
Add "978" (GS1 prefix) at the beginning to make 12 digits
Calculate the 13th digit using the ISBN-13 check digit formula

Example: ISBN-10: 4-12-345678-X → ISBN-13: 978-4-12-345678-9

Converting ISBN-13 to ISBN-10

Ensure the ISBN-13 starts with "978"
Take the 9 digits after "978"
Calculate the 10th digit using the ISBN-10 check digit formula

Example: ISBN-13: 978-4-12-345678-9 → ISBN-10: 4-12-345678-X

Conversion Limitation ISBN-13 numbers starting with "979" cannot be converted to ISBN-10 because the 979 prefix was introduced after the ISBN-10 system was phased out.

Check Digit Calculation

The ISBN check digit is a verification number used to detect input errors or corruption.

ISBN-10 Check Digit Formula

For the first 9 digits, multiply each digit by (10-position), sum them up, divide by 11, and subtract the remainder from 11. If the result is 10, "X" is used.

Example: ISBN-10 4-12-345678-X
Calculation: (4×10) + (1×9) + (2×8) + (3×7) + (4×6) + (5×5) + (6×4) + (7×3) + (8×2) = 165
165 ÷ 11 = 15 remainder 0
11 - 0 = 11 → Check digit: X (representing 10)

ISBN-13 Check Digit Formula

For the first 12 digits, multiply odd-position digits by 1 and even-position digits by 3, sum them up, divide by 10, and subtract the remainder from 10.

Example: ISBN-13 978-4-12-345678-9
Calculation: (9×1) + (7×3) + (8×1) + (4×3) + (1×1) + (2×3) + (3×1) + (4×3) + (5×1) + (6×3) + (7×1) + (8×3) = 131
131 ÷ 10 = 13 remainder 1
10 - 1 = 9 → Check digit: 9

Frequently Asked Questions

What is the difference between ISBN-10 and ISBN-13?

ISBN-10 is the old 10-digit format used before 2007. ISBN-13 is the new 13-digit format that became standard on January 1, 2007, and is compatible with EAN product codes. ISBN-13 starts with "978" or "979".

Can all ISBN-13 be converted to ISBN-10?

No, only ISBN-13 starting with "978" can be converted to ISBN-10. ISBN-13 starting with "979" cannot be converted because there is no corresponding ISBN-10. This is because the 978 prefix numbers were exhausted and the 979 prefix was introduced.

What is a check digit?

The check digit is the last digit of the ISBN, a verification number used to detect input errors or number corruption. ISBN-10 uses 0-9 or X, and ISBN-13 uses 0-9. It is automatically generated based on a specific formula.

Are hyphens required?

Hyphens are not required. This tool automatically processes ISBNs regardless of whether they have hyphens or spaces. However, results are displayed with hyphens for readability.

What does the "X" in ISBN-10 mean?

When the check digit of ISBN-10 becomes 10, it would be 2 digits, so the Roman numeral "X" (meaning 10) is used. This keeps the ISBN at 10 digits.

Is this tool free to use?

Yes, this ISBN converter tool is completely free and can be used as many times as you want. No user registration required.

Is the entered ISBN data saved?

No, this tool runs in your browser and the entered data is not sent to any server. All processing is completed within your browser, protecting your privacy.

What happens if I enter an incorrect ISBN?

The tool automatically validates the format and check digit of the entered ISBN. If an invalid ISBN is entered, an error message will be displayed informing you of the issue.