📚 ISBN Validator & Converter

Professional ISBN validation tool that verifies checksum accuracy, converts between ISBN-10 and ISBN-13 formats, and provides proper hyphenation. Essential for publishers, librarians, and book retailers working with book catalogs and inventory systems.

Enter ISBN-10 or ISBN-13 with or without hyphens. Examples: 978-0-306-40615-7, 0306406152, 9780306406157
Choose which ISBN format(s) to display in results
Select how to format the hyphens in ISBN display
Display step-by-step checksum calculations and conversion process

ISBN Validation Results:

📚 ISBN VALIDATED

Valid ISBN with Successful Conversion

Checksum verified • Format conversion available

📖 Input Analysis

Original Input:
978-0-306-40615-7
Detected Format:
ISBN-13
Clean Digits:
9780306406157
Length:
13 digits
✓ Valid ISBN format detected

ISBN-13 Valid

978-0-306-40615-7

Checksum: 7 ✓

🔄

ISBN-10 Converted

0-306-40615-2

Checksum: 2 ✓

✂️

Clean Format

9780306406157

Digits only

🧮 Checksum Verification

/* ISBN-13 Checksum Calculation */
Positions: 9 7 8 0 3 0 6 4 0 6 1 5 [7]
Weights: 1 3 1 3 1 3 1 3 1 3 1 3
Products: 9+21+8+0+3+0+6+12+0+18+1+15 = 93
Check digit: (10 - (93 % 10)) % 10 = 7 ✓
/* ISBN-10 Conversion */
Remove 978 prefix: 0306406157 → 030640615
Weights: 10×0 + 9×3 + 8×0 + 7×6 + 6×4 + 5×0 + 4×6 + 3×1 + 2×5 = 132
Check digit: (11 - (132 % 11)) % 11 = 2 ✓

📋 Usage Information

Format
Both Valid
Conversion
Available
Hyphenation
Standard

💡 Professional Use:

This ISBN is valid for library catalogs, publishing systems, and book inventory management. Both formats are internationally recognized.

How to Use This ISBN Validator & Converter

How to Validate and Convert ISBNs:

  1. Enter your ISBN in any format (with or without hyphens)
  2. Select your preferred output format (both formats, ISBN-13, ISBN-10, or clean digits)
  3. Choose hyphenation style (standard, minimal, or none)
  4. Optionally enable detailed analysis to see checksum calculations
  5. Click "Validate & Convert ISBN" to process your input
  6. Copy results or download detailed report for your records

Supported Formats: ISBN-10 (0123456789, 0-123-45678-9), ISBN-13 (9780123456789, 978-0-123-45678-9), with flexible hyphenation and spacing.

How It Works

Understanding ISBN Validation and Conversion:

This tool implements the official ISBN algorithms used worldwide for book identification:

ISBN-10 Validation Process:

  1. Format Check: Verify 10 characters (9 digits + check digit which can be X)
  2. Checksum Calculation: Multiply each digit by weight (10, 9, 8, ..., 2)
  3. Modulo 11: Sum all products, divide by 11, remainder must equal check digit
  4. Special Case: If remainder is 10, check digit is 'X'

ISBN-13 Validation Process:

  1. Format Check: Verify 13 digits starting with 978 or 979
  2. Alternating Weights: Multiply digits by alternating weights (1, 3, 1, 3, ...)
  3. Modulo 10: Sum products, subtract from next multiple of 10 for check digit
  4. EAN Compatibility: Same algorithm as EAN-13 barcodes

Format Conversion:

  • ISBN-10 to 13: Add '978' prefix, recalculate check digit using ISBN-13 algorithm
  • ISBN-13 to 10: Remove '978' prefix (if present), recalculate using ISBN-10 algorithm
  • Limitation: Only ISBN-13 starting with '978' can convert to ISBN-10
  • Modern Standard: All new ISBNs use 13-digit format since 2007

Professional Applications:

  • Library Systems: Validate catalog entries and ensure data integrity
  • Publishing: Convert formats for different distribution platforms
  • Retail: Verify barcode accuracy and format consistency
  • Data Processing: Clean and standardize ISBN databases

When You Might Need This

Frequently Asked Questions

What's the difference between ISBN-10 and ISBN-13?

ISBN-10 uses 10 digits with the last being a check digit (0-9 or X), while ISBN-13 uses 13 digits starting with 978 or 979. ISBN-13 became the standard in 2007, but both are still valid. ISBN-13 provides more numbering space and is compatible with EAN barcodes used in retail.

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

Yes, every ISBN-10 can be converted to ISBN-13 by adding the 978 prefix and recalculating the check digit. However, not all ISBN-13s can convert to ISBN-10 - only those starting with 978 can be converted back. ISBNs starting with 979 have no ISBN-10 equivalent.

Why does my ISBN validation fail even though it looks correct?

The most common reason is an incorrect check digit. ISBNs use mathematical checksums to detect errors - ISBN-10 uses modulo 11, ISBN-13 uses modulo 10. Even if the format looks right, a single wrong digit will cause validation to fail. Check for typos or transcription errors.

How does hyphenation work in ISBNs?

ISBN hyphens separate the registration group (country/region), registrant (publisher), publication (title), and check digit. Proper hyphenation requires knowledge of the ISBN registration system structure maintained by the International ISBN Agency. This tool uses standard hyphenation patterns.

Is this tool suitable for professional library or publishing use?

Yes, this tool implements the official ISBN algorithms from the International ISBN Agency standards. It's suitable for professional validation, format conversion, and hyphenation tasks. However, critical production systems should implement additional verification layers and consult official ISBN databases for complete validation.