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ISBN Validator Examples

The ISBN Validator checks the format and check digit of ISBN-10 and ISBN-13 numbers, converts between formats, and decodes publisher and registration group information. Below are examples covering valid ISBNs, common errors, and conversions.

Valid ISBN-13 Examples

978-0-306-40615-7   ✓ Valid ISBN-13
  Prefix:           978 (Bookland)
  Registration:     0 (English language)
  Registrant:       306 (Publisher group)
  Publication:      40615
  Check digit:      7

978-3-16-148410-0   ✓ Valid ISBN-13
  Prefix:           978
  Registration:     3 (German language)
  Check digit:      0

979-8-88-640000-1   ✓ Valid ISBN-13
  Prefix:           979 (no ISBN-10 equivalent)
  Registration:     8 (Amazon KDP self-publishing)

Valid ISBN-10 Examples

0-306-40615-2       ✓ Valid ISBN-10
  Registration:     0 (English language)
  Registrant:       306
  Publication:      40615
  Check digit:      2

0-19-853453-1       ✓ Valid ISBN-10 (Oxford University Press)
0-7432-7356-7       ✓ Valid ISBN-10 (Simon & Schuster)
0-9752298-0-X       ✓ Valid ISBN-10 (check digit is X = 10)

Check Digit Calculation — ISBN-10

The ISBN-10 check digit uses a weighted sum where each digit is multiplied by its position (10 down to 1), and the total must be divisible by 11.

ISBN-10: 0-306-40615-?

Digits:    0  3  0  6  4  0  6  1  5  ?
Weights:  10  9  8  7  6  5  4  3  2  1

Sum = (0×10) + (3×9) + (0×8) + (6×7) + (4×6) + (0×5) + (6×4) + (1×3) + (5×2)
    = 0 + 27 + 0 + 42 + 24 + 0 + 24 + 3 + 10
    = 130

Check digit = (11 - (130 mod 11)) mod 11
            = (11 - (130 mod 11)) mod 11
            = (11 - 9) mod 11
            = 2

Complete ISBN-10: 0-306-40615-2  ✓

Check Digit Calculation — ISBN-13

ISBN-13 uses the EAN-13 algorithm: alternating weights of 1 and 3.

ISBN-13: 978-0-306-40615-?

Digits:   9  7  8  0  3  0  6  4  0  6  1  5  ?
Weights:  1  3  1  3  1  3  1  3  1  3  1  3  —

Sum = (9×1) + (7×3) + (8×1) + (0×3) + (3×1) + (0×3) + (6×1) +
      (4×3) + (0×1) + (6×3) + (1×1) + (5×3)
    = 9 + 21 + 8 + 0 + 3 + 0 + 6 + 12 + 0 + 18 + 1 + 15
    = 93

Check digit = (10 - (93 mod 10)) mod 10
            = (10 - 3) mod 10
            = 7

Complete ISBN-13: 978-0-306-40615-7  ✓

Invalid ISBN Examples

978-0-306-40615-8   ✗ Invalid — Check digit should be 7, not 8
                      (transcription error: last digit wrong)

0-306-40615-3       ✗ Invalid — Check digit should be 2, not 3

978-0-306-4061      ✗ Invalid — Only 12 digits; ISBN-13 requires 13

0-306-40615         ✗ Invalid — Only 9 digits; ISBN-10 requires 10

978-0-306-40615-7X  ✗ Invalid — Extra characters after check digit

ABC-0-306-40615-7   ✗ Invalid — Non-numeric characters in prefix

ISBN-10 to ISBN-13 Conversion

ISBN-10: 0-306-40615-2

Step 1: Drop the ISBN-10 check digit → 030640615
Step 2: Prepend 978 → 978030640615
Step 3: Calculate new ISBN-13 check digit → 7
Step 4: Result: 978-0-306-40615-7

ISBN-10: 0-9752298-0-X
Step 1: Drop check digit → 097522980
Step 2: Prepend 978 → 978097522980
Step 3: Calculate check digit → 4
Step 4: Result: 978-0-9752298-0-4

ISBN-13 to ISBN-10 Conversion

ISBN-13: 978-0-306-40615-7

Step 1: Must start with 978 (979 prefix has no ISBN-10 equivalent)
Step 2: Remove 978 prefix and check digit → 030640615
Step 3: Calculate ISBN-10 check digit → 2
Step 4: Result: 0-306-40615-2

ISBN-13: 979-8-88-640000-1
→ Cannot convert: 979 prefix has no ISBN-10 equivalent

Registration Group Codes

ISBN prefix 0 or 1 → English language
ISBN prefix 2      → French language
ISBN prefix 3      → German language
ISBN prefix 4      → Japan
ISBN prefix 5      → Russian language / former USSR
ISBN prefix 7      → China
ISBN prefix 80     → Czech Republic / Slovakia
ISBN prefix 81     → India
ISBN prefix 82     → Norway
ISBN prefix 83     → Poland
ISBN prefix 84     → Spain
ISBN prefix 85     → Brazil
ISBN prefix 86     → former Yugoslavia
ISBN prefix 87     → Denmark
ISBN prefix 88     → Italy
ISBN prefix 89     → South Korea
ISBN prefix 90     → Netherlands / Belgium (Dutch)
ISBN prefix 91     → Sweden
ISBN prefix 92     → International organizations
ISBN prefix 93     → India (additional)

Batch Validation Example

Input list:
978-0-7432-7356-5
0-7432-7356-7
978-0-7432-7356-6
9780743273565

Results:
978-0-7432-7356-5   ✓ Valid ISBN-13
0-7432-7356-7       ✓ Valid ISBN-10
978-0-7432-7356-6   ✗ Invalid — Check digit error (should be 5)
9780743273565       ✓ Valid ISBN-13 (same as first, no hyphens)

Paste any ISBN into the validator to instantly check its validity, see the check digit calculation, and convert between ISBN-10 and ISBN-13 formats.

Frequently Asked Questions

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