Call Number Sorter
Paste Library of Congress or Dewey Decimal call numbers, one per line, and get them in shelf order — the way a library files them — with each one broken into its class, Cutter numbers, date and volume. Lines that are not call numbers are set aside, not lost. Runs in your browser. Free, no sign-up.
Library of Congress (QA76.73.J38 S53 2019) or Dewey (005.133 SCH).
Paste call numbers, one per line, to put them in shelf order.
How to Use the Call Number Sorter
- 1. Paste call numbers. One per line, as they appear on the spine label or in the catalogue. Spaces and the periods before Cutters are optional, and a slash can stand for a line break:
641.5/Corn. - 2. Check the classification. The sorter detects whether the list is Library of Congress or Dewey; choose one yourself if a short list is misread.
- 3. Read the shelf order. Each call number is numbered by its place on the shelf and broken into labelled parts, so you can see why it files where it does.
- 4. Copy the sorted list. Any line that could not be read is listed separately and added to the end of the copied list, so nothing goes missing.
How Library of Congress Call Numbers File
Read an LC call number from left to right. QA76.73.J38 S53 2019 has a class (QA), a class number (76.73), two Cutter numbers (.J38 and S53) and a date. Shelf order compares the parts in that order:
| Part | Rule | In shelf order |
|---|---|---|
| Class letters | Alphabetically; a single letter files before the double letters that begin with it. | Q · QA · QC · QL · R |
| Class number | As a whole number, then the decimal digit by digit. | QA 70.5 · QA 75 · QA 76 · QA 76.15 · QA 76.2 · QA 77 |
| Cutter number | The letter alphabetically, then the digits as a decimal: .E3 is .3 and .E35 is .35. | .E3 · .E35 · .E359 · .E4 |
| Date | Earlier years first. A date files before a second Cutter in the same position. | J38 · J38 2019 · J38 S53 2015 · J38 S53 2019 |
| Volume, copy | By number, so v.2 files before v.10. | v.1 · v.2 · v.10 |
Under all of it is the rule librarians call nothing before something: QA76 files before QA76.1, and QA76.73.J38 before QA76.73.J38 S53.
How Dewey Decimal Call Numbers File
A Dewey call number is a three-digit class number, an optional decimal, and a book mark — often the first letters of the author's surname (005.133 SCH) or a Cutter–Sanborn number (005.133 S386). The whole number files numerically; everything after the point files digit by digit, which is the step most people get wrong:
Decimals, digit by digit
398 · 398.1 · 398.12 · 398.2
Then the book mark
641 Bett · 641.5 Corn · 641.5 Wolk · 641.555 Ray · 641.594 Muns · 641.5945 Food · 641.596 Mont · 641.65 Dese
641.555 files before 641.596 because 5 is less than 9 in the second decimal place — not because 555 is less than 596 — and 641.65 comes after both. When the numbers match, the book marks file alphabetically, and a Cutter–Sanborn mark is read like an LC Cutter, so S386 files before S39.
What the Sorter Does Not Know
- Separate collections. Prefixes such as Ref., Folio or J are kept and grouped first, alphabetically. Libraries usually shelve those collections apart, often in another room.
- Mixed lists. A list is read as all Library of Congress or all Dewey, because the two are shelved in separate sequences. Sort a mixed list in two batches.
- Local conventions. Libraries differ on details such as where supplements go and whether copies file before volumes. The sorter applies the standard rules above; your library's shelving guide is the final word.
- Other schemes. NLM call numbers (classes QS–QZ and W) follow the LC pattern and sort correctly. Superintendent of Documents (SuDocs) and UDC numbers are not supported.
Frequently Asked Questions
- How do you put Library of Congress call numbers in order?
- Compare them part by part: the class letters alphabetically, the class number as a whole number and then its decimal digit by digit, each Cutter by its letter and then as a decimal, and finally dates and volumes in order. Paste a list above to see it done, with every part labelled.
- Why does QA76.73 come before QA76.8?
- The digits after the decimal point are read one at a time, as a decimal fraction: .73 is less than .8 because 7 is less than 8. Treating 73 as a whole number larger than 8 is the most common shelving mistake.
- What is a Cutter number?
- A letter followed by digits that places a book among others on the same subject, usually by author or title; the system is named after the librarian Charles Ammi Cutter. In .J38, J is the initial and 38 is read as the decimal .38, so .J38 files before .J4.
- How do you sort Dewey Decimal call numbers?
- By the three-digit class number first, then the decimal one digit at a time — 398.12 before 398.2 — then the book mark alphabetically. A number with nothing after the decimal point files before the same number with a decimal.
- Does a call number without a date file first?
- Yes. Under the nothing-before-something rule, QA76.73.J38 files before QA76.73.J38 2019, and a call number that ends sooner files before a longer one that matches it up to that point.
- Can I sort Library of Congress and Dewey numbers together?
- Not meaningfully, because the two systems are shelved in separate sequences. The sorter reads a list as one scheme, so split a mixed list and sort each part, or choose the scheme yourself.