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A tool for macronizing Latin text.

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NOTE: Maccer is no longer in development.
Please use Johan Winge's excellent Latin Macronizer instead.


  1. Paste or write plain Latin text into the box above.
  2. Click māc!.
  3. Insert macrons where missing (✖) or uncertain (✒, ✪, ❡) by placing a hyphen (-) after each vowel that should be marked as long, then click a- › ā.
  4. Remove flags by clicking flags.

The offline version, which is customizable and can process longer texts, is available for download via the folder icons at the top of this page, or via the GitHub project page, where further instructions can be found.

Problems? Click for the "Issues" page, where you can ask a question or report a bug.

Unknown word.
Ambiguous: uncertain vowels marked with a tilde (~).
Guessed based on frequency.
Prefix or enclitic detected attached to a known word.
Invalid characters detected.


  • Text can be de-macronized by clicking ō › o.
  • If any text is selected, commands will be applied only to the selection.
  • Click to undo the most recent command, but this will also undo all changes since then. Click it again to redo the command and all changes after it.
  • Use comments (C-style // or /* */) to exclude any words that should not be macronized, e.g. a passage in another language.
  • Markdown formatting is supported. Click the preview icon in the text area to render.


Coming Soon

  • Enlargement of the word key with a full list of inflected lexical entries, thanks to the ongoing work of Keith Alexander Woodell of Numen - The Latin Lexicon.

Q & A

1. A lot of words get “✖” flags instead of macrons. This program is stupid!

Maccer operates based on a list of Latin word forms, currently numbering over 35,000, generated from digital texts already marked with macrons. It does not generate inflected forms based on principal parts. The advantages of the former method are simplicity and expandability; the disadvantage is that the word list is limited by the corpus of already-macronized source texts, which so far is very small. Individual forms can be added manually to the word key, e.g. abiēgnō, but entire words in all their inflections cannot be added in one stroke, as in abiēgnus, -a, -um.

Consequently, Maccer inserts macrons were possible (i.e. for forms already in the key with no similar possibilities such as hōc and hoc), but it is up to you to check the words Maccer has guessed, and to macronize those it does not know. Even of words that are not flagged as problematic, care should be taken, as the source texts are great but not perfect.

The good news is that the more Maccer is used, the smarter it will become. After you have filled in the gaps by hand, Maccer can then analyze your hand-corrected text and add the previously unknown word forms to the key. Ideally the online version would allow anyone to improve the word key in this way, but as I’m not a web programmer, the only way to do this is by sending me texts with macrons (whether created with the help of Maccer or not), and I’ll incorporate them into the word key.

2. So this word key is based on online texts? But those are full of errors!

Yes, the texts I have found that have vowel quantity marked range from almost perfect to worse than nothing (viz. OCR scans), and it would be impossible to correct every single mistake in them. However, with the help the scripts Analyze and Repair Key that detect and fix possible errors in the word key, along with some human input, this automated process becomes much less haphazard: for example, hidden long vowels, non-classical orthography, and words incorrectly marked where the correct form is known (e.g. amicus and amīcus) are all detected and corrected under the supervision of the user.

3. Offline version: What’s all this about .txt files? Can’t I use Maccer in Word?

No. See the answer to the next question for an imperfect solution.

4. Web version: I can’t copy text from Word without losing all the formatting!

Web applications have trouble reading Word formatting, so here it is not supported. But some formatting can be preserved by following these steps:

  1. Plug your Word file into the Word to Markdown Converter.
  2. Copy the resulting Markdown-formatted text, paste it above, and macronize it.
  3. Generate formatting via the preview button, or for more customizability, via Pandoc.

5. Web version: This program is really slow!

I’m not a programmer, least of all a web programmer, so I did not imagine Maccer running on a webpage until late in its development, when I found out Lua scripts could be run on the web via the Lua VM. I thought it would be worth a try, and here is the result. The web version would be faster if it were ported to pure JavaScript, but it is what it is.

6. Web version: This program doesn’t work on [insert book title here]!

The web version simply cannot macronize texts of about 2000 words or more. The offline version has no such limitation.

Contact me (see above) if you have any further questions.

Thanks to the creators of:

✪ The source texts, chiefly:

Woordenboek Latijn/Nederlands, hosted at Logeion, and the TLL as invaluable aids regarding hidden long vowels

LualuapowerLua VMutf8.luaEpicEditor and demosSlate theme