Roman numerals: convert numbers, chart, and lessons

A free Roman numerals converter and reference tool. Type a number from 1 to 3,999,999 or a Roman numeral and it converts instantly in both directions, showing a live breakdown of how each symbol is built (1984 = M + CM + LXXX + IV). It also writes any year or date in Roman numerals, handles the vinculum overline for large numbers, and adds optional lessons, a quiz, and a tap-to-read Roman clock. Works offline, no sign-up.

How to use it

1
Type either side

Enter a number on the left or a Roman numeral on the right. The other box fills in as you type, with a breakdown below.

2
Read the breakdown and chart

See exactly which symbols make up the number, and use the always-visible reference chart with the seven symbols and six subtraction pairs.

3
Convert years and dates

Open the Years & dates tab to decode famous years or turn any year or full date into Roman numerals — handy for tattoos and monuments.

4
Learn and practise

Tap the speaker to hear any result, follow the lessons, take the quiz, or read the Roman clock to master the system.

Convert numbers to Roman numerals and back in one click

Converter

Type a number (1–3,999,999) or a Roman numeral — it converts as you type

Tip: press / to focus the box, Enter to listen. Add ?n=1984 to the link to share a number.

Years & dates

Decode famous years, or turn any year or date into Roman numerals

Decode this year
—

Your year in Roman numerals
Any date in Roman numerals

Popular for tattoos, monuments, and copyright lines. Format: day · month · year.

Tiles builder

Drag symbols into the tray — the tool folds them into the correct Roman numeral

I1
V5
X10
L50
C100
D500
M1000
Drag a tile here to begin
Value: 0

Four in a row? It folds into a subtraction pair (IIII → IV).

Build this number
—

Step-by-step lessons

Six guided lessons with stars, achievements, and a certificate at the end

Roman clock

Tap an hour — hear it and see its Roman form

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💡 Did you know? Most real clocks write 4 as IIII instead of IV. Clockmakers keep the old Roman style for visual balance.

Quiz

Play rounds of ten — build streaks and unlock achievements

Achievements

Unlock all six

⭐ First number Convert your first number.
🔤 The seven Finish lesson 1.
➖ Subtraction pro Finish lesson 3.
🔥 Ten in a row Reach a streak of ten in the quiz.
⏰ Clockmaker Solve three clock challenges.
🏛️ Time traveler Decode five famous years.
📄 Printable worksheet

Generate a problem sheet with an answer key

🏅 Certificate

Finish all six lessons to unlock the certificate.

What makes it special

Instant two-way converter: numbers to Roman and Roman to numbers, from 1 to 3,999,999
Live breakdown shows how each numeral is built — for example 1984 = M + CM + LXXX + IV
Vinculum (overline) support for numbers above 3999, plus a day · month · year date converter
Always-visible reference chart, voice pronunciation, and a shareable link for any result
Forgiving input: non-standard forms like IIII are read and the canonical IV is suggested
Optional step-by-step lessons, a quiz, a Roman clock, and a printable worksheet

Frequently asked questions

Who is this tool for?

Anyone working with Roman numerals — students and teachers, readers decoding book chapters or movie copyright years, people planning a tattoo or anniversary date, and kids learning the system through the lessons and quiz.

What is the largest number it converts?

It handles 1 to 3,999,999. Up to 3999 uses the classic letters (the biggest is MMMCMXCIX = 3999). Above that, a bar over a letter — the vinculum — multiplies it by 1000, so V with an overline is 5000.

Why do some clocks write four as IIII instead of IV?

Clockmakers have done this for centuries for visual balance — IIII on the left mirrors VIII on the right, so the face reads more evenly. Both forms are historically correct. The Clock mode uses the classic IIII style to show the tradition.

Does it accept non-standard numerals like IIII or VV?

Yes. The converter reads them and shows the value, then suggests the canonical form (IIII → IV, VV → X) with one tap to apply it — so you always learn the standard spelling.

Does my progress save?

Your stars, achievements, and the name you type are stored in this browser via localStorage, so they are still here next time. You can clear everything any time from the Settings panel.

Can I use it offline?

Yes. Once the page has loaded, the converter and every mode work without a connection. Voice pronunciation uses your browser's built-in speech engine, which is usually available offline too.

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Who is this tool for?
🎓 Students 📚 Educators & Teachers 👨‍👩‍👧 Parents & Families
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