·5 min read·Blog

Roman Numeral Converter: How Roman Numerals Work and Where They're Used

Roman numerals show up on clock faces, movie sequel titles, Super Bowl numbers, and copyright dates. Here's the complete system — rules, common values, and a free converter.

The seven symbols

SymbolValueOrigin
I1One finger/tally
V5Hand (V shape of thumb and fingers)
X10Two V's (two hands)
L50Half of C (100)
C100Centum (Latin for 100)
D500Half of M (1000)
M1000Mille (Latin for 1000)

The additive and subtractive rules

Roman numerals are generally written largest to smallest, left to right, and you add the values:

  • VIII = 5 + 1 + 1 + 1 = 8
  • XVII = 10 + 5 + 1 + 1 = 17
  • CXXX = 100 + 10 + 10 + 10 = 130

The subtractive notation rule: when a smaller symbol appears before a larger one, subtract it. Only six specific subtractive combinations are valid:

  • IV = 4 (not IIII)
  • IX = 9 (not VIIII)
  • XL = 40 (not XXXX)
  • XC = 90 (not LXXXX)
  • CD = 400 (not CCCC)
  • CM = 900 (not DCCCC)

Combinations outside these six are not valid — IIX (trying to write 8) or VX (trying to write 5) are incorrect. Only one smaller symbol can precede a larger one in a subtractive pair.

Common values reference

NumberRomanNumberRoman
4IV40XL
9IX90XC
14XIV400CD
19XIX500D
24XXIV900CM
29XXIX1000M
Super Bowl LVIII58MMXXVI2026

Where Roman numerals appear today

  • Super Bowl. The NFL uses Roman numerals for Super Bowl numbers — Super Bowl LVIII was played in February 2024 (58th Super Bowl). The NFL skipped Roman numerals for Super Bowl 50 because "L" looked awkward as branding.
  • Copyright years. Credits in movies, TV shows, and books often display the copyright year as Roman numerals — a tradition meant to obscure the production date (no longer effective given the internet, but the tradition persists).
  • Clock faces. Analog clocks and watches frequently use Roman numerals. Note: on most clocks, 4 o'clock is written as IIII (additive), not IV (subtractive) — this is a historical convention for clock aesthetics, not standard Roman numeral notation.
  • Royalty and papal names. King Charles III, Pope John Paul II — sequential numbering with Roman numerals is standard for monarchs and popes sharing a name.
  • Outlines and lists. Formal outlines use Roman numerals for top-level sections (I, II, III) with capital letters for subsections (A, B, C).
  • Building cornerstones and public art. The year of construction on buildings, bridges, and monuments is often inscribed in Roman numerals.

Converting large numbers

Standard Roman numerals top out at 3,999 (MMMCMXCIX). Ancient Romans handled larger numbers with overbars (a bar over a numeral multiplied it by 1,000) or vinculum notation — but these aren't in common use today.

For any number conversion — year, sequence number, or any integer — use the free Roman numeral converter. It converts both directions (number to Roman and Roman to number) instantly.

Related tools


Written by Achraf A., founder of TheFreeAITools.

Browse by category

Not sure which tool you need? Start with a category.

Everything you can do — for free

No software to buy. No account to create. Just open a tool and get it done.

Work with images

Compress photos before sending them by email, resize pictures for social media, remove backgrounds, or pick the perfect color for a design project — all without installing any app.

Edit and format text

Count words and characters in an essay, compare two documents side by side, convert text to different formats, or generate placeholder text for a presentation.

Stay safe online

Create a strong unique password in one click, check how secure a password is, encode or decode data, and generate secure tokens — your data never leaves your device.

Calculate anything

BMI, loan repayments, unit conversions, date differences, and dozens of other everyday calculations — no spreadsheet or formula knowledge required.

The Free AI Tools is a free collection of 221+ online tools that work directly in your web browser — no download, no installation, no account required. Whether you need to compress an image for email, count words in an essay, generate a strong password, create a QR code for your business, or format JSON for development — you will find a simple, free tool here.

Every tool is privacy-first: your files, text, and data never leave your device. Tools cover image editing, text processing, developer utilities, security & encoding, SEO & web, design & CSS, and more.

☕ Support Us