Roman Numeral Converter

Roman Numeral Reference

Common Examples

What Are Roman Numerals?

Roman numerals are the number system of ancient Rome, built from seven letters: I (1), V (5), X (10), L (50), C (100), D (500), and M (1,000). Numbers are formed by combining these symbols, mostly by adding values from left to right. The system has no zero and no place value — a symbol's position matters only for the small set of subtractive pairs like IV (4).

Though replaced by Hindu-Arabic numerals for arithmetic more than a thousand years ago, Roman numerals never fully disappeared. You still meet them on clock faces, book chapter headings, film credits, monarch and pope names (Elizabeth II), major sporting events, and building cornerstones. Reading them is a small but durable piece of cultural literacy.

The Rules

Three rules cover nearly everything. First, write symbols from largest to smallest and add (XVI = 10 + 5 + 1 = 16). Second, a smaller symbol before a larger one subtracts (IX = 10 − 1 = 9) — but only the six standard pairs above, and only one smaller symbol may precede. Third, no symbol repeats more than three times in a row, and V, L, D are never repeated or used subtractively.

Step-by-Step: Converting 1984

• Step 1 — Thousands: 1984 contains one 1,000 → M. Remainder: 984.
• Step 2 — Hundreds: 984 contains 900, written subtractively as CM. Remainder: 84.
• Step 3 — Tens: 84 contains 80, written as LXXX (50 + 10 + 10 + 10). Remainder: 4.
• Step 4 — Ones: 4 is written subtractively as IV. Result: MCMLXXXIV.

Worked Examples

Example 1: 49 → XLIX

40 = XL (50 − 10); 9 = IX (10 − 1). Combined: XLIX.

Example 2: 2026 → MMXXVI

2,000 = MM; 20 = XX; 6 = VI. Combined: MMXXVI.

Example 3: MMXXIV → decimal

Read left to right: MM = 2,000; XX = 20; IV = 5 − 1 = 4. Total: 2,024.

Common Mistakes

• Writing IIII for 4: the standard form is IV; IIII survives only on some clock faces by tradition.
• Inventing pairs like IC for 99: only the six standard subtractive pairs are valid — 99 is XCIX.
• Repeating V, L, or D: VV is never correct; 10 is X, never VV.
• Reading strictly right-to-left: evaluate left to right, subtracting only when a smaller value precedes a larger one.

Frequently Asked Questions

Did the Romans have zero? No — Roman numerals have no symbol for zero, which is one reason the system was so awkward for arithmetic.

What is the largest number? Conventionally 3,999 (MMMCMXCIX). Larger values used a bar over symbols to multiply by 1,000, but there was never a single standard.

Why do some clocks show IIII instead of IV? Tradition and visual balance with VIII on the opposite side of the dial; the reasons are historical rather than mathematical.

Are Roman numerals still used officially? Yes — in outlines, film copyright dates, monarch numbering, and formal documents, among other places.

Subtractive Pairs: Quick Reference

Six pairs do all the subtracting in the modern standard form. Only I, X, and C may be subtracted, and each may be subtracted only from the next two symbols above it:

This is why 99 is XCIX (90 + 9), never IC — each decimal place is written out on its own, so IC and IL are always wrong.

Dates as Roman Numerals

A full date is converted part by part — day, month, year separately — with dots or middle dots between the parts, the style used for tattoos and engravings:

• 14 February 2026 → XIV.II.MMXXVI (day-first, European order)
• February 14, 2026 → II.XIV.MMXXVI (month-first, US order)
• With middle dots: XIV · II · MMXXVI

Verify each part on its own before it becomes permanent: convert each numeral back to a number and check that day ≤ 31, month ≤ 12, and the year reads as expected. Never run the parts together — XIVIIMMXXVI is unreadable and unverifiable.

Numbers Above 3999: The Vinculum

Standard numerals stop at 3,999 (MMMCMXCIX) because M may repeat only three times. For larger values, a horizontal bar — the vinculum — over a numeral multiplies it by 1,000: V̄ = 5,000, X̄ = 10,000, M̄ = 1,000,000. In plain text where a bar cannot be drawn, parentheses are the usual substitute: (V) for 5,000.

Why Clocks Say IIII Instead of IV

Many clock and watch faces write 4 as IIII — a tradition, not a mistake. It balances visually with VIII on the opposite side of the dial, and the first four hours then use only I's. The Romans themselves used IIII more often than IV; the subtractive form only became standard in Europe after the printing press. Modern writing uses IV.

Where Roman Numerals Still Appear

• Monarchs and popes: Charles III, Elizabeth II, Pope Leo XIV.
• Sport: the NFL numbers Super Bowls in Roman numerals (the February 2026 game was Super Bowl LX); the Paris 2024 Olympics were the Games of the XXXIII Olympiad.
• Publishing: lowercase numerals (i, ii, iii, iv) number a book's front matter — preface, table of contents — so page 1 starts with chapter one.
• Film credits: copyright years were long printed in Roman numerals (MCMXCIV = 1994).
• Chemistry and music: oxidation states (iron(III) oxide) and chord analysis (I, IV, V).

What is the shortcut for years like 2026? Every year from 2000 to 2099 starts with MM, so only the last two digits need converting: 2026 → MM + XXVI = MMXXVI.

Can I write 49 as IL? No — I may only be subtracted from V and X. 49 is XL (40) + IX (9) = XLIX, as shown in Example 1 above.

How do I make sure a tattoo numeral is correct? Convert it back with this tool, check each date part separately (day ≤ 31, month ≤ 12), and have a second person verify it. Numerals are permanent; checking them twice is not.