Convert numbers to Roman numerals and Roman numerals back to numbers. Standard form, vinculum notation for large numbers, copy-ready output. Free.
A Roman numeral converter translates between Arabic numbers (the everyday 1, 2, 3 ...) and Roman numerals (I, II, III, IV, V, ...). Roman numerals are still used everywhere — movie copyright dates (MMXXIV), Super Bowl numbering (LVIII), chapter headings (Chapter IV), monarch names (Elizabeth II), and watch dials — so being able to convert quickly is more useful than you'd think.
This tool handles the full range from 1 to 3,999 in standard form and up to 3,999,999 using the vinculum (overline) notation for thousands and millions.
Type a number to see it as a Roman numeral, or type a Roman numeral (mixed case is fine) to see its Arabic value. Both directions work live — no submit button. The tool validates input and points out common errors (invalid subtractive sequences like IIII for 4 or VL for 45).
I — 1
V — 5
X — 10
L — 50
C — 100
D — 500
M — 1,000
V̄ (V with vinculum) — 5,000
X̄ — 10,000
L̄ — 50,000
C̄ — 100,000
D̄ — 500,000
M̄ — 1,000,000
1 = I 2 = II 3 = III 4 = IV 5 = V
6 = VI 7 = VII 8 = VIII 9 = IX 10 = X
40 = XL 50 = L 90 = XC 100 = C
400 = CD 500 = D 900 = CM 1000 = M
2026 = MMXXVI 2000 = MM 1999 = MCMXCIX
Bidirectional — number → Roman and Roman → number, in the same UI
Handles 1 to 3,999 in standard form; 4,000 to 3,999,999 with vinculum (overline) notation
Mixed-case input accepted (mcmxcix = MCMXCIX = 1999)
Validates Roman input — clearly flags invalid forms like IIII, VV, or IC
"Step-by-step" toggle shows how the conversion was built (useful for students)
One-click copy in either direction
Works offline once loaded
Dark mode that follows your system preference
Type a number into the top field (e.g. 2026).
The Roman numeral appears live in the bottom field (e.g. MMXXVI).
Or type a Roman numeral into the bottom field — the Arabic value appears above.
Toggle Show steps to see the decomposition.
Click Copy on either field to copy the value.
Where Roman numerals still come up:
Movie & TV credits — copyright dates like MMXXIV are standard.
Super Bowl & Olympic numbering — Super Bowl LVIII, Tokyo XXXII Olympiad.
Watch & clock dials — verifying what number a Roman-numeral watch face is showing.
Book chapter & section numbering — "Chapter IV", "Volume III" in academic and legal texts.
Monarch & pope names — Elizabeth II, Louis XIV, Pope John Paul II.
Outline notation — the classic I. A. 1. a. structure for essay outlines.
Tattoos & jewellery — converting a birth year or anniversary date into Roman numerals for engraving.
School & math homework — teaching subtractive notation, place value, and number-system history.
Quiz & trivia preparation — quickly verifying answers to Roman-numeral questions.
The output uses subtractive notation correctly (IV not IIII, IX not VIIII, XL not XXXX, CM not DCCCC) per the modern convention. Both standard form (1–3,999) and vinculum form (above 3,999) are supported.
Toggle "Show steps" to see how 1999 is built as M + CM + XC + IX. Great for students learning the numeral system or anyone curious about the conversion process.
Conversion runs entirely in your browser. No numbers, no Roman input, no usage data is sent anywhere.
No signup, no caps, no ads in your output. Open, type, copy.
IV instead of IIII?Modern Roman numerals use subtractive notation: when a smaller numeral precedes a larger one, you subtract. So IV = 5 − 1 = 4. Historically IIII was also used (and still appears on some traditional clock faces and watches like Rolex), but standard form is IV.
1999 = 1000 + 900 + 90 + 9 = M + CM + XC + IX = MCMXCIX. Each century, decade, and unit needs its own subtractive form. Years ending in 8 or 9 always look longer than they "should".
In standard form (without vinculum): 3,999 = MMMCMXCIX. With vinculum (overlines indicating ×1000): 3,999,999. Beyond that, you'd need additional bar notation that isn't standardised.
You don't — the Roman system has no symbol for zero. The concept of zero arrived in Europe long after the Roman numeral system was established. Medieval mathematicians sometimes used N (from Latin nulla) as a placeholder, but it isn't a standard Roman numeral.
A horizontal bar drawn above a Roman numeral to multiply its value by 1,000. V̄ = 5,000, X̄ = 10,000, and so on. Originally used by Romans for large numbers in census and military records.
MMXXVI — that's MM (2000) + XX (20) + VI (6). Useful for movie credits, copyright lines, and the next decade's anniversary engravings.
Yes. Lowercase forms (i, v, x, l, c, d, m) have the same meaning and are common in outline notation (e.g. sub-points i, ii, iii within an outline). Our converter accepts both cases.
Yes — conversion runs entirely client-side. Once the page loads, no network is required.
How to Use Roman Numeral Converter — Numbers to Roman & Back (1 to 3,999,999)
Enter or paste the content you want to process using the roman numeral converter — numbers to roman & back (1 to 3,999,999).
Adjust any available settings or options to customize the output.
View, copy, or download your processed results instantly.
Convert numbers to Roman numerals and Roman numerals back to numbers. Standard form, vinculum notation for large numbers, copy-ready output. Free.
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