A Complete Guide to Roman Numerals
March 30, 2026
What Are Roman Numerals?
Roman numerals are a number system from ancient Rome that uses combinations of seven Latin letters to represent values. Unlike our modern system (0-9 with place value), Roman numerals use additive and subtractive rules to build numbers from these symbols.
They were the standard across Europe for over a thousand years. Today they're decorative rather than functional, but they still show up everywhere — and understanding them takes about five minutes.
The Seven Symbols
| Symbol | Value | Origin |
|---|---|---|
| I | 1 | A single tally mark — one finger held up |
| V | 5 | An open hand, all five fingers spread |
| X | 10 | Two hands crossed (or two V shapes joined) |
| L | 50 | Evolved from an Etruscan symbol, reshaped into a Latin letter |
| C | 100 | From centum (Latin for hundred) |
| D | 500 | Half of the ancient symbol for 1,000 |
| M | 1,000 | From mille (Latin for thousand) |
These seven symbols can represent any number from 1 to 3,999 in standard notation.
The Four Rules
1. Addition: bigger comes first
When symbols go from large to small (left to right), you add them up:
- VI = 5 + 1 = 6
- LXIII = 50 + 10 + 1 + 1 + 1 = 63
- MDCLXVI = 1000 + 500 + 100 + 50 + 10 + 5 + 1 = 1,666
2. Subtraction: smaller before bigger
When a smaller symbol appears directly before a larger one, subtract it:
- IV = 5 − 1 = 4
- IX = 10 − 1 = 9
- XL = 50 − 10 = 40
- XC = 100 − 10 = 90
- CD = 500 − 100 = 400
- CM = 1000 − 100 = 900
Only these six subtractive pairs are valid. You can't write things like IC (99) or XM (990).
3. Maximum three in a row
You can repeat I, X, C, and M up to three times. Never four. That's why 4 is IV (not IIII) and 40 is XL (not XXXX).
V, L, and D are never repeated — doubling them would just equal the next symbol up (VV = X).
4. Read left to right
Process the numeral from left to right, applying addition and subtraction as you go. When you spot a smaller value before a larger one, subtract. Otherwise, add.
Converting Numbers to Roman Numerals
Break the number down by place value, convert each part, then concatenate:
Example: 1,994
| Place | Value | Roman |
|---|---|---|
| Thousands | 1,000 | M |
| Hundreds | 900 | CM |
| Tens | 90 | XC |
| Ones | 4 | IV |
Result: MCMXCIV
Example: 2,026
| Place | Value | Roman |
|---|---|---|
| Thousands | 2,000 | MM |
| Tens | 20 | XX |
| Ones | 6 | VI |
Result: MMXXVI
Quick Reference: All Place Values
| Ones | Tens | Hundreds | Thousands |
|---|---|---|---|
| 1 = I | 10 = X | 100 = C | 1,000 = M |
| 2 = II | 20 = XX | 200 = CC | 2,000 = MM |
| 3 = III | 30 = XXX | 300 = CCC | 3,000 = MMM |
| 4 = IV | 40 = XL | 400 = CD | |
| 5 = V | 50 = L | 500 = D | |
| 6 = VI | 60 = LX | 600 = DC | |
| 7 = VII | 70 = LXX | 700 = DCC | |
| 8 = VIII | 80 = LXXX | 800 = DCCC | |
| 9 = IX | 90 = XC | 900 = CM |
Converting Roman Numerals to Numbers
Read left to right. If a symbol is smaller than the one after it, subtract. Otherwise, add.
Example: MCMXLIV
- M = 1,000 (add)
- CM = 900 (C before M, subtract)
- XL = 40 (X before L, subtract)
- IV = 4 (I before V, subtract)
- Total: 1,944
Chart: 1 to 100
| 1 = I | 11 = XI | 21 = XXI | 31 = XXXI | 41 = XLI |
| 2 = II | 12 = XII | 22 = XXII | 32 = XXXII | 42 = XLII |
| 3 = III | 13 = XIII | 23 = XXIII | 33 = XXXIII | 43 = XLIII |
| 4 = IV | 14 = XIV | 24 = XXIV | 34 = XXXIV | 44 = XLIV |
| 5 = V | 15 = XV | 25 = XXV | 35 = XXXV | 45 = XLV |
| 6 = VI | 16 = XVI | 26 = XXVI | 36 = XXXVI | 46 = XLVI |
| 7 = VII | 17 = XVII | 27 = XXVII | 37 = XXXVII | 47 = XLVII |
| 8 = VIII | 18 = XVIII | 28 = XXVIII | 38 = XXXVIII | 48 = XLVIII |
| 9 = IX | 19 = XIX | 29 = XXIX | 39 = XXXIX | 49 = XLIX |
| 10 = X | 20 = XX | 30 = XXX | 40 = XL | 50 = L |
| 51 = LI | 61 = LXI | 71 = LXXI | 81 = LXXXI | 91 = XCI |
| 52 = LII | 62 = LXII | 72 = LXXII | 82 = LXXXII | 92 = XCII |
| 53 = LIII | 63 = LXIII | 73 = LXXIII | 83 = LXXXIII | 93 = XCIII |
| 54 = LIV | 64 = LXIV | 74 = LXXIV | 84 = LXXXIV | 94 = XCIV |
| 55 = LV | 65 = LXV | 75 = LXXV | 85 = LXXXV | 95 = XCV |
| 56 = LVI | 66 = LXVI | 76 = LXXVI | 86 = LXXXVI | 96 = XCVI |
| 57 = LVII | 67 = LXVII | 77 = LXXVII | 87 = LXXXVII | 97 = XCVII |
| 58 = LVIII | 68 = LXVIII | 78 = LXXVIII | 88 = LXXXVIII | 98 = XCVIII |
| 59 = LIX | 69 = LXIX | 79 = LXXIX | 89 = LXXXIX | 99 = XCIX |
| 60 = LX | 70 = LXX | 80 = LXXX | 90 = XC | 100 = C |
Key Milestone Numbers
| Number | Roman | Why It Matters |
|---|---|---|
| 4 | IV | First use of the subtraction rule |
| 9 | IX | Subtractive pair with X |
| 49 | XLIX | Not IL — a common mistake |
| 99 | XCIX | Not IC — another common mistake |
| 400 | CD | C subtracted from D |
| 999 | CMXCIX | Not IM — all three subtractive tiers |
| 1,666 | MDCLXVI | Uses every symbol exactly once, in order |
| 3,888 | MMMDCCCLXXXVIII | Longest Roman numeral under 4,000 (15 chars) |
| 3,999 | MMMCMXCIX | Highest standard Roman numeral |
Numbers Above 3,999
Standard Roman numerals max out at 3,999 (MMMCMXCIX). For larger numbers, the Romans used the vinculum: a line above a numeral that multiplies its value by 1,000.
| Symbol | Value |
|---|---|
| V | 5,000 |
| X | 10,000 |
| L | 50,000 |
| C | 100,000 |
| M | 1,000,000 |
A double overline multiplies by 1,000,000. In practice, numbers this large were rarely written in Roman times — they used words instead.
Common Mistakes
- IL for 49 — wrong. Only I before V and X is valid. Correct: XLIX.
- IC for 99 — wrong. Correct: XCIX.
- IIII for 4 — technically non-standard, but accepted on clock faces.
- VV for 10 — never. V is not repeated. Use X.
- Mixing cases — Roman numerals are always uppercase. "xvii" is informal at best.
Where You'll See Them Today
- Clock faces — the most common everyday encounter
- Super Bowl — every year since V (1971), except 50
- Movie credits — copyright years at the end of films
- Sequels — Rocky II, Star Wars IV, Final Fantasy XVI
- Monarchs & popes — Elizabeth II, Benedict XVI
- Building cornerstones — construction years carved in stone
- Tattoos — dates and significant numbers
- Outlines — I, II, III as section markers
- Chemistry — oxidation states (FeIII)
More Articles
- Why Are Roman Numerals Still Popular in the 21st Century?
From clock faces to tattoos to Super Bowl logos: why a 2,000-year-old number system refuses to die in the age of smartphones.
- Super Bowl & Roman Numerals: Gladiators, Marketing, and the Letter L
Why the NFL numbers its biggest game like a Roman gladiator match. The one year they stopped, and what Super Bowl XIII tells us about superstition.
- The Case for Roman Numerals in the 21st Century
Roman numerals are terrible for math. But for hierarchy, permanence, and visual distinction, they might be the best tool we have.
- Why the World Uses 1, 2, 3 Instead of I, II, III
How Hindu-Arabic numerals replaced Roman numerals, why Florence banned the new numbers, and what Fibonacci had to do with it.
- The History of Roman Numerals: They Are Not Actually Roman
From Etruscan tally marks to empire-wide accounting to decorative art. How seven impractical letters outlived the civilization that made them famous.
- How Do Roman Numerals Work? A Complete Guide
Learn how the Roman numeral system works, from basic symbols to complex conversions. Complete guide with examples, rules, and history.
- Roman Numeral Tattoo Ideas: Dates, Numbers & Design Inspiration
Find the perfect Roman numeral tattoo design. Convert dates to Roman numerals, explore placement ideas, font styles, and avoid common mistakes.
- Super Bowl Roman Numerals: Complete List From I to Today
Complete list of every Super Bowl in Roman numerals from I to today. Learn why the NFL uses Roman numerals and the one time they didn't.
- Why Do Clocks Use IIII Instead of IV?
Discover why most clock faces display IIII instead of IV for the number 4. Explore the theories behind this centuries-old clockmaking tradition.
- Roman Numerals Chart: 1 to 1000 Complete Reference
Complete Roman numerals chart from 1 to 1000. Printable reference tables for 1-20, tens, hundreds, and key milestone numbers.
- Roman Numerals in Movies, Games & Pop Culture
Why movie sequels and video games use Roman numerals. Famous examples from Star Wars to Final Fantasy, and the tradition of copyright years in credits.
- The History of Roman Numerals: From Ancient Rome to Today
Trace the full history of Roman numerals from Etruscan tally marks through the Roman Empire to their survival in modern usage.