The Super Bowl is never number 60. It is Super Bowl LX, because the NFL numbers its championship game in Roman numerals, and LX is 50 plus 10. The system is beautifully economical: seven letters do all the work, and a subtraction trick handles the rest. Once you learn those seven letters and the six subtraction pairs, you can read a cornerstone date, a film copyright line, a monarch's name, or a tattoo year without reaching for a chart, and you can spot the common errors that make a tattoo or an engraving permanently wrong.

The seven symbols and the additive rule

The seven symbols are I equals 1, V equals 5, X equals 10, L equals 50, C equals 100, D equals 500, and M equals 1000. Most of the time the rule is simply addition from left to right, with symbols arranged from largest to smallest. VI is 5 plus 1, which is 6. XII is 10 plus 1 plus 1, which is 12. XXVII is 10 plus 10 plus 5 plus 1 plus 1, which is 27. CLX is 100 plus 50 plus 10, which is 160. MD is 1000 plus 500, which is 1500. Read left to right, add as you go, and most numerals surrender immediately. The trouble starts only at the numbers that would otherwise need four identical symbols in a row, and that is where the second rule enters.

The subtraction rule: six pairs, no more

When a smaller symbol appears immediately before a larger one, it subtracts instead of adding. Only six such pairs are valid: IV is 5 minus 1, which is 4; IX is 10 minus 1, which is 9; XL is 50 minus 10, which is 40; XC is 100 minus 10, which is 90; CD is 500 minus 100, which is 400; and CM is 1000 minus 100, which is 900. That short list is the whole subtraction system, and its limits matter as much as the pairs themselves. Only I, X, and C can ever be the subtracting symbol, and each subtracts only from the next two larger values: I from V and X, X from L and C, C from D and M. That is why 49 is XLIX, 40 plus 9, and never IL, and why 99 is XCIX, 90 plus 9, and never IC. A pair like VX or LC is not a clever shortcut; it is simply not a Roman numeral at all.

The repetition rules that force subtraction into existence

I, X, C, and M may each repeat up to three times in a row, and no more: III is 3, XXX is 30, CCC is 300, MMM is 3000. V, L, and D are never repeated, because two of them would equal the next symbol up: VV would be 10, which is already X, and LL would be 100, which is already C. The subtraction rule exists to stop the repetition rule from breaking: 4 cannot be IIII under standard rules, so it becomes IV, and 9 cannot be VIIII, so it becomes IX. Clock faces are the famous exception, and they break the rule on purpose: many traditional clock dials show IIII for 4 instead of IV, a choice usually credited to visual balance against VIII on the opposite side of the dial, or to old dial-making habit. A clock face is not wrong; it is following a separate tradition. Everywhere else, IIII is a mistake, and it is the first mistake a tattoo artist should catch.

The place-value method this converter uses

The cleanest way to convert a number is to split it into thousands, hundreds, tens, and ones, convert each place separately, and join the pieces. This converter does exactly that split for you: type a number in the Arabic Number box and read the Thousands digit, Hundreds digit, Tens digit, and Ones digit outputs. The year 2024 splits into 2 thousands, 0 hundreds, 2 tens, and 4 ones, which assemble into MM plus nothing plus XX plus IV, giving MMXXIV. The number 42 splits into 0 thousands, 0 hundreds, 4 tens, and 2 ones, giving XL plus II, which is XLII. The year 1999, the trickiest year of the bunch, splits into 1 thousand, 9 hundreds, 9 tens, and 9 ones, giving M plus CM plus XC plus IX, which is MCMXCIX, with the subtraction rule applied three times in a single number. Work place by place and no number can surprise you, because each place has only ten possible forms, and six of them use subtraction.

The greedy method: largest value first

A second method works just as well and is worth knowing because it explains how converters think. Start with the largest value that fits, write its symbol, subtract, and repeat. Take 1987. The largest value that fits is 1000, M, leaving 987. Next 900 fits as CM, leaving 87. Then 50 fits as L, leaving 37. Then 10 fits three times as XXX, leaving 7. Then 5 fits as V, leaving 2, and 1 fits twice as II. Join them: M plus CM plus LXXX plus VII gives MCMLXXXVII. Take 2468 the same way: 2000 gives MM, 400 gives CD, 60 gives LX, 8 gives VIII, and the answer is MMCDLXVIII. Take 3888, the largest number that uses every symbol in descending order: 3000 gives MMM, 800 gives DCCC, 80 gives LXXX, 8 gives VIII, and the answer is MMMDCCCLXXXVIII. The greedy method never fails, because the value list it walks down already contains the six subtraction pairs alongside the seven symbols.

Reading a numeral back: scan and compare

Going the other direction, scan the symbols left to right and compare each symbol with the one after it. If a symbol is smaller than the next one, subtract it; otherwise add it. Read MMXXVI: M adds 1000, M adds 1000, X adds 10, X adds 10, V adds 5, I adds 1, and the total is 2026. Read MDCCLXXVI: M adds 1000, D adds 500, C adds 100, C adds 100, L adds 50, X adds 10, X adds 10, V adds 5, I adds 1, and the total is 1776, the year of American independence. Read MDCLXVI: 1000 plus 500 plus 100 plus 50 plus 10 plus 5 plus 1 is 1666, a curiosity because its symbols run in perfect descending order, each symbol used exactly once. The scan-and-compare rule also catches bad input: if you ever need to subtract the same symbol twice, or subtract across two steps, the numeral is malformed, which is how you know MIM is not 1999 and IL is not 49.

The ones, tens, hundreds, and thousands ladders

Each decimal place has its own short ladder, and memorizing the shape of one ladder teaches you all four, because the pattern repeats with different symbols. The ones ladder is I, II, III, IV, V, VI, VII, VIII, IX. The tens ladder is X, XX, XXX, XL, L, LX, LXX, LXXX, XC. The hundreds ladder is C, CC, CCC, CD, D, DC, DCC, DCCC, CM. The thousands ladder is simply M, MM, MMM, and then the system stops. Spot values along these ladders are worth knowing by heart: 44 is XLIV, 40 plus 4; 99 is XCIX, 90 plus 9; 444 is CDXLIV, 400 plus 40 plus 4; 949 is CMXLIX, 900 plus 40 plus 9. Notice how each spot value applies the subtraction rule once per place, never twice in one place, and never across places. A numeral that breaks that rhythm is worth re-reading before it goes on skin or stone.

Years people actually look up

Most Roman numeral searches are years, so the recent run is worth fixing in memory. The year 2024 is MMXXIV. The year 2025 is MMXXV. The year 2026 is MMXXVI. The year 2027 is MMXXVII. The year 2000 is MM, and 1900 is MCM. The year 1800 is MDCCC, 1000 plus 500 plus 300. The year 1500 is MD, and 1000 is M, and 500 is D. Birth years and anniversary years dominate tattoo requests, and they are where the expensive mistakes happen: a birth year of 1999 must be MCMXCIX, not the tempting MIM, and a birth year of 1987 must be MCMLXXXVII, with the CM and the LXXX both present. Before any permanent use, convert the year by the place-value method, read it back by scan-and-compare, and check it against the digit breakdown this converter shows. Three checks take a minute; a wrong tattoo lasts a lifetime.

Why the system stops at 3999, and the zero problem

The largest number standard Roman numerals can write is 3999, which is MMMCMXCIX: 3000 plus 900 plus 90 plus 9. The ceiling comes from the repetition rule: M can appear at most three times, giving 3000, and the remaining places max out at 999, which is CMXCIX. There is no standard single symbol for 5000 in everyday notation. Extended systems draw a horizontal bar over a symbol, called a vinculum, to multiply it by 1000, so a barred V means 5000, but plain text cannot show the bar reliably, and this converter correctly stays within 1 to 3999. A second gap is zero: the Romans had no symbol for zero at all, and no place-value system to need one. The word nulla, meaning none, was used in writing much later, but there is no Roman zero to convert to, and any converter that claims otherwise is inventing history.

Where Roman numerals still live

Super Bowl numbers are the most visible modern use: Super Bowl LX is number 60, L plus X, and the league has used the system since the first championship game. Monarchs and popes carry them as regnal numbers: Elizabeth II is the second of her name, and Henry VIII is the eighth. Film and television credits date productions this way, which is why MCMXCIX turns up at the end of older movies. Book chapters, outlines, and appendices use them for major divisions, and clock faces, cornerstones, building dedications, memorial plaques, and tattoos keep them in daily sight. Sporting events, pageants, and anniversary celebrations borrow the same classical weight. In each case the appeal is the same: the numeral looks timeless because the system itself is ancient, and it reads as a label rather than a quantity, which is exactly what a championship, a reign, or a dedication wants.

Six mistakes that ruin a conversion

The first mistake is writing IL for 49 or IC for 99: only the six pairs subtract, and 49 is XLIX while 99 is XCIX. The second is writing MIM for 1999: subtraction applies once per place, so 1999 is MCMXCIX, with CM, XC, and IX each doing one job. The third is repeating V, L, or D, as in VV for 10 or LL for 100, when X and C already exist. The fourth is repeating a symbol four times in standard notation, IIII for 4 outside a clock face, or XXXX for 40. The fifth is reading without the subtraction step, turning IV into 6 by adding 1 and 5, or IX into 11. The sixth is forgetting the range: entering 0, a negative number, or anything above 3999 and expecting a standard numeral, when the system has no zero and no symbol beyond M. Every one of these mistakes is caught by the same habit: convert place by place, read back by scan-and-compare, and trust the digit breakdown over your first guess.

How to use this converter, honestly

This converter breaks a number into its place values rather than printing the assembled numeral as a single string. Type any whole number from 1 to 3999 in the Arabic Number box, for example 2024, and read the four outputs: Thousands digit 2, Hundreds digit 0, Tens digit 2, and Ones digit 4, and the assembled numeral is MMXXIV. Try 1999 to see the subtraction rule at work across all three lower places: the breakdown is 1 thousand, 9 hundreds, 9 tens, and 9 ones, leading to MCMXCIX. Try 42 to see the zero places: 0 thousands, 0 hundreds, 4 tens, and 2 ones assemble into XLII. The tool gives you the exact digit breakdown; the assembly step, joining the four place forms, is a short hand step described above, and keeping it visible is what stops the classic MIM and IL errors. Stay within 1 to 3999, because the classical system has no standard symbols beyond that range.

Related calculators on this site

If the Roman numeral is part of a bigger date or number job, companion tools carry the next step. The date to Roman converter turns a full Gregorian date, day, month, and year, into classical Roman numerals, which is the tool you want for a complete birth date rather than a single year. The decimal to binary converter and the binary to decimal converter cover the modern number systems that replaced Roman numerals for computation, and the decimal to hexadecimal converter covers the base-16 system used across computing. Comparing the systems is instructive: binary and hexadecimal are place-value systems with a zero, which is exactly the machinery Roman numerals never had, and that missing zero is why Roman arithmetic stayed hard while modern arithmetic became easy.

A short history note on why the system looks the way it does

Roman numerals grew out of tally marks, which is why I, II, and III look like counting strokes, and why V may come from a hand shape and X from two hands crossed. The subtractive shorthand arrived later and was not always applied consistently in ancient inscriptions, which is why archaeologists find IIII and other non-standard forms carved in stone. The strict modern rules, six subtraction pairs, three-repeat maximum, no repeated V, L, or D, are a later standardization, settled long after the empire fell, and they are the rules this page teaches. Knowing that the rules were standardized late explains both the clock-face exception and the occasional ancient oddity: the system you learn today is the cleaned-up version, and it is the version every modern reader expects.

With the pre-filled defaults — Arabic Number 2,024 — the Roman Numeral Converter returns Thousands digit (M) 2, Hundreds digit 0, Tens digit 2, Ones digit 4. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.