- Communication System
- Numeral System
- Roman Numerals
Roman Numerals to Hindu-Arabic (English) Converter
Roman Numeral Writer
Answers to Questions (FAQ)
What are Roman Numerals? (Definition)
Roman numerals are the name given to the numeral system used in ancient Roman times (especially in the time of Caesar), read from left to right it uses 7 letters whose values are added or subtracted according to their position.
What are the letters to write in Roman Numerals?
Roman numeration uses 7 letters corresponding to 7 numbers. Roman digits chart from 1 to 1000:
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
Beyond several thousands, there are no letters to represent these numbers.
However, some archaic scripts (more rare) used 4 other symbols
| Ɔ | 500 |
| ↀ | 1000 |
| ↁ | 5000 |
| ↂ | 10000 |
How to read/write with Roman numerals?
Roman numeral system uses two rules:
— (1) Any letter $ L_2 $ placed to the right of another letter $ L_1 $ are added if $ L_2 \leq L_1 $
Example: VI = 5 + 1 = 6
XX = 10 + 10 = 20
— (2) Any letter of unit $ L_1 = \rm{I} $ placed immediately to the left of another letter $ L_2 \neq \rm{I} $ is subtracted.
Example: IV = 5 - 1 = 4
IX = 10 - 1 = 9
IL = 50 - 1 = 49
IC = 100 - 1 = 99
ID = 500 - 1 = 499
Rule (2) is sometimes extended to: Any letter $ L_1 $ placed immediately to the left of another letter $ L_2 > L_1 $ is subtracted.
Example: XC = 100 - 10 = 90
In theory therefore, any symbol (letter) is repeated a maximum of 3 times consecutively.
Example:
| 1970 in roman numerals | MCMLXX | 1971 in roman numerals | MCMLXXI |
|---|---|---|---|
| 1972 in roman numerals | MCMLXXII | 1973 in roman numerals | MCMLXXIII |
| 1974 in roman numerals | MCMLXXIV | 1975 in roman numerals | MCMLXXV |
| 1976 in roman numerals | MCMLXXVI | 1977 in roman numerals | MCMLXXVII |
| 1978 in roman numerals | MCMLXXVIII | 1979 in roman numerals | MCMLXXIX |
| 1980 in roman numerals | MCMLXXX | 1981 in roman numerals | MCMLXXXI |
| 1982 in roman numerals | MCMLXXXII | 1983 in roman numerals | MCMLXXXIII |
| 1984 in roman numerals | MCMLXXXIV | 1985 in roman numerals | MCMLXXXV |
| 1986 in roman numerals | MCMLXXXVI | 1987 in roman numerals | MCMLXXXVII |
| 1988 in roman numerals | MCMLXXXVIII | 1989 in roman numerals | MCMLXXXIX |
| 1990 in roman numerals | MCMXC | 1991 in roman numerals | MCMXCI |
| 1992 in roman numerals | MCMXCII | 1993 in roman numerals | MCMXCIII |
| 1994 in roman numerals | MCMXCIV | 1995 in roman numerals | MCMXCV |
| 1996 in roman numerals | MCMXCVI | 1997 in roman numerals | MCMXCVII |
| 1998 in roman numerals | MCMXCVIII | 1999 in roman numerals | MCMXCIX |
| 2000 in roman numerals | MM | 2001 in roman numerals | MMI |
| 2002 in roman numerals | MMII | 2003 in roman numerals | MMIII |
| 2004 in roman numerals | MMIV | 2005 in roman numerals | MMV |
| 2006 in roman numerals | MMVI | 2007 in roman numerals | MMVII |
| 2008 in roman numerals | MMVIII | 2009 in roman numerals | MMIX |
| 2010 in roman numerals | MMX | 2011 in roman numerals | MMXI |
| 2012 in roman numerals | MMXII | 2013 in roman numerals | MMXIII |
| 2014 in roman numerals | MMXIV | 2015 in roman numerals | MMXV |
| 2016 in roman numerals | MMXVI | 2017 in roman numerals | MMXVII |
| 2018 in roman numerals | MMXVIII | 2019 in roman numerals | MMXIX |
| 2020 in roman numerals | MMXX | 2021 in roman numerals | MMXXI |
| 2022 in roman numerals | MMXXII | 2023 in roman numerals | MMXXIII |
| 2024 in roman numerals | MMXXIV | 2025 in roman numerals | MMXXV |
How does the converter from/to Roman numerals work?
The program automatically detects whether the number is in Arabic or Roman numerals and makes the conversion/translation.
Roman numeration does not permit writing large numbers, beyond 9999 the program will display the number of thousands separately. This writing is not standardized but remains comprehensible.
The program is very permissive and allows badly formed Roman numbers not complying with the rule (2).
Example: IVX is translated as 6
How to write zero (0) in Roman numerals?
Romans did not use the zero, for them it was not a digit but a state of emptiness, so they did not write it (the absence of a number indicates zero).
dCode writes either ??, or 0.
How to write four (4) in Roman numerals?
Four is written IV, however, this software indicates that IIII = 4, unusual, IIII is a variant of IV which is tolerated. It can be found today (typically in watches, or clocks).
How to write a date with roman numerals?
There is no specific way to write a date (or a birthdate), except to write the number of the day, the month and the year separately.
Example: 12 / 06 / 2008 = XII / VI / MMVIII
dCode has a tool to write a date in latin.
In some European countries, the centuries are sometimes written in Roman numerals.
What is the biggest number in roman numerals?
Numbers above 10000 were not thinkable, without any calculation tool, they were useless. If you wish to write a value of hundreds of thousands, one can imagine writing hundreds of M at the beginning of the number.
Example: 9999 = MMMMMMMMMCMXCIX (a bit ridiculous)
How to write negative numbers in roman numerals?
The negative writing is not recognized, it probably did not exist. The notion of positive or negative numbers is related to the concept of zero (which was not known to the Romans).
However, today, adding a - can help to be understood.
Example: -XXV = -25
How to write a decimal number in roman numerals?
Using decimal numbers is very few documented in history books, however, it is probable that they used fractions, including a duodecimal currency system (base 12) which allowed sharing by 2, 3, 4, 6 and 12 without decimal places.
When were Roman Numerals invented?
Roman numerals were born with Antique Rome, so starting at the 7th century BC. For example, they were used with Latin.
How to write Roman Numerals with Unicode?
Roman numerals have been added to the Unicode standard, they encode by a single character each number from 1 to 12 (used in clocks and watches) and 8 other numbers meaning:
| Unicode character | Value | Unicode character | Value | Unicode character | Value |
|---|---|---|---|---|---|
| Ⅰ | 1 | Ⅱ | 2 | Ⅲ | 3 |
| Ⅳ | 4 | Ⅴ | 5 | Ⅵ | 6 |
| Ⅶ | 7 | Ⅷ | 8 | Ⅸ | 9 |
| Ⅹ | 10 | Ⅺ | 11 | Ⅻ | 12 |
| Ⅼ | 50 | Ⅽ | 100 | Ɔ | 500 |
| Ⅾ | 500 | ↀ | 1000 | Ⅿ | 1000 |
| ↁ | 5000 | ↂ | 10000 |
Can there be more than 4 identical consecutive letters?
Roman numerals can be written with 4 identical letters in a row, but this is rare or incorrect.
Example: 4000 can be written MMMM or the watchmaker's four is written IIII
When to use Roman Numerals?
Roman numerals are learned at school in primary school but are rarely used except in mathematics or history. The uses today are limited to clocks, dates, but also on tattoos, many tattoos use Roman numerals.
Source code
dCode retains ownership of the "Roman Numerals" source code. Except explicit open source licence (indicated Creative Commons / free), the "Roman Numerals" algorithm, the applet or snippet (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, breaker, translator), or the "Roman Numerals" functions (calculate, convert, solve, decrypt / encrypt, decipher / cipher, decode / encode, translate) written in any informatic language (Python, Java, PHP, C#, Javascript, Matlab, etc.) and all data download, script, or API access for "Roman Numerals" are not public, same for offline use on PC, mobile, tablet, iPhone or Android app!
Reminder : dCode is free to use.
Cite dCode
The copy-paste of the page "Roman Numerals" or any of its results, is allowed (even for commercial purposes) as long as you credit dCode!
Exporting results as a .csv or .txt file is free by clicking on the export icon
Cite as source (bibliography):
Roman Numerals on dCode.fr [online website], retrieved on 2024-07-15,
