CalcOpenly
Français

Convertisseur de chiffres romains

Convertissez des nombres en chiffres romains et inversement, de 1 à 3,999 (jusqu’à 3,999,999 avec des barres suscrites), et retrouvez leur forme standard.

Mis à jour Exemples vérifiés : 8

1 to 3999; up to 3,999,999 with the overline option.
Plus d’options
Essayer
Résultat
MMXXVI
Résultat: MMXXVI
Valeur
2,026

2,026 is MMXXVI: MM = 2,000, XX = 20, VI = 6.

MMXXVI by place value

MM2,000XX20VI6
Comment le calcul est effectué S

  1. Split into place values

    2026=2000+20+62026 = 2000 + 20 + 6

  2. Write each place value

    2000→MM,20→XX,6→VI2000 \to \text{MM},\quad 20 \to \text{XX},\quad 6 \to \text{VI}

    4s and 9s use subtraction: IV, IX, XL, XC, CD, CM.

  3. Join the symbols

    2026=MMXXVI2026 = \text{MMXXVI}

À propos de Convertisseur de chiffres romains

Roman numerals write numbers with seven letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1000. To convert a number, the converter splits it into thousands, hundreds, tens and ones and writes each place separately; a 4 or 9 puts a smaller letter before a larger one, so 40 is XL and 900 is CM. To read a numeral, it adds the letters from left to right and subtracts any letter that stands before a larger one.

The default, 2026, splits into 2000 + 20 + 6 and becomes MMXXVI. The usual uses are years on buildings and in film credits, clock faces, chapter numbers and outlines. Reading MCMXCIV gives 1000 + 900 + 90 + 4 = 1994.

Standard numerals stop at 3999 (MMMCMXCIX). With the overline option a bar multiplies letters by 1000, so V̅ = 5000, up to 3,999,999. Non-standard numerals such as IIII or IC are still read, and the standard spelling is shown next to the value.

Exemples détaillés

2421

Conversions
Number to Roman
Number
2421
Résultat
MMCDXXI
Valeur
2,421

Source de vérification : Wikipedia — Roman numerals, standard-form examples (2421 = MMCDXXI); Python greedy conversion (forkA/verify_roman.py)

1776 (Statue of Liberty tablet)

Conversions
Number to Roman
Number
1776
Résultat
MDCCLXXVI

Source de vérification : Inscription JULY IV MDCCLXXVI on the Statue of Liberty's tablet; Python greedy conversion

3999, the largest standard numeral (edge)

Conversions
Number to Roman
Number
3999
Résultat
MMMCMXCIX

Source de vérification : Wikipedia — Roman numerals: MMMCMXCIX is the largest number in standard form; Excel ROMAN(3999)

XLII to a number

Conversions
Roman to number
Roman numeral
XLII
Résultat
42
Valeur
42
Standard Roman form
XLII

Source de vérification : XL = 40, II = 2; Python parser (forkA/verify_roman.py)

Questions

What is 2026 in Roman numerals?

MMXXVI: MM = 2000, XX = 20 and VI = 6. Years are converted one place at a time, so 1999 is MCMXCIX (1000 + 900 + 90 + 9) rather than MIM, and 2000 is simply MM. The same rule gives MDCCLXXVI for 1776, the year inscribed on the tablet held by the Statue of Liberty.

What is the largest Roman numeral?

In standard form the largest number is 3999, written MMMCMXCIX, because there is no letter for 5000 and a letter repeats at most three times. Excel's ROMAN function returns #VALUE! above 3999 for the same reason. Larger numbers used an overline (vinculum) that multiplies by 1000: V̅ is 5000 and I̅V̅ is 4000, which takes this converter up to 3,999,999.

Is 4 written IV or IIII?

IV is the standard form; IIII is the additive form, and both mean 4. Standard form uses only six subtractive pairs: IV, IX, XL, XC, CD and CM. Many clock faces still show IIII for four o'clock while using IX for nine, a practice that goes back to clocks such as the late 14th-century Wells Cathedral clock. The converter reads IIII as 4 and gives IV as the standard spelling.

Why is 99 written XCIX and not IC?

Standard form lets a letter be subtracted only from the next two larger letters: I from V and X, X from L and C, and C from D and M. So 99 is 90 + 9 = XC + IX = XCIX, and 49 is XLIX rather than IL. Excel's ROMAN function breaks the rule only on request: its form 4 writes 499 as ID, while the default form gives CDXCIX.

Is there a Roman numeral for zero?

No. The Roman system had no symbol for zero, so the converter starts at 1. Medieval scholars wrote the Latin word nulla ("none") instead: Dionysius Exiguus used it in 525, and around 725 Bede or a colleague abbreviated it to the letter N.

Quelle est la précision de « Convertisseur de chiffres romains » ?

La précision dépend de vos données et des hypothèses de la méthode. Le calcul décimal utilise 50 chiffres significatifs, mais les estimations, méthodes numériques et données sources peuvent être moins précises ; l’arrondi affiché ne supprime pas ces limites. Exemples résolus vérifiés à partir de sources indépendantes : 8. Par exemple, « 2421 » est vérifié à l’aide de Wikipedia — Roman numerals, standard-form examples (2421 = MMCDXXI); Python greedy conversion (forkA/verify_roman.py).

D’où vient cette méthode ?

Wikipedia — Roman numerals (standard form); Microsoft Excel ROMAN and ARABIC functions.

À propos de ce calculateur

I=1, V=5, X=10, L=50, C=100, D=500, M=1000a smaller symbol before a larger one is subtracted: IV=4, XC=90\begin{gathered}\text{I}=1,\ \text{V}=5,\ \text{X}=10,\ \text{L}=50,\ \text{C}=100,\ \text{D}=500,\ \text{M}=1000 \\ \text{a smaller symbol before a larger one is subtracted: IV} = 4,\ \text{XC} = 90\end{gathered}

Sources

  1. Wikipedia — Roman numerals (standard form)
  2. Microsoft Excel ROMAN and ARABIC functions

Vérifié avec les références

Ce calculateur comprend 8 exemples résolus dont les réponses proviennent de sources indépendantes. Ils font partie de la suite de tests et peuvent aussi être exécutés ici.

Calculatrices associées