Tiny tools - Roman numerals converter

Roman numeral converter

This is a roman numeral converter that can convert numbers between 1 and 20000 from the decimal system to roman system or from the roman system the decimal system. Enter a decimal number in the text box marked number or enter a roman numeral in the text box marked roman numeral and the conersion will happen automatic.
Roman numeral

About roman numerals

Roman numerals is numeral system that uses combinations of the latin letters I, V, X, L, C, D and M instead of Arabic numerals to signify values.

The letters have the following values:

I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1000

Numbers are formed by combining letters togehter and adding or subtracting there values. All values is added except when smaller values precede larger values, the smaller values are then subtracted from the larger values. Some examples:

VI = 5 + 1 = 6
IX = -1 + 10 = 9
MCMXLIV = 1000 -100 + 1000 - 10 + 50 - 1 + 5 = 1944

There are a few more rules that must be met for a Roman number to be valid. They are:

1. The letters I, X, C, and M can be repeated three times in succession, but no more. D, L, and V can never be repeated.

2. I can be subtracted from V and X only. X can be subtracted from L and C only. C can be subtracted from D and M only. V, L, and D can never be subtracted.

3. Only one small-value symbol may be subtracted from any large-value symbol.

4. A number written in Arabic numerals can be broken into digits. For example, 1903 is composed of 1, 9, 0, and 3. To write the Roman numeral, each of the non-zero digits should be treated separately. In the above example, 1,000 = M, 900 = CM, and 3 = III. Therefore, 1903 = MCMIII.