TobySoft's Converticus utilitity converts between Arabic (Western) numbers and Roman Numerals up to 999,999.
Run
the installation program and follow the on-screen instructions.
Select "Converticus" from Windows Control Panel|Add/Remove Programs.
1. Double click on Converticus.exe or select it from the Windows Start Button|Programs and you'll see a window like this:
2. Enter a Western or Roman number:
Roman number input is automatically capitalised and non-Roman characters are ignored.
4. Click OK and the Western equivalent appears in the appropriate box.
The Version menu option shows the version of the program.
The Help menu brings up this help document.
The Roman Numeral character set is:
I 1
V 5
X 10
L 50
C 100
D 500
M 1,000
For the following, "/" represents a bar over the top of the letter. This is difficult to reproduce on computers. The bar multiplies the 'root' value by 1,000.
/V 5,000 (5*1,000)
/X 10,000 (10*1,000)
/L 50,000 (50*1,000)
/C 100,000 (100*1,000)
/D 500,000 (500*1,000)
/M 1,000,000 (1,000*1,000)
If a lesser value follows a greater value e.g. VI, then the values are added: V+I = 5+1 = 6. There can be up to three consecutive lesser values. VI, VII, & VIII are all valid for 6, 7 & 8 respectively, but VIIII is not valid for 9. The only exception to this is IIII (4) as seen on some clocks.
If a lesser value preceeds a greater value e.g. IV, then the lesser value is subtracted from the greater value: V-I = 5-1 = 4. There can only be one lesser value. IIX is not valid to represent 8, VIII is the correct form. The lesser value must be the first power of 10 less than the greater value (1, 10, 100, 1,000 etc). So IC is not correct for 99, but XCIX is: (C-X)+(X-I) = (100-10)+(10-1) = 90+9 = 100. LM is not correct for 950, but CML is: (M-C)+(L) = (1,000-100)+50 = 900+50 = 950.
The easiest way to calculate the Roman equivalent of a number is to split it up into units, tens, hundreds, etc., calculate each value separately and add the resutant strings of characters together. e.g. the number 1,978 splits as follows:
1 thousand = M (1,000)
9 hundreds = CM (1,000-100)
7 tens = LXX (50+10+10)
8 units = VIII (5+1+1+1)
So 1,978 is MCMLXXVIII
64,387 splits as:
6 tens of thousands = /L/X (50,000+10,000)
4 thousands = M/V (5,000-1,000)
3 hundreds = CCC (100+100+100)
8 tens = LXXX (50+10+10+10)
7 units = VII (5+1+1)
So 64,387 is /L/XM/VCCCLXXXVII
These are the 'key' values up to 9,000:
1 I (1)
2 II (1+1)
3 III (1+1+1)
4 IV (5-1)
5 V (5)
6 VI (5+1)
7 VII (5+1+1)
8 VIII (5+1+1+1)
9 IX (10-1)
10 X (10)
20 XX (10+10)
30 XXX (10+10+10)
40 XL (50-10)
50 L (50)
60 LX (50+10)
70 LXX (50+10+10)
80 LXXX (50+10+10+10)
90 XC (100-10)
100 C (100)
200 CC (100+100)
300 CCC (100+100+100)
400 CD (500-100)
500 D (500)
600 DC (500+100)
700 DCC (500+100+100)
800 DCC (500+100+100+100)
900 CM (1,000-100)
1,000 M (1,000)
2,000 MM (1,000+1,000)
3,000 MMM (1,000+1,000+1,000)
4,000 /VM (5,000-1,000)
5,000 /V (5,000)
6,000 /VM (5,000+1,000)
7,000 /VMM (5,000+1,000+1,000)
8,000 /VMMM (5,000+1,000+1,000+1,000)
9,000 M/X (10,000-1,000)