Learn Roman numerals

Count in Roman numbers. What is the largest number you can write? Print out these charts to learn.

1 = I
2 = II
3 = III
4 = IV = IIII
5 = V
6 = VI
7 = VII
8 = VIII = IIX
9 = IX = VIIII
10 = X
11 = XI
12 = XII
13 = XIII
14 = XIV
15 = XV
16 = XVI
17 = XVII
18 = XVIII
19 = XIX
20 = XX
21 = XXI
22 = XXII
23 = XXIII
24 = XXIV
25 = XXV
26 = XXVI
27 = XXVII
28 = XXVIII
29 = XXIX
30 = XXX
31 = XXXI
32 = XXXII
33 = XXXIII
40 = XL
50 = L
60 = LX
70 = LXX
80 = LXXX
90 = XC
99 = XCIX
100 = C
200 = CC
300 = CCC
400 = CD
500 = D
600 = DC
700 = DCC
800 = DCCC
900 = CM
1000 = M

Roman numerals are constructed using additive and subtractive principles.

Addition is the main rule. Simply add up the digits. Example: XXI = 10+10+1 = 21.

Subtraction happens when a smaller digit comes before a larger digit. In that case, deduct the smaller digit from the larger digit. Example: IX = 10−1 = 9. The usual subtractive combinations are: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). Note that other combinations are not generally used, so 99 is not IC, but XCIX = 100−10 + 10−1 = 99.

Subtraction is a shorthand for four successive digits. Thus, IIII=IV, XXXX=XL and so on. Both forms are possible.

Number zero does not exist in Roman numerals.

Large Roman numerals
Thousands
1000 = M
2000 = MM
3000 = MMM
4000 = MMMM
5000 = V
6000 = VM
7000 = VMM
8000 = VMMM
9000 = VMMMM
10000 = X
20000 = XX
30000 = XXX
40000 = XL
50000 = L
60000 = LX
70000 = LXX
80000 = LXXX
90000 = XC
100000 = C = I
200000 = CC = II
300000 = CCC = III
400000 = CD = IV
500000 = D = V
600000 = DC = VI
700000 = DCC = VII
800000 = DCCC = VIII
900000 = CM = IX
Millions
1000000 = M = X
2000000 = MM = XX
3000000 = MMM = XXX
4000000 = IV = XL
5000000 = V = L
6000000 = VI = LX
7000000 = VII = LXX
8000000 = VIII = LXXX
9000000 = IX = XC
10000000 = X = C
20000000 = XX = CC
30000000 = XXX = CCC
40000000 = XL = CD
50000000 = L = D
60000000 = LX = DC
70000000 = LXX = DCC
80000000 = LXXX = DCCC
90000000 = XC = CM
100000000 = C = M
200000000 = CC = MM
300000000 = CCC = MMM
400000000 = CD
500000000 = D
600000000 = DC
700000000 = DCC
800000000 = DCCC
900000000 = CM
Milliards
(billions)
1000000000 = M
2000000000 = MM
3000000000 = MMM
nn = 1000  nn
nn = 100,000  nn
nn = 1,000,000  nn

In order to write large numerals, one draws lines above or around numbers. This causes multiplication as per the table above.

Large Roman numerals, archaic
Hundreds
500   =  = D
Thousands
1000 = CIƆ = ↀ
2000 = CIƆCIƆ
3000 = CIƆCIƆCIƆ
4000 = CIƆIƆƆ
5000 = IƆƆ = ↁ
6000 = IƆƆCIƆ
7000 = IƆƆCIƆCIƆ
8000 = IƆƆCIƆCIƆCIƆ
9000 = CIƆCCIƆƆ
10000 = CCIƆƆ = ↂ
20000 = CCIƆƆCCIƆƆ
30000 = CCIƆƆCCIƆƆCCIƆƆ
40000 = CCIƆƆIƆƆƆ
50000 = IƆƆƆ
60000 = IƆƆƆCCIƆƆ
70000 = IƆƆƆCCIƆƆCCIƆƆ
80000 = IƆƆƆCCIƆƆCCIƆƆCCIƆƆ
90000 = CCIƆƆCCCIƆƆƆ
100000 = CCCIƆƆƆ



500000 = IƆƆƆƆ
Million
1000000 = CCCCIƆƆƆƆ

There are archaic forms of Roman numbers starting from 500. The system starts with CIƆ being one thousand. Adding C and Ɔ multiplies the figure by 10. Halving the numeral (leave out the C's on the left) divides the number by 2. Thus, CCIƆƆ is 101000 = 10000 and IƆƆ is a half of that, 5000.

The archaic forms can be written in two alternative ways, as shown in the image below.

See also: Roman numerals complete list (1-3,999,999,999)

©Tuomas Salste