The symbols are I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1000. Symbols are added from left to right, except when a smaller one comes before a larger one, which means subtract: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900.
For example 2026 = MM (2000) + XX (20) + VI (6) = MMXXVI.
Common questions
What is 2026 in Roman numerals?
MMXXVI.
Why does it stop at 3999?
Standard Roman numerals have no symbol above M, so 3999 (MMMCMXCIX) is the largest number written without special overline notation.