Numbers

Numerals up to nine are written out in full, from 10 upwards numerals are written in figures. Do not mix the two in the same phrase. 

Numerals up to nine are written out in full, from 10 upwards numerals are written in figures. Do not mix the two in the same phrase.
Example: Between eight and twelve people

Million and billion are often written in full in the case of smaller numbers e.g. six million, five billion but 50 million or 500 billion. Multiples of ten and thousand are often written in full, e.g., fifty, three hundred, four thousand.

Use figures for numerals in formal notices.
Examples: on 4 October, 42 ECTS, speed limit 100 km.

Use figures when denoting rankings.
Examples: 1st, 2nd, 3rd, 7th, 38th.

Fractions should be written out in words, but only when the numerals are below ten. Fractions should be hyphenated.
Examples: one-eighth, two-thirds. But: a quarter. If fractions go with a whole number, they should be written in figures. Example: 4½, 2¾.

For sums of money with four or more digits, use commas to denote the thousands and millions.
Examples: 1,523 euro, 430,000 euro, € 430,000, € 4,300,000, 4,300,000 euro.

Use a dot before decimals.
Example: € 1,123.10

NB Dutch 'miljard' is English 'billion'.