Possessive 's (Jan's, vaders)

Just like in English, you can show possession in Dutch by adding an s to a name or a family member. However, the rules for when to use an apostrophe are slightly different.

The Attached -s

For most words, including those ending in a consonant or an unstressed -e (like tante), attach an -s directly to the end of the word. Do not use an apostrophe.

Where are Father's glasses?
Waar is vaders bril?
My uncle's computer is broken.
Mijn ooms computer is kapot.
My aunt's partner is a good doctor.
Mijn tantes partner is een goede arts.

The Apostrophe -'s

If a word ends in a single, open vowel (like -a, -i, -o, or -u), adding an -s directly would change how the vowel is pronounced. To keep the vowel sound long, Dutch uses an apostrophe before the s ('s).

I do not see Grandma's wallet.
Ik zie oma's portemonnee niet.
Grandpa's glasses are also lost.
Opa's bril is ook kwijt.