Round your lips into a tight circle. Lift the back of your tongue toward the soft palate and add voice.

Americans pronounce within as wih-DHIHN (/wɪˈðɪn/). Stress falls on the second syllable — keep everything else short and quick. You'll hear it in sentences like "She set a goal to run a 5k race within three months" or "He reviewed his notes within twenty-four hours of the lecture" — more examples below.
Record yourself saying "within" and play it back. The mic stays on your device — nothing's uploaded.
2 syllables, 5 sounds. Tap a syllable to jump to its row, then explore each sound's mouth shape and how it's made.
Place your tongue tip between or behind your front teeth, turn your vocal cords on, and push air through the gap.
Drop your jaw slightly with relaxed lips. Touch the tongue tip behind the bottom front teeth and arch the top-front toward the roof.

Touch the tip or front edge of your tongue to the roof of your mouth behind your teeth. Air flows through your nose.

Click any sentence to see the full breakdown — every link, every reduction, every flap-T.
The textbook way isn't wrong — it's just not how anyone actually says it.
Stress falls on the second syllable, not the others. Stretch DHIHN — keep everything else short and quick.