Can I make wudu with hair dye or henna?

Colour is fine, coatings are not

The rule for wudu is simple: water has to reach the parts you wash or wipe. Things that only stain or dye, without forming a layer, don't get in the way. That's why scholars of all four schools agree that wudu is valid with:

• Permanent and semi-permanent hair dye once it has been rinsed out.
• Henna on the hair, hands or feet once the paste has dried and been removed, leaving only the orange-brown stain.
• Katam and other plant dyes used for grey hair.

What does need to come off before wudu is anything that sits on top: wet or dried henna paste, "black henna" stickers, heavy gel or wax that clumps the hair, coloured hair spray, or nail polish. See Can I wear henna as a Muslim woman?

Wiping over dyed hair

In wudu you wipe your head with wet hands (Quran 5:6). Dyed hair is wiped just like undyed hair. Scholars differ on how much of the head to wipe: the Maliki and Hanbali schools say the whole head, the Hanafi school a quarter, and the Shafi'i school any part. If you use a styling product, a light one usually lets water reach the hair; a thick, hard layer may not.

Dyeing your hair is a sunnah for grey hair

Dyeing hair isn't just allowed; for grey hair it's encouraged. When Abu Quhafah was brought to the Prophet ﷺ with hair white as snow, he said to change it with something but avoid black (Sahih Muslim 2102). Scholars differ about pure black dye: many dislike or forbid it, while others allow it in some cases. Other colours, including fun ones, are generally fine as long as they aren't meant to imitate a sinful group. See Can I dye my hair?

A note for women dyeing at home

If you dye your hair right after a ghusl or wudu, your purity isn't affected. Just make sure the dye is fully rinsed out before your next wudu. A quick shower rinse is enough. Makeup works on the same principle; see Can I make wudu with makeup on?