Can I do dhikr without wudu?

Why wudu isn't required

Wudu is a condition for the prayer (salah) and, for most scholars, for touching a printed Quran. Dhikr is different. Aisha said: "The Apostle of Allah (ﷺ) used to remember Allah at all moments" (Sahih Muslim 373). Scholars point out that "all moments" includes times when he was not in wudu.

Ibn Abbas, who spent a night at the Prophet's house, described how the Prophet ﷺ woke up, rubbed the sleep from his face and recited the last ten verses of Surah Al Imran before getting up to make wudu (Sahih al-Bukhari 183). So even Quran recitation from memory came before wudu here.

Wudu is still the better state

Once, a man greeted the Prophet ﷺ while he was urinating. He waited until he had made wudu, then replied and explained: "I disliked remembering Allah except in the state of purification" (Sunan Abi Dawud 17). Scholars understand this as a preference, not a rule, because of the many reports of him remembering Allah at all times. So:

• If you're already in wudu: great, that's the ideal.
• If you're not: carry on with your dhikr. Don't let it become a reason to skip it.
• Before sleep: many people make wudu and then do their bedtime adhkar, which combines both.

What about after sex or on a period?

Even in a state that requires a full shower (ghusl), dhikr and dua are allowed. The Prophet ﷺ once told Abu Huraira, who had avoided him for this reason, "Subhan Allah! A believer never becomes impure" (Sahih al-Bukhari 283). What changes in that state is mainly the prayer, touching the mushaf and, for most scholars, reciting the Quran itself. For the period question, see Can I do dhikr on my period?

Dhikr vs. reading the Quran

Keep the difference in mind: dhikr phrases and duas are open to you in any state. Holding a printed Quran is where the wudu discussion starts, and scholars differ on phones and apps. See Can I read the Quran on my phone without wudu? and Can I listen to the Quran while driving or doing chores?