al-Takbir al-Mutlaq

Q: When do we begin making takbir for Eid al-Fitr and do we make it after the prayers in congregation?

A: It is recommended to perform the unrestricted takbīr on both of the two ʿĪds, saying "Allahu akbar Allahu akbar la illaha illallah, wallahu akbar Allahu akbar wa lillahil hamd".

It is also recommended to make this unrestricted takbīr audible in the masjids, homes, and roads, whether one is residing or traveling, in every place where the remembrance of Allah is permissible.

It is recommended to raise one’s voice in the takbīr for everyone except women who should make it in a low voice.

This unrestricted takbīr becomes more strongly emphasized beginning from the night before each of the two ʿĪds, meaning from sunset on the evening preceding them.

It is especially emphasized when going out to attend the ʿĪd prayers. The takbīr continues until the conclusion of the sermon on the day of ʿĪd.

Once the sermon concludes, the takbīr is to be discontinued.

The unrestricted takbīr is more emphasized for ʿĪd al-Fiṭr.

In ʿĪd al-Fiṭr, takbīr is not made after the obligatory prayers.

As for ʿĪd al-Aḍḥā, the unrestricted takbīr begins from the start of the first ten days of Dhū al-Ḥijjah.

This continues until the conclusion of the sermon on the Day of Sacrifice (Yawm al-Naḥr).

As for the restricted takbīr — meaning the one tied to the end of prayers — it applies to ʿĪd al-Aḍḥā only.

Source: Sharh al-Muntaha and Kashshaf al-Qina