Assalamualaikum, if someone intends to pray Fajr but they wake up 5minutes before sunrise and then whilst they are praying it goes past sunrise, is their prayer invalid? Because when I first searched this online all the answers says just to wake up and pray immediately even if you're late. So I assumed you didn't have to make intention of qaza? Jzk
Alaikumassalam wa rahmatullah,
The Prophet 
says:
"Whoever could get one rak`a (of the Fajr prayer) before sunrise, he has accomplished the (morning) prayer and whoever could get one rak`a of the `Asr prayer before sunset, he has accomplished the (`Asr) prayer."
Sahih al-Bukhari 579; a version is also in Sahih Muslim 608 a
So if you start the prayer, finish one rakʿa, then if the sun rises, then you have performed it correctly and there is no need to redo it. But if the sun rises during the first rakʿa, there are different opinions on whether the prayer is valid or not. According to some scholars, if the sun rises during the first rakʿa, then the prayer becomes a qaḍāʾ prayer, meaning the person has missed fajr (but they should still continue the prayer, considering it a qaḍāʾ prayer for fajr). According to others, if a person performs the takbirat al-iḥrām (the first “Allahu akbar” at the beginning of the prayer) before sunrise, then they have accomplished fajr and it is not qaḍāʾ.
Source:
- Fatwa from the Qatari Fatwa Authority (Arabic PDF)