Du’as for Fasting

When beginning the fast- Suhur

وَبِصَوْمِ غَدٍ نَّوَيْتَ مِنْ شَهْرِ رَمَضَانَ Wa bisawmi ghadinn nawaiytu min shahri ramadan

I intend to keep the fast for tomorrow in the month of Ramadan [abu Dawud]

When breaking the fast- Iftar

اللَّهُمَّ اِنِّى لَكَ صُمْتُ وَبِكَ امنْتُ [وَعَلَيْكَ تَوَكَّلْتُ] وَعَلَى رِزْقِكَ اَفْطَرْتُ

Allahumma inni laka sumtu wa bika aamantu [wa 'alayka tawakkaltu] wa ‘ala rizq-ika aftarthu

O Allah! I fasted for You and I believe in You [and I put my trust in You] and I break my fast with Your sustenance ["wa 'alayka tawakkaltu" is quoted in some books of knowledge - but not all, hence it is in brackets] [abu Dawud]

ذَهَبَ الظَّمَأُ وَ ابْتَلَّتِ الْعُرُوقُ، وَ ثَبَتَ الأجْرُ إنْ شَاءَ اللَّهُ

dhahabadh-dhama’u wab-tallatil ‘urūūqi, wa thabatal arju inshaAllah

The thrist is gone, the veins are moistened and the reward is confirmed, if Allah [Ta'ala] Wills [abu Dawud 2:306]