When beginning the fast

وَبِصَوْمِ غَدٍ نَّوَيْتَ مِنْ شَهْرِ رَمَضَا
Wa bisawmi ghadinn nawaiytu min shahri ramadan
(I intend to keep the fast today in the month of Ramadan)
[abu Dawud

**When breaking the fast

اللَّهُمَّ اِنِّى لَكَ صُمْتُ وَبِكَ امنْتُ وَ عَلى رِزْقِكَ اَفْطَرْتُ
Allahumma inni laka sumtu wa bika aamantu wa ‘ala rizq-ika aftarthu
(O Allah! I fasted for You and I believe in You and I break my fast with Your sustenance)[abu Dawud]