In bank account they give interest like most of banks. So We Muslims using Interest money is Haram. The matter is I can give that money to poor people as Sadaqa, question is can I give that money to non Muslim poor people?
ALLAH azza wa jal say:
لا يَنْهَاكُمُ اللَّهُ عَنِ الَّذِينَ لَمْ يُقَاتِلُوكُمْ فِي الدِّينِ وَلَمْ يُخْرِجُوكُم مِّن دِيَارِكُمْ أَن تَبَرُّوهُمْ وَتُقْسِطُوا إِلَيْهِمْ ۚ إِنَّ اللَّهَ يُحِبُّ الْمُقْسِطِينَ (8) إِنَّمَا يَنْهَاكُمُ اللَّهُ عَنِ الَّذِينَ قَاتَلُوكُمْ فِي الدِّينِ وَأَخْرَجُوكُم مِّن دِيَارِكُمْ وَظَاهَرُوا عَلَىٰ إِخْرَاجِكُمْ أَن تَوَلَّوْهُمْ ۚ وَمَن يَتَوَلَّهُمْ فَأُولَٰئِكَ هُمُ الظَّالِمُونَ (9)
Allah does not forbid you from those who do not fight you because of religion and do not expel you from your homes - from being righteous toward them and acting justly toward them. Indeed, Allah loves those who act justly (8) Allah only forbids you from those who fight you because of religion and expel you from your homes and aid in your expulsion - [forbids] that you make allies of them. And whoever makes allies of them, then it is those who are the wrongdoers (9) [Al-Mumtahanah 8-9]
so here it is explicitly stated that it is allowed unless they fight Muslims and expel you from your homes. and being "righteous" include giving them "Sadaqa"
In another aya, azza wa jal say: "
وَيُطْعِمُونَ الطَّعَامَ عَلَىٰ حُبِّهِ مِسْكِينًا وَيَتِيمًا وَأَسِيرًا
And they give food in spite of love for it to the needy, the orphan, and the captive [Al-Insan 9]
and people who were in captive, were non-Muslims at that time, so it is allowing you to give food, and giving food is Sadaqa and it is Ihsan.
keep in mind that it is allowed unless they fight you, or going to use this money in doing haram actions.