The Prophet ﷺ said about a man who has sexual intercourse with a menstruating woman: He should give one or half dinar as sadaqah. (Using translation from Abū Dāʾūd 2168)

عَنِ النَّبِيِّ ﷺ فِي الرَّجُلِ يَأْتِي امْرَأَتَهُ وَهِيَ حَائِضٌ قَالَ يَتَصَدَّقُ بِدِينَارٍ فَإِنْ لَمْ يَجِدْ فَنِصْفِ دِينَارٍ

[Machine] About the Prophet ﷺ, regarding a man who had intercourse with his wife while she was menstruating, he said, "If it was a dark red blood, then he should give a dinar in charity, and if it was yellowish, then half a dinar."

عَنِ النَّبِيِّ ﷺ فِي رَجُلٍ جَامِعَ امْرَأَتَهُ وَهِيَ حَائِضٌ قَالَ «إِنْ كَانَ دَمًا عَبِيطًا فَلْيَتَصَدَّقْ بِدِينَارٍ وَإِنْ كَانَ صُفْرَةً فَبِنِصْفِ دِينَارٍ»

[Machine] Regarding the Prophet ﷺ on the topic of a man having relations with his wife while she is menstruating, he said: "If the blood is bright red, then the expiation is one dinar. But if it is yellowish, then the expiation is half a dinar."

عَنِ النَّبِيِّ ﷺ فِي الَّذِي يَأْتِي امْرَأَتَهُ وَهِيَ حَائِضٌ قَالَ «إِنْ كَانَ الدَّمُ عَبِيطًا فَدِينَارٌ وَإِنْ كَانَ فِيهِ صُفْرَةٌ فَنِصْفُ دِينَارٍ»

عَنِ ابْنِ عَبَّاسٍ رَضِي اللَّهُ عَنْهُمَا فِي الَّذِي يَقَعُ عَلَى امْرَأَتِهِ وَهِيَ حَائِضٌ إن كان الدم عبيط فَلْيَتَصَدَّقْ بِدِينَارٍ وَإن كَانَ صُفْرَةً فَنِصْفُ دِينَارٍ

The Prophet ﷺ said about a person who had intercourse with his wife while she was menstruating: He must give one dinar or half a dinar in alms. Abu Dawud said: The correct version says si: One dinar or half a dinar. Shu'bah (a narrator) did not sometimes narrate this tradition as a statement of the Prophet ﷺ. (Using translation from Abū Dāʾūd 264)

"إذا أتى الرَّجلُ امرأتَهُ وهِىَ حَائِضٌ فليتصدقْ بدينار، أو نصف دينارٍ" .