La Hawla wa la Quwata illa billa
(There is no might no power expect with ALLAAH)
we shall see from the authentic ahadith and scholars opinion which should be done i;e either loudly or silently or both
(1) AHadith which says “Bismillah” should be recited loudly
(a)An-Nasa’i recorded in his Sunan, Ibn Hibban and Ibn Khuzaymah in their Sahihs and Al-Hakim in the Mustadrak, that Abu Hurayrah once performed the prayer and recited Bismillah aloud. After he finished the prayer, he said, “Among you, I perform the prayer that is the closest to the prayer of the Messenger of Allah .” Ad-Daraqutni, Al-Khatib and Al-Bayhaqi graded this Hadith Sahih.
(b) In Sahih Al-Bukhari it is recorded that Anas bin Malik was asked about the recitation of the Prophet . He said, “His recitation was unhurried.” He then demonstrated that and recited, while lengthening the recitation of Bismillah Ar-Rahman Ar-Rahim, Also, in the Musnad of Imam Ahmad, the Sunan of Abu Dawud, the Sahih of Ibn Hibban and the Mustadrak of Al-Hakim – it is recorded that Umm Salamah said, “The Messenger of Allah used to distinguish each Ayah during his recitation,
In the Name of Allah, the Most Gracious, the Most Merciful. All praise and thanks be to Allah, the Lord of all that exists, the Most Gracious, the Most Merciful. The Owner of the Day of Recompense.”
Ad-Daraqutni graded the chain of narration for this Hadith Sahih
(c)Furthermore, Imam Abu `Abdullah Ash-Shafi`i and Al-Hakim in his Mustadrak, recorded that Mu`awiyah led the prayer in Al-Madinah and did not recite the Bismillah. The Muhajirin who were present at that prayer criticized that. When Mu`awiyah led the following prayer, he recited the Bismillah aloud.
(2)AHadith which says “Bismillah” should be recited silently
(a) It was narrated from Anas (may Allah be pleased with him) that the Prophet (blessings and peace of Allah be upon him), and Abu Bakr and ‘Umar (may Allah be pleased with them both) began the prayer with the words “Al-hamdu Lillahi Rabbi l-‘Aalameen (Praise be to Allah, Lord of the Worlds).”
Narrated by al-Bukhaari (743)
(b)according to a report narrated by Ahmad (12868), “They did not recite out loud the words ‘Bismillah ir-Rahmaan ir-Raheem (In the name of Allah, the Most Gracious, the Most Merciful).’”
(3) Opinion of contemporary scholars
Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allah have mercy on him) was asked:
What is the ruling on reciting the basmalah out loud?
The more correct view is that the basmalah should not be recited out loud, and that the Sunnah is to recite it quietly, because it is not part of al-Faatihah. But if it is recited out loud sometimes, there is nothing wrong with that. In fact some of the scholars said that it should be recited out loud sometimes, because it was recited from the Prophet (blessings and peace of Allah be upon him) that he used to recite it out loud. But what is proven from him (blessings and peace of Allah be upon him) is that he did not recite it out loud, and this is the preferred view, that he did not recite it out loud.
But if (the imam) recites it out loud in order to soften the hearts of people whose madhhab says that it is to be recited out loud, then I hope that there is nothing wrong with that.
End quote from Majmoo‘ Fataawa ash-Shaykh Ibn ‘Uthaymeen (13/109)
(4) Check about this in tafseer ibn katheer Bismillah should recite aloud .
ALLAAH knows best