Short answer
Yes. Stray thoughts, even many of them, do not break the prayer, and the four schools agree it is valid. What you lose is reward: you are rewarded for the part of the prayer you were present in. Keep bringing your mind back, and do not repeat the prayer because of thoughts.
Khushu' (presence and humility) is the spirit of the prayer and is sunnah, not a condition of validity. A prayer with wandering thoughts is valid and no repetition is needed. Deliberately thinking about worldly matters during prayer is disliked.
The four schools agree on this.
Explanation
Every Muslim knows this struggle, and the Prophet ﷺ described it. He said that when the iqamah ends, Shaytan comes and whispers to a person, "Remember this, remember that", things he had not thought of, until he does not know how much he has prayed. A Companion complained that Shaytan came between him and his prayer; the Prophet ﷺ told him that this was a devil called Khinzab, and taught him to seek refuge in Allah and dry-spit lightly to his left three times. He did so and it left him.
Your prayer is valid. The fard parts of salah are actions and words; a thought does not undo them. But the reward follows presence of heart: a hadith in Abu Dawud says a person may finish his prayer with only a tenth of it, or less, written for him. So the aim is to grow in focus, not to give up.
Practical help:
- Learn the meaning of al-Fatiha and the short surahs you recite; see al-Fatiha word by word.
- Look at the place of sajdah while standing, and keep still.
- Slow down: pause in ruku and sajdah long enough to say the tasbih calmly.
- Remove distractions first: phone on silent, bathroom first, eat if food is ready.
- When you notice you have drifted, return gently to the words. Each return is worship.
- Change surahs sometimes, so recitation does not become automatic.
If the thoughts are distressing or obsessive, such as blasphemous thoughts you hate, or constant doubts about whether your prayer counts, this is waswasa. Ignore it and do not repeat prayers for it. If it takes over your life, speaking to a scholar and a Muslim therapist helps; see mental health in Islam. For miscounting rakats, see not sure how many rakats you prayed.
The evidence
Quran, Surah Al-Muminoon 23:1-2
بِسْمِ ٱللَّهِ ٱلرَّحْمَٰنِ ٱلرَّحِيمِ قَدْ أَفْلَحَ ٱلْمُؤْمِنُونَ ﴿١﴾ ٱلَّذِينَ هُمْ فِى صَلَاتِهِمْ خَٰشِعُونَ ﴿٢﴾
Certainly will the believers have succeeded: They who are during their prayer humbly submissive
Humble presence in prayer is a quality of successful believers.
Sahih al-Bukhari 608
Sahih... حتى يخطر بين المرء ونفسه يقول اذكر كذا اذكر كذا ...
"He comes between a man and his own mind, saying: remember this, remember that, things he had not remembered."
Stray thoughts in prayer come from Shaytan and are expected.
Sahih Muslim 2203
Sahih... ذاك شيطان يقال له خنزب ...
"That is a devil called Khinzab; when you sense him, seek refuge in Allah from him and dry-spit to your left three times."
The remedy the Prophet ﷺ taught for distraction in prayer.
Where the ruling is recorded
- Radd al-Muhtar (Ibn Abidin), Kitab al-Salah, chapter on what is disliked in the prayer. Thoughts in the prayer do not invalidate it; deliberately pursuing worldly thoughts is disliked.
- Nur al-Idah with Maraqi al-Falah, Chapter on the sunnahs and etiquette of prayer. Khushu' and looking at the place of sajdah are among the etiquettes of prayer.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.