Short answer
No, not for passing thoughts. The Prophet ﷺ said Allah has pardoned his ummah for what their souls whisper to them, as long as they do not act on it or speak it. If you intend a sin and then leave it for Allah's sake, it is written as a good deed. A firm resolve settled in the heart is different and can be blamed.
Passing thoughts (khawatir) and inner talk are forgiven. Scholars distinguish them from 'azm, a firm decision settled in the heart, which can be sinful, and from sins of the heart itself, such as envy, arrogance and showing off, for which a person is accountable.
The four schools agree on this.
Explanation
When the verse "whether you show what is within yourselves or conceal it, Allah will bring you to account for it" (2:284) came down, the Companions found it very hard. They submitted, and Allah then revealed: "Allah does not charge a soul except [with that within] its capacity" (2:286). Thoughts that come uninvited are beyond our control, so they are not counted against us.
The Prophet ﷺ said: "Allah has pardoned my ummah for what their souls whisper to them, as long as they do not act on it or speak it." And in a hadith about how deeds are written: whoever intends a bad deed and does not do it, Allah writes it as a full good deed; if he does it, it is written as one bad deed. Scholars explain the good deed is written when he leaves the sin for Allah's sake.
The scholars describe stages: a passing thought, then thinking it over, then inclining to it, then a firm resolve. The first stages are forgiven. A firm resolve that a person would act on if he could, with nothing stopping him but circumstance, is blameworthy. Separately, some sins live in the heart: envy, arrogance, hatred of Allah's commands and showing off. You are accountable for these, and must treat them.
When does any of this count? From puberty, with a sound mind; see at what age is a child accountable? If unwanted thoughts trouble you, especially about faith, that distress is a sign of iman, not of sin. See also do angels record everything you do? and mental health in Islam.
The evidence
Quran, Surah Al-Baqara 2:284
لِّلَّهِ مَا فِى ٱلسَّمَٰوَٰتِ وَمَا فِى ٱلْأَرْضِ ۗ وَإِن تُبْدُوا۟ مَا فِىٓ أَنفُسِكُمْ أَوْ تُخْفُوهُ يُحَاسِبْكُم بِهِ ٱللَّهُ ۖ فَيَغْفِرُ لِمَن يَشَآءُ وَيُعَذِّبُ مَن يَشَآءُ ۗ وَٱللَّهُ عَلَىٰ كُلِّ شَىْءٍۢ قَدِيرٌ ﴿٢٨٤﴾
To Allah belongs whatever is in the heavens and whatever is in the earth. Whether you show what is within yourselves or conceal it, Allah will bring you to account for it. Then He will forgive whom He wills and punish whom He wills, and Allah is over all things competent.
The verse that worried the Companions.
Quran, Surah Al-Baqara 2:286
لَا يُكَلِّفُ ٱللَّهُ نَفْسًا إِلَّا وُسْعَهَا ۚ لَهَا مَا كَسَبَتْ وَعَلَيْهَا مَا ٱكْتَسَبَتْ ۗ رَبَّنَا لَا تُؤَاخِذْنَآ إِن نَّسِينَآ أَوْ أَخْطَأْنَا ۚ رَبَّنَا وَلَا تَحْمِلْ عَلَيْنَآ إِصْرًۭا كَمَا حَمَلْتَهُۥ عَلَى ٱلَّذِينَ مِن قَبْلِنَا ۚ رَبَّنَا وَلَا تُحَمِّلْنَا مَا لَا طَاقَةَ لَنَا بِهِۦ ۖ وَٱعْفُ عَنَّا وَٱغْفِرْ لَنَا وَٱرْحَمْنَآ ۚ أَنتَ مَوْلَىٰنَا فَٱنصُرْنَا عَلَى ٱلْقَوْمِ ٱلْكَٰفِرِينَ ﴿٢٨٦﴾
Allah does not charge a soul except [with that within] its capacity. It will have [the consequence of] what [good] it has gained, and it will bear [the consequence of] what [evil] it has earned. "Our Lord, do not impose blame upon us if we have forgotten or erred. Our Lord, and lay not upon us a burden like that which You laid upon those before us. Our Lord, and burden us not with that which we have no ability to bear. And pardon us; and forgive us; and have mercy upon us. You are our protector, so give us victory over the disbelieving people."
Shows people are not charged with what is beyond their control.
Sahih al-Bukhari 5269
Sahih... إِنَّ اللَّهَ تَجَاوَزَ عَنْ أُمَّتِي مَا حَدَّثَتْ بِهِ أَنْفُسَهَا، مَا لَمْ تَعْمَلْ أَوْ تَتَكَلَّمْ ...
"Allah has pardoned my ummah for what their souls whisper to them, as long as they do not act on it or speak it."
Passing thoughts are not punished.
Sahih al-Bukhari 6491
Sahih... وَمَنْ هَمَّ بِسَيِّئَةٍ فَلَمْ يَعْمَلْهَا كَتَبَهَا اللَّهُ لَهُ عِنْدَهُ حَسَنَةً كَامِلَةً ...
"Whoever intends a bad deed and does not do it, Allah writes it with Him as a full good deed."
Leaving a sin you intended is rewarded.
Where the ruling is recorded
- Sharh al-Nawawi ala Sahih Muslim, Book of Faith, chapter on Allah pardoning inner thoughts. Distinguishes passing thoughts, which are pardoned, from a settled resolve.
- Umdat al-Qari (Badr al-Din al-Ayni), Book of softening hearts, the hadith on intending good and bad deeds. The Hanafi commentary explains how intentions are recorded.
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.