1. Non-fulfillment of Any Condition (Shart) of Salah

If any condition necessary for Salah is not fulfilled, Salah becomes invalid.

If during Salah any act causing impurity occurs, or if an unexcused impurity falls on the body, clothing, or place of prayer, or if the ’Awrah (private parts) becomes exposed, or if one turns away from the Qiblah, then the Salah becomes invalid.

However:

• If the impurity that fell is dry and is quickly removed without touching or carrying it, the Salah does not become invalid.
• If the Awrah becomes exposed due to something like the wind but is immediately covered again without excessive movement, the Salah does not become invalid.
  

2. Omission of an Obligatory Component (Fard) of Salah

• If what is omitted is Niyyah (intention) or Takbiratul Ihram (opening Takbir), whether done deliberately or forgetfully, Salah becomes invalid.
• If any other obligatory component is omitted:
  • If deliberately omitted, Salah becomes invalid.
  • If omitted forgetfully, it must be made up (corrected); otherwise, the Salah remains invalid.
    

3. Acts That Invalidate Salah Whether Done Deliberately or Forgetfully

• Considering Salah as broken, or doubting whether to complete or stop the prayer (e.g., thinking, “If the bus comes, I’ll stop the prayer”).
• Performing three or more consecutive actions that are not part of Salah (e.g., taking three steps, or moving heavy limbs like hands three times consecutively).

However:

• Moving light organs (like fingers, eyelids, lips, or tongue) excessively does not invalidate Salah.
• If such movements are done playfully without need, Salah becomes invalid.
• If movements are due to an unavoidable reason (like illness), it does not invalidate Salah.
  

Movement count:

• Placing one foot counts as one movement, placing the second foot counts as the second movement.
• Similarly, moving a hand forward and then bringing it back counts as two separate movements.

4. Mistaking the Obligatory Components for Sunnah

Thinking that an obligatory act of Salah is only a Sunnah invalidates the Salah.

5. Impurities Entering the Body

If heavy impurities such as food residue, phlegm, or blood-mixed urine enter the body.

6. Doubting Essential Elements

Doubting whether the Niyyah was made or whether Takbiratul Ihram was pronounced invalidates the Salah.

7. Matters That Invalidate Salah Only if Done Deliberately

Unnecessarily increasing a physical act of Salah (e.g., adding extra Ruku or Sujud intentionally).

Adding verbal acts:

• If extra verbal components (other than Salam or Takbir with the intention of starting a new Salah) are added, Salah is not invalidated.
• However, if one repeats Salam or says “Allahu Akbar” with the intention of beginning another Salah, the current Salah becomes invalid.
  

8. Uttering Unrelated Speech

• Uttering two consecutive letters that are not Quran, Dhikr, or Du’a deliberately, or uttering a single letter with meaning deliberately, both invalidate Salah.