When a noon sakinah (نْ) or tanween (ـً ـٍ ـٌ) is followed by another letter, one of four tajweed rules applies, decided entirely by which letter comes next: Izhar (clear pronunciation), Idgham (merging), Iqlab (conversion to a meem sound), and Ikhfa (hiding with a nasal sound). Learn which letters trigger each rule and you have one of the most useful pieces of tajweed.
Noon sakinah is a noon with a sukoon (no vowel); tanween is the doubled-vowel ending that sounds like a noon sakinah. Both behave identically here, which is why the rules are taught together. Here they are, one by one.
1. Izhar (clear pronunciation)
If the noon sakinah or tanween is followed by one of the six throat letters — ء ه ع ح غ خ (hamza, haa, ‘ayn, Haa, ghayn, khaa) — you pronounce the noon clearly and distinctly, with no nasalisation held on it. This is called Izhar, meaning "to make clear." Example: مِنْ خَوْفٍ — the noon before خ is pronounced plainly.
2. Idgham (merging)
If the noon sakinah or tanween is followed by one of the six letters in the word يَرْمَلُون — ي ر م ل و ن — the noon merges into the following letter. Idgham splits into two kinds:
- Idgham with ghunnah — with the letters ي ن م و (grouped as يَنْمُو). The noon merges and a nasal sound (ghunnah) is held for about two counts. Example: مَنْ يَقُولُ.
- Idgham without ghunnah — with the two letters ل and ر. The noon merges fully into the next letter with no nasalisation. Example: مِنْ رَبِّهِمْ.
3. Iqlab (conversion)
If the noon sakinah or tanween is followed by a single letter, ب (baa), the noon is converted into a hidden meem sound, pronounced with ghunnah. This one rule has just one trigger letter, which makes it the easiest to remember. Example: مِنْ بَعْدِ is read as if "mim ba‘di."
4. Ikhfa (hiding)
If the noon sakinah or tanween is followed by any of the remaining fifteen letters (everything not covered above), the noon is neither pronounced clearly nor fully merged — it is "hidden," articulated as a light nasal sound that leans toward the next letter, held for about two counts. Ikhfa is the most common of the four rules simply because it covers the most letters. Example: مِنْ قَبْلِ.
The whole system comes down to one question: which letter follows the noon sakinah or tanween? Six throat letters → Izhar; يرملون → Idgham; ب → Iqlab; everything else → Ikhfa.
The meem sakinah rules (a close companion)
A meem sakinah (مْ) follows the same mental model with three rules, called the "shafawi" (lip) rules because meem is a lip letter:
- Ikhfa Shafawi — when meem sakinah is followed by ب, hide the meem with a light nasal sound.
- Idgham Shafawi — when followed by another م, merge the two with ghunnah.
- Izhar Shafawi — when followed by any other letter, pronounce the meem clearly.
Seeing and hearing the rules
These rules are far easier to internalise when you can see them in a real verse and hear them recited. RecitID’s Tajweed colour-coded Mushaf highlights pronunciation rules by colour as you read, and per-verse audio lets you hear a qualified reciter apply them. For the full colour legend and what each colour means, see our tajweed colour codes guide.
Frequently asked
What are the four rules of noon sakinah and tanween?
Izhar (clear pronunciation, with the six throat letters ء ه ع ح غ خ), Idgham (merging, with the letters of يرملون), Iqlab (converting the noon to a meem sound, with the letter ب), and Ikhfa (hiding with a nasal sound, with the remaining fifteen letters).
What is the difference between noon sakinah and tanween?
Noon sakinah is the letter noon carrying a sukoon (no vowel). Tanween is the doubled short-vowel ending at the end of a word, which is pronounced like a noon sakinah. Because they sound the same, the same four rules apply to both.
Which rule is the most common?
Ikhfa, because it applies to the largest group of letters — the fifteen not covered by Izhar, Idgham or Iqlab. This is why hearing a light, held nasal sound before many letters is so frequent in recitation.
Want to see these rules colour-coded as you read? Download RecitID for iOS and Android — the Tajweed Mushaf highlights the rules and lets you hear each one recited.