Noon Sakinah Rules Explained: Izhar, Idgham, Iqlab and Ikhfa
When a still Noon — a Noon with no vowel, called Noon Sakinah — or a Tanween meets the next letter, one of four things happens: it is pronounced clearly (Izhar), merged into the next letter (Idgham), turned into a Meem sound (Iqlab), or hidden with a nasal sound (Ikhfa). The next letter decides which one, and that single idea is the key to all four rules.
AT A GLANCE
Key takeaways
- A still Noon (Noon Sakinah) and Tanween follow the same four rules, because Tanween sounds like a hidden Noon.
- There are four rules: Izhar (clear), Idgham (merging), Iqlab (turning into Meem), and Ikhfa (hiding with a nasal sound).
- The letter after the Noon decides which rule applies — so the skill is looking ahead before you read.
- Learn one rule at a time, and practise it until it is automatic before moving to the next.
The four rules and what triggers each
A Noon Sakinah is a Noon letter with no vowel on it — a still Noon. Tanween, the doubled vowel at the end of a word, behaves the same way in Tajweed, because the “n” sound at the end of a Tanween is really the sound of a hidden Noon. So the rules in this article apply to both: to a still Noon, and to a Tanween.
Whenever a still Noon or a Tanween meets the letter after it, one of four things happens. If the next letter is one of the six throat letters, the Noon is pronounced clearly — this is Izhar. If the next letter is one of the six merging letters, the Noon melts into it — this is Idgham. If the next letter is Ba, the Noon turns into a Meem sound — this is Iqlab. And if the next letter is one of the fifteen remaining letters, the Noon is hidden with a nasal sound — this is Ikhfa.
That is the whole system in one paragraph, and it is worth reading twice, because everything that follows is detail on those four lines.
Izhar: the six throat letters — pronounce clearly
Izhar means to make clear, and it is the simplest of the four rules. When a still Noon or a Tanween is followed by one of the six throat letters, the Noon is pronounced clearly, exactly as it is, with no merging, no hiding, and no nasal sound added. You say the “n” plainly, and then you say the throat letter.
The six letters that cause Izhar are the six throat letters — the same six covered in the article on throat letters, from the bottom, middle and top of the throat. The reason they cause a clear pronunciation is a practical one: the throat letters are made far from where the Noon is made, so the two sounds do not blend into each other. The Noon comes out clearly, and the throat letter follows clearly, and neither one changes the other.
Idgham: the six merging letters
Idgham means merging, and it is the rule where the Noon disappears into the letter after it. When a still Noon or a Tanween is followed by one of the six merging letters, the Noon melts into that letter, so the two sounds become one. You do not say a separate “n” and then the next letter — you say the next letter, with the Noon folded into it.
The six merging letters form a group of their own, and the merge works differently depending on which of them follows. With four of the six letters, the merge carries a nasal sound — a light hum through the nose that lasts for about two counts. With the other two, the merge has no nasal sound at all: the Noon simply disappears into the next letter, cleanly and completely. Your teacher will show you which letters carry the nasal sound and which do not, and the difference is easy to hear once it has been demonstrated.
Iqlab: the one letter, Ba
Iqlab is the smallest of the four rules, and the easiest to learn, because it has only one trigger letter: Ba. When a still Noon or a Tanween is followed by Ba, the Noon sound turns into a Meem sound, held with a nasal tone for about two counts. That is the whole rule — one letter, one change.
In the Mushaf, Iqlab is marked for you. Where a still Noon or a Tanween is followed by Ba, a small Meem mark is written to show that the sound has changed. That mark is your signal: when you see it, you know the Noon has become a Meem, and you read it that way. The most common mistake is missing the mark and reading a plain “n” before the Ba. The fix is to watch for the small Meem mark while you read, and to let it remind you that the sound has changed. Because there is only one letter to watch for, Iqlab is often the first of the four rules that learners master completely.
Ikhfa: the fifteen hiding letters
Ikhfa means hiding, and it is the rule that applies most often, because it covers the largest group: fifteen letters. When a still Noon or a Tanween is followed by one of the fifteen hiding letters, the Noon is hidden — not pronounced clearly, and not merged completely, but held back with a light nasal sound for about two counts.
Because Ikhfa covers fifteen letters, it is the rule you will meet most often while reading, which is why it is given its own full article. The fifteen letters are the ones that remain once the other three groups are set aside: not throat letters, not merging letters, and not Ba. Your teacher will show you the group, and you will learn to recognise its members as you read.
A practice table and how to drill one rule at a time
The four rules are easier to remember as a small table. Keep it beside you while you practise, and use it to check yourself until the rules are automatic.
| Rule | What triggers it | What happens to the Noon |
|---|---|---|
| Izhar | One of the six throat letters follows | Pronounced clearly, exactly as it is |
| Idgham | One of the six merging letters follows | Merged into the next letter |
| Iqlab | The letter Ba follows | Turned into a Meem sound, held with a nasal tone |
| Ikhfa | One of the fifteen hiding letters follows | Hidden with a light nasal sound, held for about two counts |
The way to drill the rules is one at a time, and that order matters. Start with Izhar, because it is the simplest — the Noon is read clearly, and there is nothing extra to learn. Practise it for a few days, reading short passages and marking every still Noon and Tanween that is followed by a throat letter, until spotting them becomes automatic. Then move to Iqlab, because it has only one trigger letter, and the small Meem mark in the Mushaf helps you find it. Then Idgham, with its merge, and finally Ikhfa, which covers the most letters and takes the longest to master.
Yasir Qadhi’s approach to learning fits this way of working: deep, structured study, built on classical training from Madinah along with a PhD from Yale, with the idea that serious study starts with the Quran itself. The four rules are a good example of that structure — a small, complete system, learned rule by rule, from the text itself, until the whole system is in place.
Keep each drill short, about five to ten minutes, and always read aloud. The four rules are sound rules, and they are learned by hearing and saying, not by reading about them. A few weeks of one-rule-at-a-time practice, with a teacher listening, is enough for most learners to start applying the rules while they read — and once they are applied while reading, they become part of how you recite, not something you have to think about.
✅ Checklist — the Noon Sakinah rules
- ✔ Learn the four rules as one system: Izhar, Idgham, Iqlab and Ikhfa.
- ✔ Always look at the letter after the Noon before deciding which rule applies.
- ✔ Read the Noon clearly when a throat letter follows — that is Izhar.
- ✔ Let the Noon melt into the next letter when a merging letter follows — that is Idgham.
- ✔ Turn the Noon into a Meem sound when Ba follows, and watch for the small Meem mark — that is Iqlab.
- ✔ Hide the Noon with a light nasal sound, held for about two counts, when a hiding letter follows — that is Ikhfa.
- ✔ Drill one rule at a time, starting with Izhar, and do not move on until it is automatic.
Frequently Asked Questions
What are the rules of Noon Sakinah?
There are four rules, and the letter after the Noon decides which one applies. Izhar means the Noon is pronounced clearly, Idgham means it is merged into the next letter, Iqlab means it turns into a Meem sound, and Ikhfa means it is hidden with a nasal sound. The same four rules apply to Tanween, because Tanween sounds like a hidden Noon.
How many Noon Sakinah rules are there?
There are four Noon Sakinah rules: Izhar, Idgham, Iqlab and Ikhfa. Together they cover every letter of the alphabet — six letters for Izhar, six for Idgham, one for Iqlab, and fifteen for Ikhfa — so whenever a still Noon or a Tanween meets the next letter, exactly one rule applies.
What is the difference between Idgham and Ikhfa?
In Idgham, the Noon merges completely into the next letter, so the two sounds become one and no separate Noon is heard. In Ikhfa, the Noon is hidden rather than merged: it is held back with a light nasal sound for about two counts, and the tongue moves towards the next letter without quite reaching it. Idgham is a full merge; Ikhfa is a hiding.
Which letters cause Izhar?
The six throat letters cause Izhar — the same six letters covered in the article on throat letters, from the bottom, middle and top of the throat. When a still Noon or a Tanween is followed by one of these six letters, the Noon is pronounced clearly, with no merging, no hiding, and no nasal sound added.
What is Iqlab?
Iqlab happens only before the letter Ba: the Noon sound turns into a Meem sound, held with a nasal tone for about two counts. It is the smallest of the four rules, with only one trigger letter, and in the Mushaf it is marked with a small Meem sign so you can spot it while reading.
How do I remember the four rules?
Learn them one at a time, starting with Izhar, and use a small table: throat letters mean clear, merging letters mean merge, Ba means turn into Meem, and hiding letters mean hide with a nasal sound. Drill one rule in short passages until it is automatic before moving to the next, and always look at the letter after the Noon before deciding.
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