What is difference between 4A, 3NG, 5I, 4S etc... ?

Hello

Can someone explain to me the difference between different categories of HDB flats. I do understand the number of rooms part, but whats the meaning of NG, S, A , A1, I etc suffixes.

I couldnt find any information on HDB website explaining the difference.
Would someone be kind enough to explain it here. Would really help me in my house search

Thank You

as far as i know.

ng stands for new generation
s for simplified
a for advanced
I for improved

hope this will help you

is there any difference to the square metre area. Example 4 room?

For 4 room, as far as i know

4A area will be around 100sqm
4NG will be 90 and above
4s will be 85 which is the smallest

Does it also say anything about the number of toilets in the flat?

Like there are some 3 room flats with 2 toilets.
Which category is that?

Here U go ....

a) 3A Sq ft: 75
b) 3A(mod) Sq ft: 90
c) 3I Sq ft: 60.30 (No attached bath. Toilet and bath separated. No storeroom.)
d) 3I(mod) Sq ft: 69.60
e) 3NG Sq ft: 68.80
f) 3NG(mod) Sq ft: 83.20
g) 3S Sq ft: 65
h) 3Std Sq ft: 54.10 (No attached bath/storeroom.)
i) 4A Sq ft: 105
j) 4I Sq ft: 83.50 (No attached bath. Toilet and bath separated. No storeroom. )
k) 4S Sq ft: 85
l) 4NG Sq ft: 92
m) 4Std Sq ft: 72.50 (No attached bath/storeroom.)
n) 5A Sq ft: 135
o) 5I Sq ft: 124
p) 5S Sq ft: 120
q) Exec Apt Sq ft: 145 (Single level)
r) Exec Mais Sq ft: 145 (Double level)

excellent.

THANKS

i believe he meant sqm, not sqft

Anyone care to post some of the flats layout? eg. how does a 4S flat layout look like?

Yes, it is SQM.

Please note that the size mentioned here is for guidance only. Size are around that but lots depends on area. For example, Pasir Ris 4A can be as big as 110SQM, where as Seng Kang 4A can be as small as 85 SQM. There are 4A in Hougang and Lor Ah Soo that are as big as 120SQM.
For example, Punggol 5I are just 110 SQM, same size as Pasir Ris 4A....

In general, for a particular area and built year this is the descending order

A >> NG >> I >> S >> Std

In general older flats are bigger than newer flats