How much space does the ios 4.3 take over 4.2

[jedelaney01]

My daughter just bought a left over iPad first edition and I was telling her about the new OS 4.3. Much to my frustration, she is hesitant because she is concerned about the amount of space the update would take up on her 16GB SSD. I know when I updated my iPhone 4 to 4.3 it said the size of the update was 300+Mb. My question is: is this in addition to the the old 4.2 OS or does the update remove the old space taken up by the 4.2 and replace it with the new OS? I am flummoxed (as Steve Jobs would say) by her hesitation to improve what she just bought for no cost to her, she never listens to me

 

[JamesMB]

My question is: is this in addition to the the old 4.2 OS

No

or does the update remove the old space taken up by the 4.2 and replace it with the new OS?

Yes

 

[QuarterSwede]

I'm not sure what the uncompressed size is when installed but it's probably only slightly larger than 4.2. It's certainly no reason to not update.