How to round (up) a number to nearest power of 2?

[laurcoman]

Hi,

I need to round up the numbers from a column to their nearest power of 2 number (eg: 13 round to 16; 17 round to 32; 100 round to 128 etc).

I can't find a formula to make this rounding.

Is there anybody who can help me?

Thanks!

 

[PaddyD]

hi - welcome to the board!

what I'd do:

1) set up an appropriately constructed lookup table that covers the number range you're likely to have to deal with
2) use a lookup formula to return the "rounded" number

...need anything more explicit?

 

[Fergus]

For example in A1 put in =2 ^ROW() and drag it down as far as necessary, then assuming the number you want to round up is in B1 use the formula =LOOKUP(B1,A1:A30)*2

 

[barry houdini]

This is a question I asked on here some time ago....try

=2^ROUNDUP(LOG(A1,2),0)

where your number is in A1

 

[Fergus]

My, that's clever Barry

 

[barry houdini]

I should say that that solution was provided for me by Yogi Anand

 

[laurcoman]

Thanks.

Yes, please give me more details - I didn't work with lookup formula.

 

[laurcoman]

Thank you very much for all of your answers.
The Barry's formula is great, it is exactly what I need.

 

[rambouno100]

This is a question I asked on here some time ago....try

=2^ROUNDUP(LOG(A1,2),0)

where your number is in A1

Thanks, you are a ****ing CRACK!!