Hi

If you put the start date required in C1 and the end date in D1, then
enter in E1
=SUMPRODUCT((A1:A1000=C1)*(A1:A1000<=D1)*(B1:B100 0))/((D1-C1+1)*16)
Format E1 as Percentage
--
Regards

Roger Govier


"
ft.com wrote in
message ...
I am not familiar with the A:A, B:B notation. Is this an array form?
Can I
look into a date in mid cycle to get the cummulative total to date?

"vezerid" wrote:

Hi,

If column A:A contains dates and column B:B contains uptime then

=AVERAGE(B:B)/16

should give you the uptime percentage, if you format the cell as %.
It
will be dynamic, as it will change as more values are entered in B:B.
This will give you the total uptime since you started monitoring, so
naturally with time it should converge to your overall average.

Write back if you want something more specific, e.g. the average of
the
last X days.

HTH
Kostis Vezerides