I think I misunderstood what you're looking for.
The formula I posted calculates the maximum consecutive occurrences of zero.
Not the count of consecutive zeros AFTER the last 1.
Bernd P seems to have gotten it right.

Regards,

Ron Coderre
Microsoft MVP (Excel)

"Ron Coderre" wrote in message
...
With possible values in A2:A30

This ARRAY FORMULA, committed with CTRL+SHIFT+ENTER
(instead of just ENTER) returns the maximum consecutive occurrences of
zero.
C1: =MAX(FREQUENCY(IF((A2:A30<"")*(A2:A30=0),ROW(A2:A 30)),
IF(A2:A30<0,ROW(A2:A30))))

Is that something you can work with?

Regards,

Ron Coderre
Microsoft MVP (Excel)

"Samuel" wrote in message
...
Hiya,

I am currently trying to calculate the largest gap in a series of numbers
where a particular number has not appeared and display this number in a
cell.

For example,

There are 2 numbers involved, 0 and 1. My spreadsheet looks like:

A1
A2 1
A3 0
A4 0
A5 0
A6 0
A7 1
A8 0
A9 0 and so on.....

Now, in cell C1 I want excel to automatically calculate the number of
times
0 has come up consecutively up to the last time the number 1 appeared. So
when inputting data downwards in A10, A11, A12 it will be able to tell me
how
many consecutive 0's there have been until the last number 1 appeared.

In the above example, if I had input the data upto A5, C1 would display
the
number 3 (there have been three 0's since the last 1 came up). When A6 is
filled in with a 0, C1 would display 4, yet once A7 had been filled in
the
counter would reset back to 0 in C1.

I have tried to explain this as best as I can, if you need any
clarification
please ask, and thank you kindly in advance,