Time calulations

[Hydro]

I am trying to compute the downtime and have a formula that subtracts the on task time, transit and wait time from 24 hours. However if the sum of the calculation equals 24 hours then I get #####s in the cell; if it equals 00:00:01 then it will display correctly ie 00:00. Is there a way of showing zero downtime as 00:00 when the calculation returns a value of 00:00:00. I have tried different formats of the results cell (hh;mm and [h]:mm) but it makes no difference.
Help appreciated

 

[joeu2004]

if the sum of the calculation equals 24 hours then I get #####s in the cell; if it equals 00:00:01 then it will display correctly ie 00:00. Is there a way of showing zero downtime as 00:00 when the calculation returns a value of 00:00:00.

It is difficult to say for sure without a concrete example that demonstrates the problem.

I suspect the problem is the result of anomalies with 64-bit binary floating-point values, which is how Excel represents numbers internally, including time. The result of your time arithmetic might be infinitesimally less than zero. To confirm, temporarily format the cell as Scientific. You might see a result of the form -1.23E-14.

To avoid this, if your time formula is of the form =expression, change it to:

=ROUND((expression)*86400,0)/86400

formatted as Custom [h]:mm . That rounds to the second.

 

[Hydro]

Hi

many thanks for the reply. I tested as requested and got -8.9E13. used the round function and it no displays correctly ie 00:00.

much appreciated