formula to convert null to zero

[islandtime]

 I have created a custom column that subtracts two dates (Completed Date - Due Date), to give a whole number. 

I would also like to add to this custom colum a conversion that changes all the negative numbers to zero, i.e. everything appears as a zero unless the item was completed past its due date. 

Can anyone give some pointers on how I might achieve this?

[Interkoubess · Accepted solution]

Hi @islandtime,

Please try this formula :

=if (Due Date>Completed Date ,0,Completed Date -Due Date)

Hope it helps...

Ninter