Formula issues getting blank rather than zero

[Detectiveclem]

What am I doing wrong

I am using this formula in cell E7 successfully =IF(D7-C7<0, 1+D7-C7, D7-C7).

But when cell C7 has no data I do NOT want ‘0’ to appear in E7. I have tried various formulas including this one =IF(C7=””,””,D7-C7<0, 1+D7-C7, D7-C7) but it doesn’t work.

Can someone please help me rectify the formula so that cell E7 remains blank until data is entered in C7.

Thank you

 

[Fluff]

Oops, wasn't thinking. It should be
=IF(AND(M23="",O23=""),"",IF(M23="",-O23,M23-O23))

 

[Detectiveclem]

You are a genius, everything works perfectly. Sorry for taking up so much of your time but very much appreciated.

 

[Fluff]

Glad we could help & thanks for the feedback