"Leah1668" wrote:
I need to convert 3 cells, one being DAYS,
the second Hours, and the third MINS into
a 4th cell which needs to be a decimal.

Decimal what?!

If decimal days, try:

=A1+TIME(B1,C1,0)
or
=A1 + B1/24 + C1/1440

formatted as Number, where A1 is days, B1 is hour, and C1 is minutes.

If decimal hours, try:

=(A1+TIME(B1,C1,0))*24
or
=A1*24 + B1 + C1/60

If decimal minutes, try:

=(A1+TIME(B1,C1,0))*1440
or
=A1*1440 + B1*60 + C1

The multipliers are derived from the fact that Excel time is represented as
a fraction of a day. There are 24 hours or 1440 (24*60) minutes in a day.