### Time calculation - which formula is needed?

I sum up times and the sum goes beyond 24h and need to multiply the hours with an hourly rate to create an invoice.

- Until 23:59 I can use the formula
`=(HOUR(G15)+MINUTE(G15)/60)*320`

to linearize the time - Beyond 23:59 the used formula reduces the time value by 24h. This is the correct functionality of the HOUR(cell) function.

I searched Help and Help Wiki but it seems that I overlooked the solution.

I appreciate any help which ~~helps ~~lets me to linearize hours and minutes beyond 23:59.