Please find below the formula in computing your estimated monthly payable  for a certain appliance.

Wattage  x  No. of hours Used x No. of Days Used / 1000 = Estimated kWhr Consumption x Rate = Estimated Amount Payable

For example, if your using an Electric iron for 3 hours a day for 30days,
your estimated monthly bill is Php 924.75.
Computation is as follows:

Wattage   ---------------- >  750W
No. of hours used    ------>  3 hrs
No. of days used     ------>  30days
Rate    ---------------------> Php 13.70per kwhr

750W x 3hrs x 30days / 1000 = 67.5 kWhrs x 13.70 = Php 924.75 -------> Estimated Monthly Payable for 1 electric iron