# Can I find run time of a refrigerator given the Watt Hours?

I took the following measurements on my mini fridge with a power meter.

Voltage: 123 V
Current: 0.71 A
Power: 50 W

I ran for 4.75 hours and the meter read 52 Watts used. So I know that the watt hour rating is about 11Wh per hour (54W/4.75Hr).

Can I then conclude, since the wattage during on-cycle is 50 watts (and thus if ran for a complete hour would be 50 watt hours), that run time per hour would be 11Wh/50W = 22% of 50Wh

Then: 22% of an hour would be 13.2 minutes of actual run time.

The math seems to make sense to me but I can't find any examples on the internet.

• and the meter read 52 Watts used Watts is Joules (unit of energy) per second. So you cannot say about 11 watts per hour. To get the amount of energy (in Joules) you need to multiply Watts x time (in seconds). Instead of looking for examples on the Internet, try to understand how energy calculations work. It is not difficult. Real engineers ALWAYS check if the units make sense, if they do not the calculation is WRONG. Mar 30, 2017 at 14:01
• Out of curiosity, what stops you from dividing that 11 "Watts per hour" by 4.75 again to get 2.3 Watts per hour per hour? Mar 30, 2017 at 14:52
• @DmitryGrigoryev Power acceleration! Mar 30, 2017 at 14:57
• Possible duplicate of Are watts usually measured in watt-hours? Mar 30, 2017 at 15:03