How to convert watts to joules
You can calculate joules from watts and seconds, but you can't convert watts to joules since watt and joule units represent different quantities.
Watts to joules calculation formula
The energy E in joules (J) is equal to the power P in watts (W), times the time period t in seconds (s):
E(J) = P(W) × t(s)
joules = watts × seconds
J = W × s
What is the energy consumption of an electrical circuit that has power consumption of 30 watts for time duration of 3 seconds?
E(J) = 30W × 3s = 90J