thatt all depends on what type and size fridge fan and laptop charger...
all of those loads could be native 12v dc if you wanted and could get away with no inverter. if you have an unmodified dorm fridge a standard wall plug laptop charger and 110 lights a good 1000 watt invert er could be ok. if you have a sufficient battery bank.
in one of my rigs, a short bus. i have a 12 volts fridge/freezer and all migh lighting is 12 volt. i do have a 135 watt high quality inverter and only use it for a regular wall plug laptop charger and charging cordless drill/saw
in my other rig i have a 3.1 cubic foot dorm type fridge/freezer cordless tool charging and laptop charging and i get by with a 375 watt quality inverter, but if the fridge cycles while the chasrger is pulling good, it will fault out. then i have to unplug everything but fridge, get fridge started and then plug the other stuff back in.
the fridge would not start on the 375 watt inverter till i installed a "hard start kit"
just a few examples for you
oh, i am currently fond of the victron phoenix inverters pure sine wave