Answer:
All household bulbs run on 120 volts.
Of course, "WATTS" is a product of the voltage and the amperage. So, while normal household current is powered by 120 volts AC, you may find that some of the off-road vehicles (with the lights mounted on the upper roll bar) may actually have lights that are rated at higher wattage than that, even though they are powered by 13.7 volts DC from the vehicle's electrical system.
The formula is W=E X I. Where "W" is the wattage, "E" is the voltage (electromotive force), and "I" is the amperage. So, using that formula, a 40 watt bulb lit by 120 volt house current would draw .333 amps, or a third of an amp.
But, a 40 watt bulb powered by a vehicle's electrical system would draw 2.919 amps.
There are also industrial application bulbs that operate on 230 volts, but with each level of voltage, the "base" is different, so that one voltage rating can not readily be inserted in another voltage application.