Elétrica
Watts, ampere e tensão
W = V x A
W
Utilities
Electrical
watts, amps and voltage
Apply Ohm's Law to calculate power (watts) from voltage and current, find the current (amps) from power and voltage, and estimate monthly energy consumption in kWh and in your currency. Useful for electricians, students, and understanding the power consumption of any device.
How to use
- 1In 'Electrical power', enter the voltage (V) and the current (A) to find the power in watts (W = V × A).
- 2In 'Current', enter the wattage and the voltage to calculate the current in amps (A = W ÷ V).
- 3In 'Monthly consumption', enter the appliance's wattage, hours of use per day, days in the month, and the rate per kWh to estimate the monthly consumption and cost.
- 4Each calculator's result appears automatically as you fill in its fields.
Practical examples
A 120V electric shower drawing 10A
In 'Electrical power', the result is 1,200 W of instantaneous consumption.
A 1,500 W appliance plugged into a 240V outlet
In 'Current', the result is about 6.25 A drawn by the appliance.
A 1,000 W lamp used 2 hours a day, 30 days, at $0.15/kWh
In 'Monthly consumption', the result is 60 kWh, costing about $9.00 for the month.
Frequently asked questions
What is Ohm's Law?
Ohm's Law states that voltage (V) equals current (I) multiplied by resistance (R): V = I × R. All electrical power formulas are derived from this relationship.
How do I calculate the wattage of an appliance?
Enter the outlet voltage (e.g., 120V or 240V) and the appliance's current in amps (usually shown on the label). The calculator shows the power in watts.
Does it work for both AC and DC?
The basic calculations apply to both. For three-phase AC or circuits with a power factor, the formula is more complex.