Watts to Amps Calculator — Power to Current (DC)
Quickly find how many amps a device draws: enter its wattage and the supply voltage. Uses the DC formula I = P ÷ V (for AC with power factor, see the wattage-to-amperage calculator).
W
V
Amperes (A) — calculated as Watts ÷ Volts
- 1
Power P
60From P = V × I rearranged: I = P ÷ V. - 2
Current I = P ÷ V
60 ÷ 120 = 0.5000
How does this calculator work?
Amps = Watts ÷ Volts (I = P / V). Enter wattage and voltage to instantly get the DC current draw and the equivalent resistance. For AC circuits with a power factor below 1, the wattage-to-amperage calculator gives a more accurate result.
Formula
How this is calculated
For a direct-current (DC) circuit, the relationship between power, voltage, and current is P = V × I, which rearranges to I = P / V. This is the fastest way to find amperage when you know an appliance's wattage and supply voltage.
The calculator also shows the equivalent resistance R = V / I = V² / P — the resistance a purely ohmic load would need to draw exactly that much power at that voltage. This is useful for checking resistor ratings or heating element design.
This formula is exact for DC and for AC circuits where the power factor is 1 (resistive loads such as heaters, toasters, and incandescent bulbs). For AC loads with reactive components (motors, LED drivers, transformers), the actual current is higher: I = P / (V × PF). Use the wattage-to-amperage calculator if you need to account for power factor.
Frequently asked questions
I = 100 W / 120 V ≈ 0.833 A. On 240 V it would only draw ≈ 0.417 A.
Only for resistive AC loads (heaters, incandescent bulbs, most simple heating elements) where the power factor is 1. For motors, LED drivers, and other reactive loads, divide by the power factor as well: I = P / (V × PF).
It is the resistance a purely ohmic device would need to consume that wattage at that voltage. Calculated as R = V² / P. It is not the internal resistance of real devices, which often change with temperature and operating conditions.
Also known as
TG we-Calculate Editorial Team. (2026). Watts to Amps Calculator — Power to Current (DC) [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/watts-to-amps-calculator
TG we-Calculate Editorial Team. "Watts to Amps Calculator — Power to Current (DC)." TG we-Calculate. 2026. https://we-calculate.com/calculator/watts-to-amps-calculator.
TG we-Calculate Editorial Team, "Watts to Amps Calculator — Power to Current (DC)," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/watts-to-amps-calculator
@misc{wecalculate_watts_to_amps_calculator, title = {Watts to Amps Calculator — Power to Current (DC)}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/watts-to-amps-calculator}}, year = {2026}, note = {TG we-Calculate} }
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