Electricity
Watts, amps & volts calculator
Know two of watts, amps, volts or ohms? Get the rest, with Ohm’s law worked out step by step.
Power: 1,800 W
Electricity cost calculator
What an appliance costs to run per day, month and year, from its watts, the hours you use it and your price per kWh.
Per month: $32.85
Data
Electronics
Voltage divider calculator
Output voltage of two resistors in series, or the second resistor needed for a target voltage.
Output voltage: 3.837 V
Series & parallel calculator
Total resistance, capacitance or inductance of components in series or in parallel.
In series: 650
LED resistor calculator
The current-limiting resistor for one LED or several in series, with the next standard value and the power rating to buy.
Standard resistor (E24, next up): 150 Ω
Resistor color code calculator
Read a 4- or 5-band resistor: pick the colors to get the resistance, tolerance and range.
Resistance: 4.7 kΩ
RC time constant calculator
How fast a capacitor charges through a resistor, the RC filter’s cutoff frequency, and the charge reached after any time.
Time constant τ: 1 s
Wire voltage drop calculator
Voltage lost in a copper or aluminum wire run by AWG size, length and current, with the voltage left at the load.
Voltage drop: 5.79 V