🔌 Electrical Tools
Free calculators for electrical work, electronics, and circuit design. Compute voltage, current, resistance, wire sizes, and more.
Battery Life Calculator
Calculate how long a battery will last — enter mAh capacity and current draw, get runtime in hours and days with efficiency and discharge depth
Electricity Cost Calculator
Calculate how much it costs to run any appliance. Add multiple devices, set your electricity rate, and see daily, monthly, and yearly costs instantly.
LED Resistor Calculator
Calculate the resistor value for any LED — with standard E12/E24 rounding, color bands, power rating, and series LED support
Ohm's Law Calculator
Enter any two of Voltage, Current, Resistance, and Power — instantly get the other two. The essential electrical formula tool.
Resistor Color Code Calculator
Decode resistor color bands to value or find the right colors for any resistance — supports 4-band and 5-band resistors
Voltage Divider Calculator
Calculate output voltage from R1 and R2, or find the right resistor pair for a desired output — with schematic diagram and E24 suggestions
Wire Gauge Calculator
Find the right wire size for any circuit — enter amps, distance, and voltage to get AWG/mm² with voltage drop analysis