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Electrical Calculators

From home energy bills to solar savings and EV charging times — our free electrical calculators handle the numbers so you don't have to.

Popular in Electrical

Electricity Bill Calculator Generator Size Calculator Solar Panel Calculator EV Charging Time Calculator Battery Life Calculator Amps to Watts Converter

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Home Energy

Calculate solar savings, electricity costs, and EV charging times

Circuit Basics

Ohm's Law, watts, voltage, and resistors

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Showing 59 of 59 calculators

Amps to Watts Converter

Convert amps to watts using voltage — P = I × V

Antenna Gain Calculator

Antenna Gain Calculator

Battery Bank / Capacity Calculator

Battery Bank / Capacity Calculator

Battery Life Calculator

Estimate how long your battery will last based on capacity and draw

Capacitive Reactance Calculator

Capacitive Reactance Calculator

Capacitor Calculator

Capacitor Calculator

Capacitor Charge & Energy Calculator

Capacitor Charge & Energy Calculator

Capacitors in Parallel Calculator

Capacitors in Parallel Calculator

Capacitors in Series Calculator

Capacitors in Series Calculator

Circuit Breaker Size Calculator

Circuit Breaker Size Calculator

Current Calculator

Current Calculator

Current Divider Calculator

Current Divider Calculator

Decibel Calculator

Decibel Calculator

Electricity Bill Calculator

Estimate appliance energy use, electricity cost, or household utility spend

EV Charging Time Calculator

Estimate how long it takes to charge your electric vehicle

EV Charging Time Calculator

EV Charging Time Calculator

Frequency to Wavelength Converter

Frequency to Wavelength Converter

Generator Size Calculator

Plan household, garden, utility, or energy projects

Impedance Calculator

Impedance Calculator

Inductive Reactance Calculator

Inductive Reactance Calculator

Inductor Calculator

Inductor Calculator

Kirchhoff's Law Calculator

Kirchhoff's Law Calculator

kW to kVA Converter

kW to kVA Converter

LED Resistor Calculator

Find the correct resistor for your LED circuit

LED vs CFL vs Incandescent Savings

LED vs CFL vs Incandescent Savings

Lumens to Watts Converter

Lumens to Watts Converter

Lux to Lumens Calculator

Lux to Lumens Calculator

Motor Power Calculator

Motor Power Calculator

Noise Figure Calculator

Noise Figure Calculator

NTC Thermistor Calculator

NTC Thermistor Calculator

Ohm's Law Calculator

Calculate voltage, current, or resistance using Ohm's Law (V = IR)

Op-Amp Gain Calculator

Op-Amp Gain Calculator

PCB Trace Width Calculator

PCB Trace Width Calculator

Power Factor Calculator

Power Factor Calculator

Power Factor Correction Calculator

Power Factor Correction Calculator

Pull-Up Resistor Calculator

Pull-Up Resistor Calculator

PWM Duty Cycle Calculator

PWM Duty Cycle Calculator

RC Time Constant Calculator

RC Time Constant Calculator

Resistor Calculator

Calculate resistor values, colour codes, and tolerance

Resistors in Parallel Calculator

Resistors in Parallel Calculator

Resistors in Series Calculator

Resistors in Series Calculator

RL Time Constant Calculator

RL Time Constant Calculator

RLC Resonance Frequency Calculator

RLC Resonance Frequency Calculator

Room Lighting Calculator

Room Lighting Calculator

Solar Panel Calculator

Calculate how many solar panels you need and estimate annual savings

Solar Panel Output Calculator

Solar Panel Output Calculator

Three-Phase Power Calculator

Three-Phase Power Calculator

Transformer Turns Ratio Calculator

Transformer Turns Ratio Calculator

Transistor Base Resistor Calculator

Transistor Base Resistor Calculator

Voltage Calculator

Calculate voltage from current and resistance

Voltage Divider Calculator

Voltage Divider Calculator

Voltage Drop Calculator

Voltage Drop Calculator

Voltage Regulator Calculator

Voltage Regulator Calculator

Volts to Watts Converter

Volts to Watts Converter

Watts Calculator

Calculate electrical power in watts from voltage and current

Watts to Amps Converter

Watts to Amps Converter

Wheatstone Bridge Calculator

Wheatstone Bridge Calculator

Wire Gauge Calculator

Wire Gauge Calculator

Electrical Glossary — Key Terms Explained

Watt (W): The unit of electrical power. Power = Voltage × Current (P = VI).
Ampere (A): The unit of electrical current — the rate at which charge flows through a circuit.
Volt (V): The unit of electrical potential difference (voltage) — the force that drives current through a circuit.
Ohm (Ω): The unit of electrical resistance. Defined by Ohm's Law: R = V/I.
kWh: Kilowatt-hour — the standard unit for measuring electricity consumption. 1 kWh = using 1,000 watts for 1 hour.

Frequently Asked Questions

How do I calculate my electricity bill?

Multiply the wattage of each appliance by the hours used per day, divide by 1,000 to get kWh, then multiply by your unit rate (p/kWh or ¢/kWh). Our Electricity Cost Calculator does this automatically.

How many solar panels do I need for my home?

A typical UK home uses 3,100 kWh per year and needs 6–10 panels. A US home averages 10,500 kWh and needs 20–25 panels. The exact number depends on panel wattage, roof orientation, and your local sun hours.

How long does it take to charge an EV?

It depends on the charger type and battery size. A 7kW home charger adds roughly 30–40 miles per hour. A 22kW charger triples that. A 150kW rapid charger can add 100 miles in 20 minutes.

What is Ohm's Law?

Ohm's Law states that Voltage (V) = Current (I) × Resistance (R). It describes the relationship between three fundamental electrical quantities and is the foundation of circuit analysis.