What formula does this calculator use?

For DC or purely resistive AC loads: kWh = (V × I × t) / 1000. For AC loads with a power factor: kWh = (V × I × PF × t) / 1000. Here V is voltage in volts, I is current in amperes, PF is the power factor (0–1), and t is time in hours.

What is a kilowatt-hour?

A kilowatt-hour (kWh) is the energy consumed by a 1,000-watt load running for one hour. It is the standard unit used by utility companies to bill electricity and is commonly used to rate battery storage capacity.

What is the power factor and when do I need it?

The power factor (PF) represents the ratio of real power to apparent power in an AC circuit. Inductive loads such as motors and transformers have a PF less than 1. For DC circuits or purely resistive AC loads (heaters, incandescent bulbs), PF = 1 and you can leave the field blank.

How do I convert minutes or seconds to hours?

The calculator handles this automatically when you select the minutes or seconds time unit. If you want to convert manually: divide minutes by 60 (e.g., 90 minutes = 1.5 hours) or divide seconds by 3600.

How is this different from the Amps to kWh calculator?

Both tools compute the same kWh = (V × I × t) / 1000 formula. This tool emphasizes voltage as the starting point and adds a time-unit selector (hours/minutes/seconds) plus a power-factor field, making it useful for battery sizing and AC circuit analysis.

How many kWh does a 12 V, 50 A battery deliver in 2 hours?

kWh = (12 × 50 × 2) / 1000 = 1200 / 1000 = 1.2 kWh.

Volts to Kilowatt Hours Calculator

Enter voltage (V), current (A), and time to calculate electrical energy consumption in kilowatt-hours (kWh).

Input Values

Voltage (V)

Current (A)

Time

Power Factor optional, 0–1, for AC loads

Result

Enter values and press Calculate

Formulas

DC / Resistive AC

kWh = (V × A × h) / 1000

AC with Power Factor

kWh = (V × A × PF × h) / 1000

Intermediate — Power

W = V × A (× PF for AC)

Result copied!

Summary

This calculator converts voltage in volts (V) together with current in amperes (A) and a time duration into electrical energy measured in kilowatt-hours (kWh). The core formula is kWh = (V × I × t) / 1000, where t is time in hours. An optional power-factor field lets you model real AC loads accurately by computing kWh = (V × I × PF × t) / 1000. Kilowatt-hours are the standard billing unit for electricity and the common capacity unit for batteries and solar systems.

How it works

Enter the voltage in volts (V) — for example 120 V for a US household outlet or 12 V for a car battery.
Enter the current in amperes (A) drawn by the load.
Select a time unit (hours, minutes, or seconds) and enter the duration.
Optionally enter a power factor (0–1) for AC circuits with reactive loads; leave blank or set to 1 for DC or resistive loads.
Press Calculate to see energy in kilowatt-hours plus an intermediate breakdown of watts and watt-hours.
Press Reset to clear all fields for a new calculation.

Use cases

Calculate how many kWh a battery delivers given its rated voltage, discharge current, and runtime.
Estimate appliance electricity cost from its nameplate voltage and current rating.
Size a solar panel system by converting load voltage and current to daily kWh demand.
Compute EV charging energy from the charger voltage, charging current, and session length.
Verify electricity meter readings by computing expected kWh from circuit measurements.
Model generator fuel use by converting load voltage and current to energy drawn per hour.
Determine industrial motor running costs from its rated voltage, full-load current, and operating hours.
Convert battery specifications (V × Ah) directly to kWh for storage capacity planning.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu