Power Consumption Calculator
Calculate how much electricity a device uses and what it costs to run. Enter the device's wattage, how many hours a day it runs, and your electricity rate for an instant cost breakdown.
Recommended Settings
Pro Tips
- •A device's wattage is usually printed on its label, power adapter, or in its spec sheet - use the actual rated wattage, not an estimate, for the most accurate cost
- •The default electricity rate (16 cents per kWh) is a rough US average - check a recent utility bill for your actual rate, since it varies significantly by region
- •Devices that run continuously (like a router, network dish, or server) use far more energy over a year than their wattage alone suggests - the hours-per-day multiplier matters a lot
- •This estimates steady-state power draw - devices with variable power use (like most electronics that idle lower than peak) will use somewhat less than this estimate
Most Popular
Most users check the running cost of an always-on device like a router, modem, or network equipment by entering 24 hours per day
When to Use This Tool
Find out how much it costs to run a specific device continuously, like a router, modem, or satellite dish.
Compare the running cost of two devices with different wattages before buying.
Estimate the monthly or yearly electricity cost of equipment that stays powered on around the clock.
Estimate the cost of a device's standby or idle power draw over a full year.
How It Works
Multiply the device's wattage by hours used per day, then divide by 1,000 to get daily energy use in kilowatt-hours (kWh)
Multiply daily kWh by 30 for a monthly estimate and by 365 for a yearly estimate
Multiply each usage figure by your electricity rate per kWh to calculate the estimated cost
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Client-side JavaScript arithmetic for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
Where do I find a device's wattage?
Check the label on the device itself, its power adapter, or the manufacturer's spec sheet - it's usually listed in watts (W). If only amps and volts are listed, multiply them together to estimate watts.
How do I find my electricity rate?
Check a recent electricity bill for your rate per kilowatt-hour (kWh), usually listed as cents or dollars per kWh. Rates vary significantly by region and utility provider.
Why does this ask for hours per day instead of just daily total?
Wattage combined with hours-of-use is how energy consumption is actually calculated (watts x hours = watt-hours), so this mirrors how utility companies and appliance labels express power usage.
Is this accurate for devices with variable power draw?
This calculates a steady-state estimate based on the wattage you enter. Many electronics draw less power when idle than at peak load, so actual usage may be somewhat lower than this estimate for devices that aren't constantly under full load.
Is my data sent to a server?
No. All calculations happen instantly in your browser using JavaScript.