Power Bank Charges Calculator
How many times a power bank will really charge your phone, using a realistic efficiency rather than the number printed…
Mobile & Electronics tools
Power banks, chargers, cables and batteries. Work out the capacity, wattage or runtime you actually need rather than the number on the box.
Electrical Power Calculator
Watts from volts and amps, in whatever units you have them - and the missing one when you have the other two.
Voltage, Current & Power Calculator
Enter any two of voltage, current and power and get the third, in whatever units you have them in.
Watt to Amp Calculator
How many amps a given wattage draws at a given voltage - the figure that decides whether a circuit copes.
Amp to Watt Calculator
Watts from amps and volts, handling milliamps - the conversion for turning a charger label into a wattage.
Volt to Watt Calculator
Volts alone cannot give watts. Here is why, and what to add to get the answer you are after.
Watt to Volt Calculator
The voltage a given wattage runs at, when you know the current.
Charger Power Calculator
What a charger actually puts out, from the volts and amps on its label - and whether that covers what you want to run.
USB Power Calculator
What a USB connection comes to in watts, and why that figure is a ceiling rather than a promise.
USB-C Power Calculator
What a USB-C link comes to in watts at a given voltage and current - without pretending to know which profile your…
Adapter Power Calculator
An adapter's maximum output in watts, from the voltage and current on its label.
Electrical Energy Calculator
Watt-hours and units from a power and a running time, in whatever units you have them.
Electricity Cost Calculator
What a device costs to run per day, month and year, at your own tariff rather than a national average.
Device Running Cost Calculator
What one appliance costs you a month, so you can decide whether to run it, replace it, or use it differently.
Multi-Device Electricity Cost Calculator
Several appliances costed together and ranked, so you can see which ones are actually responsible for the bill.
Laptop Power Cost Calculator
What your laptop costs to run a month - using its own power draw, not an assumed one.
Monitor Power Cost Calculator
What a monitor costs to run a month, from the wattage on its own label rather than a figure for its size.
mAh to Wh Calculator
Convert a battery's mAh into watt-hours - the figure that lets you compare two batteries honestly.
Wh to mAh Calculator
Convert watt-hours back into mAh at a stated voltage - the conversion for reading a laptop battery in phone-battery…
Ah to Wh Calculator
Amp-hours into watt-hours - the conversion for inverter, UPS and vehicle batteries, where Ah is the usual label.
Wh to Ah Calculator
Watt-hours into amp-hours at a chosen system voltage - for turning an energy requirement into a battery you can buy.
Battery Energy Calculator
What a battery holds and what you actually get out of it, with the conversion loss shown as its own line.
Power Bank Energy Calculator
What a power bank really delivers against the number on the case, and why the two are so far apart.
Power Bank Backup Calculator
How long a power bank runs a device, and how many charges it gives a phone whose battery you supply.
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