Laptop Charging Time Calculator
Enter the battery capacity, the charger's wattage and the most the laptop accepts. The tool estimates the time for the charge range you pick.
How it works
Energy needed is the battery capacity times the share you want to add. Charging power is the lower of the charger's wattage and what the laptop accepts, reduced by the efficiency figure to cover losses as heat.
Charging slows down near full, so the last 20% takes longer than this simple estimate. Using the laptop while it charges also takes power away from the battery.
Questions and answers
Will a bigger charger charge my laptop faster?
Only up to the power the laptop accepts. A 100 W charger on a laptop that takes 45 W still charges at 45 W.
Can I use a smaller USB-C charger?
Usually yes, but it charges slowly, and under heavy load the battery may still drain while plugged in.
Why does charging slow down after 80%?
Lithium-ion batteries are charged at a lower current near full to protect the cells.