Why a 100W multi-port charger may not give your laptop 100W
The large number printed on a multi-port charger is often the total power budget, not a promise that every port can deliver that amount simultaneously.
Total power vs. per-port power
A 100W charger might offer up to 100W on one USB-C port when used alone, then redistribute power when a phone is connected to another port. The exact split depends on the charger's design.
Why charging can suddenly reconnect
Some chargers renegotiate USB-PD profiles when a new device is plugged in. That can cause a brief disconnect and a new power allocation. It is normal for many multi-port designs.
How WattageFit models it
Enter the charger's total rating, the maximum rating of the port you are using, and the expected load of other connected devices. The calculator subtracts shared load before comparing the remaining budget with the port, cable and device limits.
This is a model, not a live USB-PD analyzer. Real power-allocation tables are charger-specific, so the charger's own manual remains the best source for exact port combinations.
Reviewed September 12, 2026. This guide explains power compatibility, not electrical repair or modification.