Electrical boundaries
| Boundary | Tool interpretation |
|---|---|
| Up to 3 A | A 60 W cable class can cover a compliant point at 20 V or below. |
| More than 3 A, up to 5 A | A 5 A electronically marked C-to-C cable is required. |
| More than 20 V | The path requires USB PD Extended Power Range support. |
| Up to 240 W | Overall USB PD ceiling: 48 V × 5 A. |
Current USB-IF certified C-to-C power logos use 60 W or 240 W. Legacy 100 W / 5 A cable claims may remain valid for older products, but the new-cable selection tools recommend the current 240 W marking above 60 W.
PPS interpretation
The PPS checker treats one APDO as a rectangular voltage/current boundary plus any explicitly published power ceiling. It tests one requested point against one range. It does not assume that every certified charger includes PPS, and it does not infer the fallback rate when a match is absent.
Dock and hub budgeting
The hub calculator follows Microsoft’s public docking example structure: total supply must cover host delivery and each downstream allocation. A user-entered dock reserve keeps undocumented allocation visible instead of pretending it is a universal constant.
Primary sources
- USB-IF — USB Charger / Power DeliveryPublic overview of USB PD and charging up to 240 W.
- USB-IF — Cables and ConnectorsCurrent 60 W and 240 W certified cable power markings.
- USB-IF — Compliance updatesTransition from legacy 100 W branding and e-marker requirements.
- USB-IF — PPS certified fast charger announcementPublic explanation of Programmable Power Supply support.
- Microsoft Learn — DockingHost and downstream power-budget example plus dock capability requirements.
Tool policy
A matching calculation is labeled declared fit or range match. Only hardware or trusted system telemetry can observe the negotiated profile. No tool predicts battery taper, thermal limits, or a proprietary fallback wattage.