Decode your charger's power
Paste the OUTPUT line from the charger — 5V⎓3A / 9V⎓2A / 12V⎓1.5A — and learn instantly: 15W · 18W · 18W, 18W maximum. Not 51: alternative modes do not add up.
5V×3A + 9V×2A + 12V×1.5A = 15W · 18W · 18W → MAX 18W, not 51W.
Decoder
spaces, slashes or commas all work: 5V 3A, 5V/3A, 9V 2A. Voltage first, then current.
5V⎓3A15W / 9V⎓2A18W / 12V⎓1.5A18W
MAX18W
Not 51W: the 3 are alternative modes for one port, they do not add up.
Maximum power 18W, 3 profiles
Common profiles, worked out
The combinations seen most often on labels. Every row is voltage times current — nothing more.
| Profile | Power |
|---|---|
| 5V × 2A | 10W |
| 5V × 3A | 15W |
| 9V × 2A | 18W |
| 9V × 3A | 27W |
| 12V × 1.5A | 18W |
| 12V × 3A | 36W |
| 15V × 3A | 45W |
| 20V × 2.25A | 45W |
| 20V × 3.25A | 65W |
| 20V × 5A | 100W |
| 28V × 5A | 140W |
| 48V × 5A | 240W |
How to read a label
Every profile is one multiplication: watts = volts × amps. 9V × 2A means 18W, and 20V × 3.25A means 65W. The ⎓ symbol between them means direct current — same as a slash or a space.
Multiple profiles are alternative modes for one port: the charger delivers a single mode at a time, chosen together with the device. That is why the charger's power is the maximum, not the sum: 15W · 18W · 18W means an 18W charger, not a 51W one.
What actually flows is negotiated by three parties: charger, cable and device. An old phone on a new 65W brick takes what it knows — for example 10W — and at high power the cable matters too: the top USB-C ranges require marked cables. Ranges like 3.3-11V⎓3A are programmable bands: the maximum sits at the top voltage, 11 × 3 = 33W. Read the OUTPUT line, not INPUT: 100-240V is wall voltage.
Frequently asked questions
How many watts is 5V 2A?
10W: 5 volts × 2 amps = 10 watts. Every profile reads the same way: voltage times current.
Why not add 15 + 18 + 18?
Because they are alternative modes for one port, not simultaneous outputs. The charger delivers a single mode at a time, so its power is the maximum: 18W, not 51W.
Does the phone always take the maximum?
No. Charger, cable and device negotiate a shared mode. An old phone on a new 65W brick takes what it knows — for example 5V × 2A = 10W.
What does 3.3-11V⎓3A mean?
A programmable range (PPS): voltage adjusts between 3.3 and 11 V at 3 A. Maximum power sits at the top: 11 × 3 = 33W.
Is 28V⎓5A really 140W?
Yes: 28 × 5 = 140W, a fixed USB PD 3.1 Extended Power Range (EPR) profile. You need EPR-capable cable and device too.
Sources and method
- USB PD fixed voltages — 5, 9, 15, 20 V standard and 28, 36, 48 V (140, 180, 240W) extended — follow the USB-IF USB Charger page.
- Every watt figure on the page is a direct V × A multiplication, automatically checked against the shipped parser; ranges peak at the top voltage.
- The ⎓ symbol means direct current (DC); the decoder treats it like a slash, an equals sign or a space.