Raspberry Pi Pico Pinout
Pico 40 pins: GPIO / ADC / power + default UART·I2C·SPI.
What it does: Look up the position and function of each Pico pin, which ones can do ADC, and where the default UART/SPI/I2C are.
When to use it: When wiring the Pico, choosing function pins, or avoiding the internal pins that are not on the header.
Disclaimer: This result is a reference estimate. For actual production, refer to the device datasheet / local regulations as authoritative.
With the USB at the top: left column 1→20, right column 40→21. Remappable functions? .
MEANS GP25 (onboard LED) and GP23/24 are internal and not on the header; all GPIO are 3.3V, not 5V tolerant.
No history yet. Each calculation is automatically saved to this device.
How to use the Pico pinout reference
Orient the header → pick function pins → remember it is remappable.
- 01
Orient the header
With the USB at the top, the left column reads GP0…GP15 top to bottom, and the right column reads VBUS…GP16 top to bottom.
- 02
Pick the function pins
ADC uses GP26/27/28; the defaults are UART0=GP0/1, SPI0=GP16-19, and I2C0 commonly on GP4/5.
- 03
Remember it is remappable
On the RP2040, UART/SPI/I2C can mostly be moved to other GP pins — the table lists the common defaults; the firmware configuration is authoritative.
Common function pins (default / typical)
RP2040 functions can be MUXed to multiple pins; the table below shows the most common assignments.
| Function | Pin |
|---|---|
| ADC analog input | GP26 (ADC0) · GP27 (ADC1) · GP28 (ADC2) |
| UART0 | GP0 = TX · GP1 = RX |
| I2C0 (common) | GP4 = SDA · GP5 = SCL |
| SPI0 | GP16 MISO · GP17 CS · GP18 SCK · GP19 MOSI |
| Power | VBUS(40)=USB 5V · VSYS(39)=1.8–5.5V in · 3V3(36)=output |
Raspberry Pi Pico Datasheet / official pinout diagram.
Common questions, answered in 3 minutes
Is the Pico GPIO 5V tolerant?
No. The RP2040 GPIO is 3.3V logic and feeding 5V will damage it. To interface a 5V signal, use level shifting.
Which pin is the onboard LED?
GP25 — but it connects to the LED internally and is not routed to the 40-pin header. The same goes for GP23/GP24 (power management / VBUS sense); none of them are on the header.
Why are the UART/I2C pins different from someone else's?
The RP2040 uses function MUXing, so many peripherals can map to multiple GP pins. This table gives the common defaults; you can freely move them to other pins in firmware.
What is the difference between VSYS and VBUS?
VBUS is the 5V coming in from USB; VSYS is the main system power input (1.8–5.5V, converted to 3.3V by the onboard buck-boost). For battery power, connect to VSYS.
How do I use the analog inputs?
Only GP26/27/28 (ADC0-2) can read analog values, plus an internal temperature channel ADC4; ADC_VREF/AGND are their reference and ground.
Standards and sources referenced by this tool
| Item | Value / Formula | Source |
|---|---|---|
| Pin layout | Pico Datasheet | Raspberry Pi official |
| GPIO level | 3.3V (not 5V tolerant) | RP2040 |
The official Pico pinout diagram is authoritative; functions can be MUXed and the default assignments are for reference only.