Raspberry Pi · Single-board computer

Raspberry Pi 40-pin GPIO Header

The J8 header shared by every 40-pin Raspberry Pi, from the Model B+ through the Pi 5. Names are BCM numbers, which is what libgpiod, pigpio and the Python GPIO libraries expect.

Cheat sheet (SVG)

Logic level: 3.3 V
Package: 2x20 2.54 mm header (J8)

1.Pinout diagram

Highlight a signalhover to preview, click to keep

Odd pins

RPI 40-PIN

Even pins

Pin detail

Hover a pin for its mappings and gotchas. Click to keep it here.

Logic level: 3.3 V
Package: 2x20 2.54 mm header (J8)

Fig. 1. Raspberry Pi 40-pin GPIO Header, 2x20 2.54 mm header (J8). Hover or tap a signal to light up every pin that carries it.

2.Caution

Pins are 3.3 V only. Driving one from a 5 V output will damage the SoC, level shift anything 5 V.
GPIO2 and GPIO3 carry fixed 1.8 kΩ pull-ups to 3V3 on the board, so they cannot be used as plain inputs with an external pull-down.
Total current drawn from all 3V3 pins combined should stay under roughly 50 mA; per-pin GPIO drive is safe to about 16 mA, 50 mA across the whole header.
GPIO0/GPIO1 (pins 27/28) are reserved for HAT ID EEPROM detection. Avoid them unless you are building a HAT.
Pin numbering is physical here. BCM (Broadcom) numbers are the pin names; the obsolete WiringPi scheme is a third numbering you will still see in old forum posts.

3.Full pin reference

Every pin, alias and mapping. This is the table that prints.

Table 1. Pin assignments.

Complete pin reference for Raspberry Pi 40-pin GPIO Header
Pin	Name	Also called	Functions	Notes
1	3V33.3 V	-	3.3 V supply out	~50 mA budget shared with pin 17.
2	5V5 V	-	5 V supply out	Fed straight from the USB-C / micro-USB input, upstream of the 3V3 regulator.
3	GPIO2I²C	BCM 2, SDA1, I2C1 SDA	I2C1 SDA	Fixed 1.8 kΩ pull-up to 3V3.
4	5V5 V	-	5 V supply out
5	GPIO3I²C	BCM 3, SCL1, I2C1 SCL	I2C1 SCL	Fixed 1.8 kΩ pull-up to 3V3. Also wakes the Pi from halt when pulled low.
6	GND	-	Ground
7	GPIO4Clock	BCM 4, GPCLK0	GPCLK0	Default 1-Wire bus pin (w1-gpio overlay), used by DS18B20 sensors.
8	GPIO14UART	BCM 14, TXD0, TXD	UART0 TXD
9	GND	-	Ground
10	GPIO15UART	BCM 15, RXD0, RXD	UART0 RXD
11	GPIO17	BCM 17	SPI1 CE1
12	GPIO18PWMClock	BCM 18, PCM_CLK	PWM0, PCM/I2S CLK, SPI1 CE0	The pin WS2812/NeoPixel libraries use, because it reaches PWM0 via DMA.
13	GPIO27	BCM 27	SD1 DAT3
14	GND	-	Ground
15	GPIO22	BCM 22	SD1 CLK
16	GPIO23	BCM 23	SD1 CMD
17	3V33.3 V	-	3.3 V supply out
18	GPIO24	BCM 24	SD1 DAT0
19	GPIO10SPI	BCM 10, MOSI	SPI0 MOSI
20	GND	-	Ground
21	GPIO9SPI	BCM 9, MISO	SPI0 MISO
22	GPIO25	BCM 25	SD1 DAT1
23	GPIO11SPIClock	BCM 11, SCLK	SPI0 SCLK
24	GPIO8SPI	BCM 8, CE0	SPI0 CE0
25	GND	-	Ground
26	GPIO7SPI	BCM 7, CE1	SPI0 CE1
27	GPIO0I²C	BCM 0, ID_SD	ID EEPROM SDA	Reserved for HAT identification at boot.
28	GPIO1I²C	BCM 1, ID_SC	ID EEPROM SCL	Reserved for HAT identification at boot.
29	GPIO5	BCM 5	GPCLK1	Pulling low wakes a halted Pi 4 / Pi 5.
30	GND	-	Ground
31	GPIO6	BCM 6	GPCLK2
32	GPIO12PWM	BCM 12	PWM0
33	GPIO13PWM	BCM 13	PWM1
34	GND	-	Ground
35	GPIO19SPIPWM	BCM 19, PCM_FS	SPI1 MISO, PCM/I2S FS, PWM1
36	GPIO16SPI	BCM 16	SPI1 CE2
37	GPIO26	BCM 26	SD1 DAT2
38	GPIO20SPI	BCM 20, PCM_DIN	SPI1 MOSI, PCM/I2S DIN
39	GND	-	Ground
40	GPIO21SPIClock	BCM 21, PCM_DOUT	SPI1 SCLK, PCM/I2S DOUT

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Primary sources

Found a wrong pin? The whole board is one file, data/boards/raspberry-pi-40-pin.json.

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