Raspberry Pi GPIO — LED Reference

40-pin header (Pi 1 B+ / 2 / 3 / 4 / 5 / Zero). All GPIO pins are 3.3 V logic. Per-pin source/sink limit ≈ 16 mA, total across the header ≈ 50 mA. Target 5–10 mA per LED to stay well inside those budgets.

Pinout map

              3V3  (1) (2)  5V
   GPIO2  SDA  (3) (4)  5V
   GPIO3  SCL  (5) (6)  GND
   GPIO4       (7) (8)  GPIO14  TXD
          GND  (9)(10)  GPIO15  RXD
   GPIO17     (11)(12)  GPIO18  PWM0
   GPIO27     (13)(14)  GND
   GPIO22     (15)(16)  GPIO23
          3V3 (17)(18)  GPIO24
   GPIO10 MOSI(19)(20)  GND
   GPIO9  MISO(21)(22)  GPIO25
   GPIO11 SCLK(23)(24)  GPIO8   CE0
          GND (25)(26)  GPIO7   CE1
   ID_SD      (27)(28)  ID_SC          <- reserved (HAT EEPROM)
   GPIO5      (29)(30)  GND
   GPIO6      (31)(32)  GPIO12  PWM0
   GPIO13 PWM1(33)(34)  GND
   GPIO19 PWM1(35)(36)  GPIO16
   GPIO26     (37)(38)  GPIO20
          GND (39)(40)  GPIO21

Pins safe for LEDs

Free to use without conflicting with default peripherals:

GPIO	Header pin	Notes	Led Use
4	7		Power LED
5	29		Ethernet Activity LED
6	31		Led 01 - Disk Space
12	32	hardware PWM0	Led XX -
13	33	hardware PWM1	Led XX -
16	36		Led 02 - Disk Space
17	11		Led 03 - Disk Space
18	12	hardware PWM0	Led XX -
19	35	hardware PWM1	Led XX -
20	38		Led 04 - Disk Space
21	40		Led 05 - Disk Space
22	15		Led 06 - Disk Space
23	16		Led 07 - Disk Space
24	18		Led 08 - Disk Space
25	22		Led 09 - Disk Space
26	37		Led 10 - Disk Space
27	13

GPIO 12 / 13 / 18 / 19 are the hardware PWM channels — use these if you want smooth brightness/fade.

Pins to avoid (or use with care)

GPIO	Pin(s)	Why
0, 1	27, 28	Reserved for HAT ID EEPROM — do not use
2, 3	3, 5	I²C, has 1.8 kΩ pull-ups to 3V3 — pulled high
7, 8	26, 24	SPI0 CE1/CE0
9, 10, 11	21, 19, 23	SPI0 MISO / MOSI / SCLK
14, 15	8, 10	UART TXD/RXD — serial console by default

If the corresponding interface is disabled in raspi-config these pins become regular GPIO and are fine for LEDs.

Wiring

  GPIOxx ──┬── [ R ] ──▶|── GND
           │           LED

Resistor on either side of the LED is fine. Anode (long leg, flat side of bulb is cathode) toward GPIO, cathode toward GND.

Resistor values (3.3 V supply)

R = (3.3 − Vf) / I. Picking the next-larger standard E12 value.

LED colour	Vf (typ.)	10 mA → calc	Use	5 mA → calc	Use
Red	2.0 V	130 Ω	150 Ω	260 Ω	330 Ω
Yellow	2.1 V	120 Ω	150 Ω	240 Ω	270 Ω
Orange	2.0 V	130 Ω	150 Ω	260 Ω	330 Ω
Green (std)	2.1 V	120 Ω	150 Ω	240 Ω	270 Ω
Green (hi-b)	3.0 V	30 Ω	47 Ω	60 Ω	100 Ω
Blue	3.0 V	30 Ω	47 Ω	60 Ω	100 Ω
White	3.0 V	30 Ω	47 Ω	60 Ω	100 Ω

A 220 Ω resistor is a safe universal default for any colour from a 3.3 V GPIO — gives roughly 6 mA on a red, ~1.5 mA on a blue (dim but visible). Use 330 Ω if you only need an indicator.

Quick test (Python, gpiozero)

from gpiozero import LED
from time import sleep

led = LED(17)          # BCM numbering — header pin 11
while True:
    led.on();  sleep(0.5)
    led.off(); sleep(0.5)

For PWM brightness use PWMLED(12) etc. on one of the hardware-PWM-capable pins.