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ESP32 Pinouts

// FAST REFERENCE • PINOUTS • DATASHEETS • TRM • SCHEMATICS

A fast personal reference. Not a datasheet, and not a guarantee of correctness. Pinouts on the internet are often simplified, out of date or specific to one board variant. The datasheet, the technical reference manual and your board's schematic are the source of truth. ESP32 GPIO is 3.3 V and not 5 V tolerant, and several pins do things at boot that a pinout picture does not show. Open for the full scope limits.

What this page is

  • Pinouts on the internet are often simplified, out-of-date, or board-variant-specific. Use the datasheet and TRM, and the board schematic where one is available, as the source of truth.
  • Some boards, especially CYD-style display boards, vary by manufacturer and revision. Always verify your exact PCB rather than a board with the same name.
  • This tool is a personal fast reference. It is not a guarantee of correctness.

"ESP32" is a family, not a part. The S2, S3, C3, C6 and H2 have different cores, different peripherals and different pin maps, and a diagram for one is wrong for another.

The pins that bite

  • 3.3 V logic, not 5 V tolerant. There is no series protection on a bare GPIO. A 5 V sensor output wired straight to a pin can damage the chip, sometimes immediately and sometimes weeks later.
  • Strapping pins. On the classic ESP32, GPIO0, 2, 4, 5, 12 and 15 are sampled at reset and set boot mode, flash voltage and logging. A pull-up or pull-down you added for your circuit can stop the board booting, and GPIO12 pulled high can run the flash at the wrong voltage.
  • GPIO6 to GPIO11 connect to the integrated SPI flash on most modules. Using them is not a wiring mistake you recover from at runtime.
  • GPIO34 to GPIO39 are input only. No output driver, no internal pull-up or pull-down. A pinout that lists them as GPIO does not tell you that.
  • ADC2 is unavailable while Wi-Fi is active, which turns a working analog read into an intermittent one the moment the radio comes up.
  • Current limits are absolute maximums, not design targets, per pin and in total across the chip. Drive a relay or an LED string from a GPIO and you are outside the datasheet.

Never use this page as the basis for

  • Production hardware, a PCB layout, or a bill of materials, without checking every pin against the current datasheet and the module's own documentation.
  • Anything connected to mains, to a battery pack that can deliver fault current, or to a motor or heater.
  • Safety, medical, automotive or life-critical functions of any kind.
  • Certification, compliance or regulatory submissions, including radio approvals, which depend on the module and its antenna rather than a pin map.

Before you wire anything

Open the datasheet and technical reference manual for your exact chip variant, and the schematic for your exact board revision. Confirm the pin function, the boot behaviour, the voltage and the current limit there. Where a board vendor publishes no schematic, treat every pin as unverified and measure before you connect.

No warranty. No liability. You assume all risk. This page and its data are provided as-is and as-available, without warranty of any kind, express or implied, including accuracy, completeness, timeliness, reliability, fitness for a particular purpose, merchantability, engineering or professional suitability, regulatory or certification acceptability, or non-infringement. To the maximum extent permitted by law, the author accepts no liability for any loss, injury, death, damage, cost or claim arising from use of or reliance on this page.

Independent verification required. Verify every pin against the manufacturer's current datasheet, technical reference manual and board schematic before wiring, programming or purchasing. Those documents control; where this page disagrees with them, this page is wrong.

Consequential damages excluded. To the maximum extent permitted by law, in no event will the author or maintainers be liable for any direct, indirect, incidental, special, exemplary, punitive or consequential damages, including damaged hardware, lost work, or loss of use, data, profits or business interruption, however caused and on any theory of liability, whether in contract, strict liability or tort including negligence, arising out of or in connection with this page, even if advised of the possibility of such damage.

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Severability. If any part of this notice is held unenforceable, the remainder continues to apply, and the unenforceable part is limited to the least extent necessary rather than struck out.

Boards

Click View to open the pinout viewer and official documentation links.

3.3 V logic, not 5 V tolerant, and several pins are sampled at boot. These diagrams are simplified and can be out of date or specific to another board revision. Confirm every pin against the datasheet, the technical reference manual for your exact variant, and your board schematic before you wire anything.

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