ESP32 Overview

History

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Before the ESP32: the problem it solved

In the early 2010s, putting a hobby project or a low-volume product on a Wi-Fi network was disproportionately expensive. The microcontroller might cost two dollars; the Wi-Fi module bolted onto it cost twenty or thirty, needed its own certification, and usually spoke a proprietary AT-command protocol over a serial link. Wi-Fi was something you added to a design, not something that came with it.

Specifications

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Full comparison

Variant	ISA	Cores	Clock	SRAM	Radios	GPIO	USB	Sleep	Status	From
ESP32	Xtensa	2 + LP	240 MHz	520 KB	Wi-Fi 4 + BT Classic/LE	34	—	~10 µA	Production	$1.50
ESP32-S2	Xtensa	1 + LP	240 MHz	320 KB + 16 KB RTC	Wi-Fi 4 only	43	OTG Full Speed	~5–7 µA	Production	$1.25
ESP32-S3	Xtensa	2 + LP	240 MHz	512 KB + 16 KB RTC	Wi-Fi 4 + BLE 5	45	OTG Full Speed	~7 µA	Production	$1.85
ESP32-S31	RISC-V	2 + LP	320 MHz	512 KB	Wi-Fi 6 + BT 5.4 + 802.15.4 + 1 GbE	60	OTG	Not yet published	Production	$3.80
ESP32-C2	RISC-V	1	120 MHz	272 KB	Wi-Fi 4 + BLE 5	14	Serial/JTAG	<8 µA	Production	$1.00
ESP32-C3	RISC-V	1	160 MHz	400 KB	Wi-Fi 4 + BLE 5	22	Serial/JTAG	~5 µA	Production	$1.00
ESP32-C5	RISC-V	1 + LP	240 MHz	384 KB + 16 KB LP	Dual-band Wi-Fi 6 + BLE 5 + 802.15.4	29	Serial/JTAG	~12 µA	Production	$2.50
ESP32-C6	RISC-V	1 + LP	160 MHz	512 KB + 16 KB LP	Wi-Fi 6 + BLE 5.3 + 802.15.4	30	Serial/JTAG	7 µA	Production	$1.85
ESP32-C61	RISC-V	1 + LP	160 MHz	320 KB + 4 KB LP	Wi-Fi 6 + BLE 5	30	Serial/JTAG	~10 µA	Production	$1.46
ESP32-H2	RISC-V	1 + LP	96 MHz	320 KB + 4 KB LP	BLE 5 + 802.15.4 (no Wi-Fi)	19	Serial/JTAG	7 µA	Production	$1.39
ESP32-H21	RISC-V	1 + LP	96 MHz	320 KB + 128 KB ROM	BLE 5 + 802.15.4 (no Wi-Fi)	19	Serial/JTAG	5 µA	Sampling	—
ESP32-H4	RISC-V	2 + LP	96 MHz	384 KB (expandable PSRAM)	BLE 5.4 + 802.15.4 (no Wi-Fi)	35	OTG	~7 µA	Sampling	—
ESP32-P4	RISC-V	2 + LP	400 MHz	768 KB L2MEM + 32 KB LP	None (wired / companion radio)	55	OTG High Speed	~25 µA	Production	$4.00
ESP32-E22	RISC-V	2 + LP	500 MHz	1 MB	Tri-band Wi-Fi 6E + BT Classic/LE 5.4	30	Host	Host-managed	Co-processor	—

Cores counts high-performance cores; “+ LP” means a separate low-power core or ULP coprocessor is also present. USB distinguishes real OTG (which can implement USB device classes) from a Serial/JTAG peripheral (which cannot) — see Specifications. From is Espressif's published reference sample price for the cheapest orderable part number in the series and excludes flash and PSRAM options. Sleep currents are typical values, some estimated rather than characterised.

Pricing

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Boards & Modules

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Chip, module, or development board?

Espressif sells the same silicon in three forms, and picking the wrong one wastes either money or months.

The chip

A bare integrated circuit. It contains the CPU, RAM, peripherals and radio — and nothing else. It cannot be powered on and used directly: you must supply the crystal oscillator circuit, the flash memory circuit, the RF matching network and the antenna yourself.

Use Cases

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How to read this page

Each section below covers an application area, lists the concrete products people build in it, and names the part that fits. Where two chips are plausible, both are given with the deciding factor.

A recurring pattern worth internalising: the right answer is often two chips. The P4 has no radio; the H2 has no Wi-Fi; the E22 has no application processor. Espressif designed these gaps deliberately, expecting pairing — and supports it through ESP-Hosted, which lets one chip run the radio stack on behalf of another over SDIO, SPI or UART.

Choosing

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The short version

If you do not want to read the rest of this page:

If you are…	Buy
Starting a new connected product	ESP32-C6
Building something with a screen or camera	ESP32-S3
Trying to hit the lowest possible cost	ESP32-C3 (or C2 at volume)
Building a battery sensor for a mesh	ESP32-H2
Driving a 1080p display or encoding video	ESP32-P4 + ESP32-C6
Needing 5 GHz Wi-Fi	ESP32-C5
Needing Bluetooth Classic	ESP32 (original) or ESP32-S31
Needing every radio plus gigabit Ethernet	ESP32-S31
Adding Wi-Fi 6E to a Linux host	ESP32-E22

Everything below is the reasoning, in the order that actually eliminates options fastest.

Ecosystem

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The frameworks

An unusual property of this platform: almost everything ends up on ESP-IDF. The Arduino core is a layer over it, MicroPython runs as a FreeRTOS task inside it, and ESPHome now builds against it by default. The frameworks differ mainly in how far above it they sit.

ESP-IDF — the foundation

Espressif’s official IoT Development Framework: C and C++, FreeRTOS, CMake, and a Kconfig-based configuration system familiar to anyone who has built a Linux kernel.

Sources & Method

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Method

Everything on this site was compiled and cross-checked in September 2026. The approach was:

Prefer primary sources. Specifications come from Espressif’s own product pages, the SoC and module product selectors, the ESP-Techpedia board-selection comparison, and the series datasheets on documentation.espressif.com.
Prices are Espressif’s own published figures. Every price on the pricing page is Espressif’s “sample price for reference” as displayed on its product selector, scraped and transcribed rather than estimated. Third-party board prices are street prices and clearly marked as approximate.
Flag status honestly. Each variant carries a production status. Announced is not available; sampling is not volume production. The ESP32-C5 — announced 2022, in mass production 2025 — is why this matters.
Separate measurement from marketing. Where a vendor claim is a specification rather than a characterised number, or an estimate extrapolated from similar silicon, it is labelled as such.
Record disagreements rather than silently picking one. See the discrepancies section below.

Primary sources

Espressif product and specification pages

Espressif SoC product selector — the authoritative list of current SoCs, part numbers, memory configurations, package sizes and reference sample prices
Module product selector — WROOM, WROVER, MINI, SOLO and PICO part numbers and prices
Development kit listing — official kit prices
Individual SoC product pages, used for the newest parts where datasheets are not yet indexed: ESP32-S31 , ESP32-P4 , ESP32-C5 , ESP32-C61 , ESP32-H4 , ESP32-H21 , ESP32-E22

Espressif technical documentation

ESP-Techpedia: board selection — the cross-family comparison table used for CPU, memory, radio, peripheral and longevity-commitment data, plus the official development-board catalogue by application area
documentation.espressif.com — series datasheets and technical reference manuals. This is Espressif’s current canonical documentation host; older espressif.com/sites/default/files/documentation/... paths often still resolve but are being phased out
ESP-IDF Programming Guide — peripheral capabilities per target, and the soc_caps.h definitions that are the ground truth for feature-presence questions
Espressif Developer Portal — release announcements, including the ESP-IDF v6.0 release and the ESP32-C5 mass-production announcement
Espressif part numbers explained — the basis for the suffix decoder on the boards page

Corporate history

Espressif milestones — founding date, office openings, certifications and product announcements
Espressif: over 1 billion shipments (October 2023) and the 100-million milestone
Product announcements including ESP32-C5 , ESP32-C5 mass production , ESP32-P4 , ESP32-H4 , ESP32-E22 and ESP32-S31 mass production
Public encyclopaedic records on Espressif Systems were used to corroborate the founding, ESP8266 launch, ESP32 launch and STAR Market listing dates. Content from those sources has been paraphrased rather than reproduced.

Software ecosystem

espressif/esp-idf and the ESP-IDF release notes
ESPHome 2026.7.0 release notes — the native toolchain default and the EN 18031 security work
MicroPython esp32 port
esp-rs — esp-idf-sys, esp-idf-hal, esp-idf-svc
espressif/esp-adf
ESP Component Registry

Community and secondary sources

Used for cross-checking, for peripheral-level detail that datasheet summaries omit, and for third-party board information. Content from these sources has been paraphrased and independently reorganised.

ESP32

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Why it still matters

Ten years after launch, the original ESP32 is beaten on almost every individual specification by something newer in the family. It has no Wi-Fi 6, no BLE 5, no 802.15.4, the highest active current, and an instruction set Espressif has stopped designing new parts around.

It nonetheless remains a defensible choice, for three reasons that no newer part fully replaces.

It is the only ESP32 with Bluetooth Classic — specifically BR/EDR alongside LE 4.2. If your product needs to pair with a phone as an A2DP audio sink, act as a hands-free device, or talk to legacy Bluetooth serial equipment, the original ESP32 and the very new S31 are your only options in the family. Every part in between is Bluetooth LE only.

ESP32-C2

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What it is for

The C2 exists to win price-driven design contests. If you are building a smart plug, a lamp controller or a Wi-Fi relay in six-figure volumes, the difference between a $1.00 chip and a $1.85 one is real money, and the C2’s job is to be the cheapest part that still speaks Wi-Fi and BLE 5.

Everything about it follows from that goal. The package is 4×4 mm, the smallest in the family. The core is a single RISC-V at 120 MHz — slower than the C3’s 160 MHz. SRAM is 272 KB. There are 14 GPIOs. And an unusually long list of peripherals simply is not present.

ESP32-C3

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Why it is still recommended

The C3 was announced in 2020 as Espressif’s first RISC-V chip and its answer to the question “what replaces the ESP8266?”. Six years later it is neither the fastest, the most efficient nor the most featured part in the family — and it is still the one to recommend to most people building most things.

The argument is boring and correct: at $1.00 for the chip and $8 for the development board, with 400 KB of SRAM, a 160 MHz core, Wi-Fi, Bluetooth LE 5 and hardware ECC, the C3 has no gap between what it claims and what it delivers. Every framework supports it properly. Every tutorial works. The errata are known and worked around. Nothing about it will surprise you at integration time.

ESP32-C5

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The one thing only it can do

“Why won’t my ESP32 connect to my Wi-Fi?” has, for a decade, had one overwhelmingly common answer: because the network is 5 GHz and every ESP32 radio was 2.4 GHz only. The C5 is the part that fixes this. It is the first — and as of now the only — Espressif SoC with a dual-band Wi-Fi 6 radio covering both 2.4 GHz and 5 GHz, with backward compatibility down to 802.11a/b/g/n/ac.

ESP32-C6

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Why this is the default recommendation

The C6 is the chip that most new ESP32 designs should start with, and the reasoning is that it is the only part where nothing important is missing for a typical connected device.

It has the modern radio set: Wi-Fi 6, Bluetooth 5.3 with Mesh, and 802.15.4 for Thread and Zigbee — so it can be a Matter device over Wi-Fi or over Thread, a Zigbee node, or a bridge between them. It has a dedicated low-power core so sleep patterns can be sophisticated. It sleeps at 7 µA. It has 512 KB of SRAM, the joint-largest in the C-series. It has 30 GPIOs. And it has the strongest security certification of any chip in the family.

ESP32-C61

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The proposition

The C61 is best understood as a cost-reduced C6. Same 160 MHz single RISC-V core, same Wi-Fi 6 on 2.4 GHz, same Bluetooth LE 5, same 30 GPIOs — for $1.46 instead of $1.85, with modules at $2.14 instead of $2.50.

What pays for the difference:

	ESP32-C6	ESP32-C61
802.15.4 (Thread, Zigbee)	Yes	No
Low-power core	20 MHz RISC-V	LP peripherals only
SRAM	512 KB	320 KB
Bluetooth	5.3 + Mesh	5
ADC channels	7	1
RMT	4 channels	None
In-package PSRAM	No (external only)	Up to 8 MB
Deep sleep	7 µA	~10 µA
Security certification	PSA Level 2	APM + PMP, no PSA L2
From	$1.85	$1.46

The trades are coherent for a specific kind of product: a mains-powered Wi-Fi device — an appliance controller, a Wi-Fi adapter, a POS terminal, a smart-home actuator — that benefits from Wi-Fi 6’s congestion behaviour but will never join a Thread network and does not need a coprocessor running during sleep.

ESP32-E22

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A different kind of product

Every other chip on this site is a microcontroller you write firmware for. The E22 is not. It is a Radio Co-Processor (RCP): a self-contained networking subsystem that attaches to a host processor — typically running Linux — and presents itself as a network interface. The host runs the application; the E22 runs the entire Wi-Fi and Bluetooth stack.

This is a new product line for Espressif, announced in January 2026 and Wi-Fi 6E certified in June 2026. Strategically it moves the company from “cheap microcontrollers with radios” into competition with the connectivity silicon that goes into routers, set-top boxes and laptops.

ESP32-H2

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Why remove Wi-Fi

Wi-Fi is expensive in every sense: die area, peak current, average current, and the RAM the stack consumes. A Wi-Fi transmission can draw a few hundred milliamps in bursts, and even an idle associated station must wake periodically to listen for beacons.

For a door sensor, a temperature probe or a light switch, none of that is wanted. What is wanted is a radio that can send twenty bytes, occasionally, using as little energy as possible, on a network that routes around dead nodes. That radio is IEEE 802.15.4 — the physical layer beneath both Thread and Zigbee — and the H2 is Espressif’s part built entirely around it.

ESP32-H21

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What changed from the H2

The H21 is not a new architecture. It is the same basic proposition as the H2 — a 96 MHz single-core RISC-V part with Bluetooth LE and 802.15.4 and no Wi-Fi — with three targeted improvements aimed squarely at battery-powered mesh nodes.

An on-chip DC-DC converter. This is the most consequential change and the least visible on a specification sheet. Without it, the radio’s supply is derived through a linear regulator, and the difference between the battery voltage and the radio’s operating voltage is burned as heat. A switching converter recovers most of that. Espressif quotes roughly 8.2 mA during receive as a result.

ESP32-H4

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Why it is more than an H2 refresh

The H2 and H21 are sensor-node chips: one slow core, 19 pins, minimal peripherals. The H4 keeps the H-series radio philosophy — 802.15.4 plus Bluetooth LE, no Wi-Fi — but scales everything else up enough to build a device rather than a sensor.

Two RISC-V cores instead of one, at 96 MHz, with a dedicated low-power domain for selected peripherals. Two cores in a mesh device is more useful than it sounds: the 802.15.4 stack and the Bluetooth stack are both timing-sensitive, and separating protocol work from application work removes a class of jitter problem.

ESP32-P4

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The chip that gave up the radio

Every other part in this family is defined by its radio. The P4 is defined by not having one. There is no Wi-Fi, no Bluetooth, no 802.15.4 — and the die area, power budget and pin count that would have gone to a radio went into application performance and I/O instead.

The result is by some distance the most capable Espressif application processor:

ESP32-S2

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Why it exists

The S2 was the first structural departure from the original ESP32, and its design brief was subtractive: remove Bluetooth entirely to cut die area, cost and power, then reinvest the savings in a native USB controller, more pins and more touch channels.

At the time that was a coherent proposition. A great many Wi-Fi products — smart plugs, panels, appliance controllers — never use Bluetooth for anything except initial provisioning, and provisioning can be done over a SoftAP instead. Paying for a Bluetooth radio you disable in firmware is waste.