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ESP32 Battery Life Calculator (Deep Sleep)
Enter your battery capacity, wake interval, active current and deep-sleep current — get an instant estimate of how long your ESP32 will actually run. Runs entirely in your browser.
18650 ≈ 3000, CR2450 ≈ 550
Wi-Fi TX ≈ 80–150
sensor read + connect + send
bare module ≈ 10, board w/ LDO ≈ 100+
3600 = once per hour
LDO ≈ 65, buck ≈ 90
Why real battery life is worse than your estimate
- Peripheral leakage: LDO quiescent current, pull-up resistors and sensor standby current often dwarf the ESP32's own 10 µA.
- Wi-Fi connect time: DHCP plus an MQTT handshake takes 1–3 seconds at 80–150 mA. That, not sleep current, is what drains the cell.
- Self-discharge and temperature: leave 30% headroom for cold weather and ageing cells.
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<iframe src="https://espio.dev/embed/sleep/" width="100%" height="640" frameborder="0" loading="lazy" title="sleep calculator" style="border:1px solid #e3e6ea;border-radius:10px"></iframe>