Battery Life Calculator

• •Use the Battery Life Calculator when you need accurate results quickly without the risk of manual computation errors or unit conversion mistakes.
• •Use it to verify calculations made by hand or in spreadsheets — an independent check can catch errors before they lead to costly decisions.
• •Use it to explore how changing input parameters affects the output — a quick way to develop intuition and identify the most influential variables.
• •Use it when collaborating with others to ensure everyone is working from the same numbers and applying the same assumptions.

The Battery Life Calculator is a free, browser-based calculation tool for engineers, students, and technical professionals. Estimate battery life based on battery capacity and device power consumption. It implements standard formulas and supports both metric (SI) and imperial unit systems with automatic unit conversion. All calculations are performed instantly in your browser with no data sent to a server. Use this calculator as a quick reference and sanity-check tool during design, analysis, and learning. Always verify results against primary engineering references and applicable standards for any safety-critical application.

The Battery Life Calculator estimates how long a battery will last based on its capacity and the device's power consumption. This is useful for electronics projects, IoT devices, portable equipment, and understanding smartphone battery claims. Enter the battery capacity in milliamp-hours (mAh) and the average current draw in milliamps (mA) to calculate the expected runtime.

• !Not accounting for the Peukert effect, where high discharge rates reduce effective capacity.
• !Ignoring self-discharge; batteries lose charge over time even when not in use.
• !Using peak power consumption instead of average, leading to overly pessimistic estimates.
• !Forgetting to convert between mAh and Ah (1 Ah = 1000 mAh).