Battery Capacity Calculator

• •Use the Battery Capacity 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 Capacity Calculator is a free, browser-based calculation tool for engineers, students, and technical professionals. Calculate the required battery capacity for a desired runtime and 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 Capacity Calculator determines the minimum battery capacity needed to power a device for a specified duration. When designing portable electronics, IoT devices, or backup power systems, selecting the right battery capacity is critical. This calculator factors in your device's power consumption, desired runtime, and a safety margin for real-world efficiency losses.

• !Not including a safety margin, leading to shorter-than-expected runtime.
• !Using peak current draw instead of average, oversizing the battery unnecessarily.
• !Forgetting that voltage affects energy capacity; mAh comparisons are only valid at the same voltage.