How does the Battery Life Calculator work?

The calculator estimates battery life by dividing the battery capacity (in mAh) by the device's current draw (in mA). This provides the estimated runtime in hours. For example, a 2000 mAh battery powering a device that draws 200 mA would last approximately 10 hours.

When should I use this calculator?

Use this calculator when you want a quick estimate of how long a battery will power a specific device. It is especially helpful for electronics projects, portable devices, and battery-powered systems. Simply enter the battery capacity and the device’s current draw to get an instant result.

What do mAh and mA mean?

mAh (milliamp-hours) measures the total energy capacity of a battery, while mA (milliamps) measures the rate at which a device consumes current. Dividing capacity by current draw tells you how many hours the battery can theoretically supply power.

Why is my real-world battery life different from the result?

The calculator provides an ideal estimate based on a simple mathematical formula. In real-world conditions, factors such as battery age, temperature, voltage drops, and efficiency losses can reduce actual runtime. Consider the result as an approximation rather than an exact value.

Can I use this calculator for any type of battery?

Yes, as long as the battery capacity is provided in mAh and the device current draw is in mA. The formula works for lithium-ion, alkaline, NiMH, and other battery types. Just ensure both values use the correct units for accurate results.

What happens if the device current draw changes over time?

If the current draw varies, the result will only reflect the estimate based on the value you enter. For devices with fluctuating power usage, you can calculate an average current draw for a more accurate estimate. This will give a closer approximation of actual battery life.

What does the DC Voltage Drop Calculator compute?

This calculator determines the total voltage drop across a cable in a simple DC circuit. It uses the current, one-way cable length, and cable resistance per meter to calculate how much voltage is lost in the wiring. The result is provided in volts (V).

Why does the formula multiply by 2?

The formula includes a factor of 2 to account for the round-trip path of the current. In a DC circuit, current travels from the source to the load and back again through a return conductor. This means the total effective cable length is double the one-way length.

When should I use this calculator?

You should use this calculator when designing or evaluating a DC electrical system, such as solar setups, automotive wiring, or battery-powered circuits. It helps ensure that voltage drop stays within acceptable limits for proper equipment operation. Excessive voltage drop can reduce performance or cause malfunction.

How do I find the cable resistance per meter (Ω/m)?

Cable resistance per meter is typically provided by the cable manufacturer in technical datasheets. It depends on the conductor material (such as copper or aluminum) and the wire gauge or cross-sectional area. Make sure the value is in ohms per meter (Ω/m) before entering it into the calculator.

Electrical & Electronics

Ohm's law, power, resistor, capacitor, LED, and electrical engineering calculators.

Explore Other Categories

Financial Calculators (94) Health & Fitness (91) Science & Engineering (53) Business & Retail (45) Construction & Home (40) Math Calculators (31) Travel & Geography (15) Statistics & Probability (14)

Electrical & Electronics

Battery Life Calculator

DC Voltage Drop Calculator

Electrical Energy Consumption Calculator

Electricity Cost Calculator

Joule Heating Power Calculator (I²R)

LED Series Resistor Calculator

Lumens to Lux Calculator

Parallel Resistor Calculator

Power Factor Calculator

Power to Current Calculator

RC Time Constant Calculator

Three-Phase Power Calculator

Voltage Divider Calculator

Voltage Gain Calculator

Explore Other Categories