How to compare battery use in light and dark mode

You switch to dark mode to make a screen easier on your eyes, or to make your battery last longer. But the battery can drain at different rates because of brightness, apps, and background activity, so a quick glance at the percentage may not tell you whether dark mode helped.

Use the Battery Meter to compare the reported drain rate under similar conditions. It reads battery information your browser makes available, so you can check the same device in both modes without installing anything.

Compare battery use in both modes

1. Open the Battery Meter on the laptop, tablet, or phone you want to check. The tool appears only if your browser reports a battery. Note the charge level and whether the device is charging.
2. Set the device to light mode. On Windows 11, open Settings › Personalization › Colors › Choose your mode. On macOS, use System Settings › Appearance › Light. On an iPhone, open Settings › Display & Brightness › Light. On many Android devices, use Settings › Display › Dark theme and turn it off. Menu names can vary by phone maker.
3. Unplug the device and set a fixed screen brightness. Turn off automatic brightness if you can, close unrelated apps, and keep the same Wi-Fi connection and peripherals for both runs. Wait a few minutes after unplugging so the initial drain from startup or background tasks can settle.
4. Use the device for 30 to 60 minutes in a consistent way. For example, keep the same webpage open and scroll or read at a similar pace. Note the starting and ending charge levels and the drain rate shown by the Battery Meter.
5. Switch to dark mode and repeat the same activity at the same brightness for the same length of time. Compare the meter's drain rate and the amount of charge used. If you can, repeat each mode once and compare the averages.

Keep the browser tab open while measuring. Do not compare a light-mode video session with a dark-mode session where the device is idle. The display mode should be the main change between runs, not the activity or brightness.

What the result means

Dark mode shows a lower drain rate

The device used less battery during that run, but the result does not prove that the screen theme caused the full difference. Background tasks and small changes in activity can affect the reading. If a second matched run shows a similar difference, dark mode may be reducing power use on your device.

The drain rate is about the same

Dark mode may not make a measurable difference in your setup. This is common on screens that use a backlight, and the difference can also be too small to distinguish from ordinary variation in a short test. You can still use dark mode for comfort or preference.

Dark mode shows a higher drain rate

That does not necessarily mean dark mode uses more power. A background update, a brighter screen, a changed app workload, or a different wireless signal may explain the result. Repeat the test with the same brightness and workload before drawing a conclusion.

The percentage or rate jumps around

Battery readings are estimates, and the displayed charge level may change in whole percentage points. A short test can be too brief to reveal a small difference. Run each mode longer, avoid using the device for unrelated tasks, and compare more than one run.

Why dark mode may not save much battery

The screen type matters. On an OLED screen, each pixel produces its own light, so black or very dark areas can use less power than bright areas. The amount saved depends on how much of the screen is dark and how bright the pixels are. A dark background with bright text may use less display power than a mostly white page, but dark mode does not turn the screen off.

Many LCD screens use a backlight behind the whole display. Changing the colors on the screen usually does not switch off that backlight, so dark mode may have little effect on display power. Reducing brightness can matter more on these screens.

The app or website must also actually show dark colors. An operating system's dark appearance setting does not force every page to change. If the page stays white, the test is not comparing a dark screen with a light one. Check that the same content is visibly dark in the second run.

The Battery Meter reports the battery information available to the browser, including charge level, charging state, time left, and drain rate. It does not measure the screen's power use separately from the processor, wireless connection, or other components. Treat it as a practical comparison of total battery use on your device, not a laboratory measurement of the display alone.