about my battery health

Update to the latest software.

Always make sure your MacBook is using the latest version of macOS. If you’re connected to the Internet, macOS automatically checks for software updates every week, but you still control when the updates are installed. To confirm that you’re using the latest software, go to the Apple menu and choose Software Update.

Learn more about updating macOS

Optimize your settings.

Energy. The Energy Saver preference pane includes several settings that determine power levels for your MacBook. Your MacBook knows when it’s plugged in and runs accordingly. When using battery power, it dims the screen and uses other components sparingly. If you change this setting to maximize performance, your battery will drain more quickly.

Brightness. Dim the screen to the lowest comfortable level to achieve maximum battery life. For instance, when watching a video on an airplane, you may not need full brightness if the cabin lights are off.

Wi-Fi. Wi-Fi consumes power, even if you are not using it to connect to a network. You can turn it off in the Wi-Fi status menu in the menu bar or in Network preferences.

Applications and peripherals. Disconnect peripherals and quit applications not in use. Eject an SD card if you’re not currently accessing it.

Plug in and power on your MacBook to charge other devices.

Make sure your MacBook is plugged in and powered on when you’re using it to charge other devices via USB. Otherwise those devices may drain the battery in your MacBook faster than normal. If another device is connected to your MacBook when it’s turned off or in sleep or standby mode, the device’s battery may drain.

Depends on what you're doing with it. Some web browsing, email, or typing a letter isn't going to use as much as playing a game or video editing.

The battery times that are advertised are usually based on some very specific metrics. Like the screen brightness is turned down past 50% and playing music that is already downloaded to the hard drive with all other features turned off.

If you're seeing the battery decrease without doing much, I'd check your activity monitor and see if there are any background programs going wild. Go to the launchpad, and search for "activity monitor" at the top. This will give you a list of what programs are hogging up the most resources.