Dark Mode in Google Sheets: The Ultimate Guide 
Dark mode is a feature that shows light text on a dark background. Because of the lower levels of blue light, it is more comfortable and better suited to dark environments. It can also appear as a more attractive alternative depending on the user and help improve device battery life.
Unfortunately on a PC environment dark mode is not an easy feature to enable; however, we have two different methods to do exactly that.
Google Sheets Dark Mode Desktop
Using add-ons is an efficient way to enable dark mode in a PC environment. There are several possible add-ons including:
Dark Mode - Night Eye
Dark Theme and Night Shift Mode
Dark Mode for Chrome
In this tutorial we are going to install the Dark Mode - Night Eye add-on.
Step 1: Open the Chrome web store
Access the Chrome web store by selecting the three dot symbol ⋮ at the top right hand side of the Chrome browser, select Settings. A new tab will open - select Extensions which can be located at the bottom of the left hand menu on this view.
The extensions tab will now appear, select the menu symbol ≡ on the top left hand side of the screen, this will present the extension menu. At the bottom of this select Open Chrome Web Store. The store will open in a new tab
Step 2: Search for the dark mode extension
In the search bar type “Dark Mode night eye” and press enter to see the search results
Step 3: Add the Dark Mode Extension to Chrome
Select the extension Dark Mode- Night Eye and click on Add to Chrome, a pop up window should now appear. Select Add Extension. The extension will now be added to the Chrome browser.
Step 4: Using the Dark Mode Add-on
With the extension now installed, open Google Sheets, select the extension by clicking on the jigsaw symbol at the top left hand corner of the screen and selecting the extension. In the extension pop up menu you will see the power button symbol. Finally select turn on to enable the theme.
Another method to use the Google Chrome browser to apply dark mode to Google sheets is to use chrome.flags
Please note that this method is experimental, may slow down your computer and can be used only on the Chrome browser.
Step 1: Access Experiments in Chrome
In a new browser window type chrome://flags/ in the URL bar and press enter to access the experimental features.
Step 2: Enable Auto Dark Mode for Web Contents
In the search bar at the top type“dark mode”. This will display the Enable Auto Dark Mode for Web Contents flag. Click the drop down menu on the right hand side labelled “Default” and set this to Enabled
Step 3: Restart browser to see results
A bar will appear at the bottom of the screen to relaunch the browser, select this and Chrome will restart. Navigate to Google Sheets to see the changes. The sheet remains white but the Menu ribbon, options, the slider, and the Sheet Names go into dark mode.
Google Sheets Dark Mode on Mobile
Turning on the Dark theme on an Android/mobile phone is a very easy task. With the Google Sheets application open on the device press the three dot symbol ⋮ at the top right hand side of the application and select View in dark theme. As simple as that the theme turns to the dark theme.