WhatsApp is a cross-platform messaging app that allows users to communicate over 4G or Wi-Fi without having to pay to send a text message. If you find the font size too big or too small, you can adjust it to your own preference. If you're on iOS, you can make your changes through your iOS settings, while Android users can change the font size from within the app itself.
Method 1 of 2: iOS
Step 1. It is no longer possible to change text size from WhatsApp app
Instead, resize using iOS's built-in text resizing options.
Step 2. Select 'Chat Settings'
If you're using iOS 7, select "General."
Step #3. Tap on the 'Text Size' option
Step 4. Drag the slider to adjust the size of the text
Dragging it to the left will make WhatsApp's text size smaller, sliding it to the right will make it larger.
Step 5. Open 'Settings' → 'General' → 'Accessibility' → 'Larger Text' to enable very large text
This is useful if you have trouble reading smaller text.
Method 2 of 2: Android
Step 1. You can change WhatsApp font size from WhatsApp settings
Step 2. Tap the menu button (⋮) and select 'Settings'
You can find this in the top right corner.
Step #3. Tap on 'Chat Settings'
Step 4. Tap on 'Font Size' and select the size of the desired font
There are three options to choose from with 'Medium' being the default size.