To add to your 'Ctrl +' and 'Ctrl - references', remember that 'Ctrl 0' automatically reverts to your default size.
Your post clearly implies that you're referring to the text size in your browser (rather than in any other program) but you've forgotten to say which browser you're using!
In Firefox, for example, you can click the 'hamburger' symbol (with 3 horizontal lines) at the top right of your screen. Then click on Options and next onto Content. Under Fonts & Colours, click on Advanced. Increase the font sizes shown and remove the tick allowing pages to select their own font sizes.
Alternatively you can make everything on your screen look bigger by simply dropping the screen resolution slightly. See 'Getting the best display on your monitor' here to find out how to access the settings (and then simply drag the slider slightly to the left before clicking on Apply).