Start with Font size when the words are the problem; compare Display size when the whole interface feels too small. Make one change at a time, then judge both readability and whether the complete content still fits.
Find the two controls
In Settings, search Font size or Display size and adjust its slider. Some steps require Android 13 or later; some apps ignore font size. Preview and reset options are documented in Google's display guidance.
Before adjusting anything, note the original slider position. Choose a read-only help page rather than an account or payment screen. For a practical comparison, identify three things to revisit: one paragraph, one ordinary button label and a label inside the phone's Settings. That gives you specific observations instead of a general impression that everything looks bigger.
Compare one hypothetical result
Imagine that after changing Font size, the help paragraph is easier to read, its button label is unchanged, and the Settings label is larger. Record those outcomes separately. Do not mark the whole change “failed” just because one item did not respond.
Now suppose the page also contains an image with lettering that looks unchanged. That observation is about the image, not proof that the larger paragraph returned to its old size. Leave the image result in its own row. Restore the initial setting before making a separate Display size comparison, so you know which adjustment produced each result.
Check fit before keeping the change
For each observation, answer two questions: can you read the words comfortably, and can you still see the complete label or reach the end of the paragraph? A larger but clipped label is not an improvement in both respects. In that hypothetical case, restore the original position or compare a smaller adjustment.
Keep the choice that helps with your actual reading task, not merely the largest setting. Our screen-change checklist covers general comparison habits; it does not establish how a particular game app supports either Android setting.