Print this page before you start. Screens come in every size, so reading the chart on your phone or monitor will not give you the right answer. Print it at 100% with "fit to page" turned off, then check the card ruler at the top.
Opens in a new tab. Print it, or save it to your device from there.
This is a guide for choosing non-prescription readers, not an eye test. It cannot detect an eye condition or replace a proper prescription. If your eyes have changed suddenly, or each eye is different, see an optometrist.