How can I measure something if I don't have a ruler or tape measure handy?

Most modern smartphones include a built-in measurement app that uses the camera and AR to estimate distances and object dimensions with reasonable accuracy.

Manufactured items have standardized dimensions, making them surprisingly reliable stand-in rulers. Keep a few key sizes memorized and you can estimate most everyday measurements.

Your body is always with you, making it a convenient rough measuring tool. For best results, measure your own hand span, foot, and finger against a real ruler once, then memorize those numbers.