Height gives an average, measuring gives your number
The height method uses the common rule of thumb: step length is about 0.413 of height for women and 0.415 for men. It is an average across many people. Your own step can be ten centimetres either side of it, which on 10,000 steps is the difference of about 0.6 miles.
Measuring takes a minute. Walk ten normal steps on a floor with a tape or a known length, measure from the heel of the first step to the heel of the last, and divide by ten. Walk the way you usually walk. People measuring themselves tend to stride out, and that makes the answer too long.