What is the altitudeof the bottom of the stratosphere?

The bottom of the stratosphere typically begins at an altitude of about 10 to 15 kilometers (approximately 6 to 9 miles) above sea level. This boundary, known as the tropopause, varies depending on geographic location and weather conditions, being lower at the poles and higher at the equator. The stratosphere extends from this point up to about 50 kilometers (31 miles) in altitude.