How big is the International Space Station?
NASA describes the ISS as 109 meters end-to-end, one yard short of the full length of an American football field including the end zones. That is one of the most useful comparisons in modern spaceflight because it takes something abstract — an orbiting laboratory — and turns it into a sports-field-sized object flying above Earth.
Its altitude is roughly 400 km, so you get a double comparison: a football-field-sized structure, but placed hundreds of kilometers overhead.
Length
109 meters end-to-end.
Altitude
About 400 km above Earth.
Best mental image
A football field in orbit.