>>1838670For a replacement, there are three numbers to measure: steerer length, axle-crown distance, and rake. Ideally the new fork would match all three.
Measurements 1 and 2 are straightforward.
Steerer length (1) is distance from the top of the fork crown to the end of the steerer tube. In practice, measure from the bottom of the bearing race that's installed on the steerer. The diagram originally showed head tube length, but I drew the steerer measurement in green.
Axle-crown (2) is from the center of the fork end/axle location to top of the fork crown/underside of steerer bearing race.
Fork rake (3) is trickier, pic is one way to do it. Another is have the fork flat on a surface and butt the fork tips against a 90 degree surface. Mark A, then sight down the steerer and mark B. Imagine laying the fork on your kitchen counter, and using a marker to write A on the wall, then looking down through the tube and marking B, then measuring your marks on the wall to do A minus B.
For a style match, I'm sure you can get suggestions if you post a few pics of your current fork (one from the front, one from the side). Probably your country, too.
If you have a bike co-op near you, I'd check there first. I've picked up replacement forks at my local for dirt cheap. Measurements weren't exact, but they were close enough.
