Aiming headlights

A garage wall can show whether a cutoff sits high or low. It cannot replace the aiming procedure in the vehicle manual. Auto Car Lighting Lab estimates drop and angle from the numbers you type. The estimate is trigonometry, not a shop ticket.

What the numbers mean

Lamp height is the distance from the floor to the center of the lamp. A US tape reads that in inches; the aiming tools can also take centimeters. Wall distance is usually walked off in feet, or in meters if you switch units. Drop is how far the cutoff sits below lamp height on the wall. Angle follows from drop = distance × tan(angle), after the distance is converted to inches.

A worked example: at 25 ft, a 2 in drop is about 0.38°. A 26 in lamp with that drop puts the cutoff near 24 in. Those figures match the aim calculator and the wall-chart helper.

What a phone estimate cannot do

The calculator does not know the vehicle’s specified drop. It does not level the car, set tire pressure, or place a rider in the seat. It does not certify a lamp. A cutoff that looks tidy on a painted wall can still glare or leave the road dark if the housing is twisted or the lamp is the wrong type.

A cautious garage check

Park on level ground. Point the car square at a flat wall. Measure lamp height and the distance you actually used. Mark a line if you want the wall-chart layout. Compare the cutoff you see with the drop you intended. If the two disagree, the next step is the manual or a shop with a screen—not a second guess from this article.

Units on this site

The default is inches and feet, because that is how a US tape reads on a garage floor. Each aiming tool also has a centimeters-and-meters choice. The formula still converts distance to inches internally. Miles do not belong in a 25 ft wall check.

Read the aftermarket lamps note if the housing or bulb is not original. Aiming a lamp does not make the lamp street-legal.