Tool

Headlight aim calculator

The estimate uses drop = distance × tan(angle). Height can be inches or centimeters. Distance to the wall can be feet or meters and is converted to inches before the tangent. The figure is trigonometry from your numbers, not a service aiming procedure.

Tap Example to fill a compact sedan at a 25 ft wall. Use those fields as a scale, then replace them with your tape.

Units on the tape

Inches and feet Centimeters and meters

Lamp height (inches)

Measure from the floor to the center of the lamp.

Distance to the wall (feet)

A common garage check uses 25 ft.

Which number do you already have?

I measured drop on the wall I have an angle in degrees

Beam drop (inches)

How far the cutoff sits below lamp height on the wall.

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Enter height, distance, and either drop or angle. The estimate will name inches and degrees in a full sentence.

The last numbers stay in this browser. A copied link opens the same fields.

Lamp, beam, and cutoff. The line moves after you estimate. This sketch is not a shop screen.

This figure is an educational estimate. It is not a product listing, not DOT or SAE certification, and not legal advice on aftermarket lamps. Aiming and wattage do not make a lamp street-legal. Check the vehicle manual and local law.

When this estimate fits

You have a tape on a flat wall and a square floor, and you want the geometry of drop versus angle.
You are comparing two numbers you already measured, not asking the page to aim the car for you.
You accept that a phone estimate is not a shop procedure and does not certify the lamp.

Worked numbers from this formula

At 25 ft, a 2 in drop is about 0.38°. Is that the drop you taped on the wall?

A 26 in lamp height with a 2 in drop puts the cutoff near 24 in. Does the tape on the wall agree?

If drop is left at 0, the calculator stops at the field. A level beam is not treated as a finished estimate.

Questions

Is this the same as a shop aiming chart?

No. The calculator only converts the height, distance, and drop or angle you enter. A shop procedure uses the vehicle manual and a calibrated screen.

Which way is drop?

Drop is downward. A cutoff line below lamp height is a positive drop. The estimate does not treat an upward beam.

Why inches and feet together?

Lamp height and drop are taped in inches. Distance to the wall is usually walked off in feet. The calculator multiplies feet by 12 before the tangent.

Open the wall-chart helper if you already know the cutoff line height. Read the aiming guide for the same limits in prose.