Find the equation of a line perpendicular to a given line and passing through a point.
Last updated: June 2026 | By Patchworkr Team
Original slope is required.
Perpendicular slopes are negative reciprocals. If the original slope is 0, the perpendicular line is vertical.
For original slope 2 and point (1, 3), the perpendicular slope is -1/2 and the line is y = -0.5x + 3.5.
What if the original slope is zero?
The perpendicular line is vertical, so x stays constant.
Can the perpendicular slope be positive?
Yes, if the original slope is negative.
Does blank input count as zero?
No. Blank input is treated as missing, not zero.
What if the original line is vertical?
This calculator does not accept undefined slope as input.
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