Parallel Line Calculator

Parallel Line Calculator

Find the equation of a line parallel to a given slope and passing through a point.

Last updated: June 2026 | By Patchworkr Team

Parameters

Slope is required.

Results
Enter a slope and a point to build the parallel line.

How It Works

Parallel lines share the same slope. Once the slope is known, use the point to solve for the y-intercept.

Formula

Point-Slope
y - y1 = m(x - x1)
Slope-Intercept
y = mx + b

Example

Parallel to y = 2x, through (3, 4): b = 4 - 2(3) = -2.

y = 2x - 2
check: 4 = 2(3) - 2

FAQ

Do parallel lines have the same slope?

Yes. Matching slopes is the defining property of parallel lines.

Can a parallel line be vertical?

Yes. Vertical lines are parallel to other vertical lines.

Does blank input count as zero?

No. Blank input is treated as missing, not zero.

Can the intercept be negative?

Yes. That is completely normal.

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