Endpoint Calculator

Find missing endpoints, midpoints, or starting points of line segments

Calculation Mode

What do you want to find?

Starting Point A (x₁, y₁)

Midpoint M (x, y)

Calculation Results

(8, 108000)
Missing Endpoint
Coordinates in (x, y) format
108000.0003
Segment Length
Total distance between endpoints
Formula used: B = (2x - x₁, 2y - y₁)
Half-segment length: 54000.0001

Step-by-Step Solution

Step 1: Identify the known values
Starting point A = (0, 0)
Midpoint M = (4, 54000)
Step 2: Apply the endpoint formula
Endpoint B = (2×midX - startX, 2×midY - startY)
Step 3: Substitute the values
x₂ = 2×4 - 0 = 8 - 0 = 8
y₂ = 2×54000 - 0 = 108000 - 0 = 108000
Step 4: Write the final answer
Endpoint B = (8, 108000)
Step 5: Verify the calculation
Distance AM = √[(4-0)² + (54000-0)²] = 54000.0001
Distance MB = √[(8-4)² + (108000-54000)²] = 54000.0001
✓ Both distances are equal, confirming M is the midpoint

Example Calculation

YouTube Channel Growth Example

Problem: You started a YouTube channel 4 months ago with 0 subscribers. Now you have 54,000 subscribers. If growth continues linearly, how many will you have in 4 more months?

Starting point: Month 0, 0 subscribers → A = (0, 0)

Current position (midpoint): Month 4, 54,000 subscribers → M = (4, 54000)

Goal: Find endpoint at month 8

Solution

Step 1: Use endpoint formula: B = (2x - x₁, 2y - y₁)

Step 2: Substitute values: B = (2×4 - 0, 2×54000 - 0)

Step 3: Calculate: B = (8, 108000)

Result: You'll have 108,000 subscribers in month 8!

Formula Reference

Find Endpoint

B = (2x - x₁, 2y - y₁)

Given: Starting point A(x₁,y₁) + Midpoint M(x,y)

Find Midpoint

M = ((x₁+x₂)/2, (y₁+y₂)/2)

Given: Starting point A(x₁,y₁) + Endpoint B(x₂,y₂)

Find Starting Point

A = (2x - x₂, 2y - y₂)

Given: Midpoint M(x,y) + Endpoint B(x₂,y₂)

Quick Tips

The midpoint is exactly halfway between two endpoints

Distance from start to midpoint = Distance from midpoint to end

All three points (start, mid, end) lie on the same straight line

Works for any coordinate system (negative numbers allowed)

Useful for linear growth predictions and geometry problems

Understanding Endpoints and Midpoints

What is an Endpoint?

An endpoint is a point that lies at the end of a line segment. Every line segment has exactly two endpoints (unless it's a degenerate case where both endpoints are the same point). Endpoints define the boundaries of the segment.

What is a Midpoint?

A midpoint is the point that lies exactly in the middle of a line segment. It divides the segment into two equal parts. The distance from one endpoint to the midpoint equals the distance from the midpoint to the other endpoint.

Real-World Applications

  • Linear growth prediction (business, population)
  • Finding center points in construction
  • Navigation and GPS coordinates
  • Computer graphics and animation

Mathematical Properties

Symmetry: If M is the midpoint of AB, then AM = MB

Collinearity: Endpoints and midpoint lie on the same line

Reversibility: Any of the three points can be calculated from the other two

Geometric Interpretation

When you have a line segment, the midpoint creates two smaller segments of equal length. This property is fundamental in geometry and has applications in coordinate geometry, vector mathematics, and analytic geometry.

Key Insight: The endpoint formula essentially "reflects" one endpoint across the midpoint to find the other endpoint. This is why we multiply the midpoint coordinates by 2 and subtract the known endpoint.

Common Use Cases

Business Growth

Predict future values based on linear growth patterns

  • • Revenue forecasting
  • • Customer acquisition
  • • Market expansion
  • • Performance metrics

Engineering & Design

Find center points and balance points in construction

  • • Structural center points
  • • CAD design
  • • Architecture planning
  • • Load distribution

Navigation & Mapping

Calculate intermediate points and destinations

  • • GPS waypoints
  • • Route planning
  • • Geographic analysis
  • • Location services