A* Pathfinding Visualizer

Draw obstacles, add weighted terrain, move the start and end nodes, then watch A* combine the travelled cost g(n) with the estimated remaining cost h(n).

Search metrics

Visited nodes0

Path cost—

Open set0

Path length—

Ready. Draw walls or press Run A*.

Legend

Start

Goal

Wall

Cost 5

Open set

Closed set

Final path

How A* works

openSet = { start }

while openSet is not empty:
  current = node with lowest f

  if current is goal:
    return reconstructed path

  move current to closedSet

  for each neighbor:
    tentativeG = current.g + moveCost

    if tentativeG is better:
      neighbor.parent = current
      neighbor.g = tentativeG
      neighbor.h = heuristic(neighbor, goal)
      neighbor.f = neighbor.g + neighbor.h
      add neighbor to openSet

Controls

Click and drag to paint walls, erase cells, or add weighted terrain. Choose “Move Start” or “Move End,” then click a new cell. “Step” advances one search iteration at a time.