What does Dijkstra's algorithm compute?

It finds the shortest-distance path from a given start node to a given end node (or to every node) in a weighted graph, where 'shortest' means the minimum total edge weight along the path.

Why does Dijkstra's algorithm require non-negative weights?

The algorithm assumes that once a node is visited with its minimum distance, that distance can never improve later — a negative-weight edge could violate that assumption, requiring a different algorithm (like Bellman-Ford) instead.

How do I enter my graph?

As a comma-separated list of edges in the form NodeA-NodeB:weight, like A-B:4, B-C:2 — each edge is treated as undirected (traversable in both directions) with the given weight.

What happens if there's no path between the start and end nodes?

The calculator reports that no path exists, rather than an incorrect distance — this happens when the two nodes are in different disconnected components of the graph.

Can I use this for an unweighted graph?

Yes — just give every edge the same weight (like 1), and the shortest weighted path becomes equivalent to the shortest path by number of edges (a breadth-first search result).

How many nodes can this calculator handle?

This calculator supports up to 50 nodes, which keeps the straightforward O(V²) implementation fast while covering the vast majority of hand-entered graph examples.

Where is Dijkstra's algorithm used in real life?

It's the conceptual foundation of GPS and mapping software, network packet routing (like OSPF), flight connection search engines, and any system that needs the cheapest path through a weighted network.

How is this different from the Minimum Spanning Tree Calculator?

Dijkstra's algorithm finds the cheapest path between two specific nodes, while a minimum spanning tree connects every node in the graph as cheaply as possible overall — related goals, but answering different questions.

Dijkstra's Shortest Path Calculator — Find the Shortest Route Between Two Nodes

Our Dijkstra's Shortest Path Calculator finds the shortest path between any two nodes in a weighted graph, entered as a simple text edge list (e.g. A-B:4, B-C:2), using Dijkstra's classic shortest-path algorithm — the same technique that powers real-world routing and network systems.

Quick Answer

Enter your weighted graph as an edge list and pick a start and end node to instantly find the shortest path and total distance via Dijkstra's algorithm.

Edges (comma-separated)

Enter weighted edges as NodeA-NodeB:weight, e.g. A-B:4, B-C:2.

Start node

End node

How to Use the Dijkstra's Shortest Path Calculator — Weighted Graphs Online

1
Enter your graph as a comma-separated edge list, e.g. A-B:4, B-C:2.
2
Enter the start and end node names.
3
Click 'Calculate' to find the shortest path and total distance.

Why Use Dijkstra's Shortest Path Calculator — Weighted Graphs Online?

Dijkstra's algorithm, devised by Edsger Dijkstra in 1956, finds the shortest path from a starting node to every other node in a weighted graph by repeatedly visiting the closest unvisited node and relaxing (updating) the distances to its neighbors — a greedy approach that's provably optimal as long as edge weights are non-negative. This exact algorithm, or close variants of it, underlies GPS navigation, network routing protocols, and countless pathfinding systems, and this calculator runs it directly on a graph you describe as a simple weighted edge list.

Frequently Asked Questions

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