What is a Binary Tree Visualizer?
A binary tree visualizer is an interactive tool that turns level-order array input into a tree diagram. It is useful when you want to understand a tree’s shape, compare traversal orders, or check coding interview examples that use null placeholders.
This visualizer supports LeetCode-style input such as [1, 2, 3, null, 4]. The values are read from left to right, level by level, and null marks a missing child.
For the full set of related learning tools, start with the Data Structure Visualizers hub.
How to use the binary tree visualizer
- Paste a level-order array into the input box.
- Use
nullfor missing left or right children. - Click Build to render the binary tree.
- Run in-order, pre-order, post-order, or level-order traversal.
- Copy the traversal output if you want to compare it with your code.
For example, [1, null, 2, 3] means the root is 1, the root has no left child, the root’s right child is 2, and 2 has a left child 3.
Binary tree vs binary search tree
A binary tree is any tree where each node has at most two children. The left and right child positions matter, but there is no automatic ordering rule.
A binary search tree is a special kind of binary tree. In a BST, smaller values go to the left and larger values go to the right. If you want that ordering behavior, use the Binary Search Tree Visualizer.
If you want a tree that automatically keeps itself balanced, compare this with the AVL Tree Visualizer. If you want priority-queue behavior instead of tree search, use the Heap Visualizer.
Common binary tree traversal orders
In-order traversal visits the left child, then the current node, then the right child.
Pre-order traversal visits the current node before visiting its children.
Post-order traversal visits both children before visiting the current node.
Level-order traversal visits the tree breadth first, from top to bottom and left to right.