Infix to postfix

The Shunting Yard

Dijkstra named the algorithm after a railroad yard. Numbers ride the output track. Operators wait on a siding until precedence says they may leave.

Expression

Mathematical expression

Angles for sin, cos, tan

Conversion 1 / 1

Postfix

Input

Siding

Output

Remaining

Value stack

Ready.

Result

Enter parses. Right arrow steps. Space plays. Escape resets.

Open-source math tool. MIT License.

Infix writes operators between values, as in 3 + 4 × 2. Postfix writes them after, as in 3 4 2 × +, so a stack can evaluate without parentheses. Unary minus appears as neg.