How to Create a Calculator Using Power Apps

Power Apps Canvas Apps allow developers to build interactive business applications with minimal code. One of the best ways to learn Power Apps controls, variables, and Power Fx formulas is by creating a simple calculator application.

In this tutorial, you'll learn how to create a calculator that performs basic arithmetic operations such as addition, subtraction, multiplication, and division.

Why Build a Calculator in Power Apps?

Learn Power Fx formulas
Understand variables and controls
Practice Canvas App development
Build interactive user interfaces
Improve Power Apps skills

Create the User Interface

Add the following controls to your Canvas App:

Label for displaying results
Buttons for numbers 0–9
Buttons for arithmetic operators
Clear button
Equals button

Store User Input

Use variables to store numbers and operators.

Set(varValue, "");
Set(varOperator, "");

Configure Number Buttons

For each number button, append the selected digit.

Set(
   varValue,
   varValue & "1"
)

Replace "1" with the corresponding number for each button.

Configure Operator Buttons

Store the selected operator and first value.

Set(varFirstNumber, Value(varValue));
Set(varOperator, "+");
Set(varValue, "");

Calculate the Result

Use the Equals button to perform the calculation.

If(
   varOperator = "+",
   Set(varResult,
       varFirstNumber + Value(varValue)
   )
)

You can extend the formula to support subtraction, multiplication, and division.

Important: Always validate division operations to prevent divide-by-zero errors.

Display the Result

Bind the label Text property to the result variable.

varResult

Common Enhancements

Add decimal support
Implement percentage calculations
Create scientific calculator functions
Add keyboard support
Improve UI with modern controls
Store calculation history

Best Practices

Use meaningful variable names.
Validate user inputs.
Handle division-by-zero scenarios.
Keep formulas readable.
Test all calculation paths thoroughly.

Key Takeaways

Power Apps can be used to create interactive calculators.
Variables store user inputs and operators.
Power Fx formulas perform calculations.
Canvas Apps provide a flexible UI for custom tools.
Building a calculator is an excellent Power Apps learning exercise.