Can I use decimals in the basic calculator?

Yes. The calculator supports decimal values for all operations.

What happens if I divide by zero?

The tool returns a safe validation error because division by zero is undefined.

Is modulo available for negative values?

Modulo operation is supported and follows backend math rules for float values.

Can I calculate square root with the basic calculator?

The basic calculator covers addition, subtraction, multiplication, division, modulo, and power. For square root and trigonometry, use the Scientific Calculator.

Is there a history of calculations?

The current version shows the last computed expression. For running history, note down results between operations.

Basic Calculator Online - Free Arithmetic Calculator

Why use this Basic Calculator

Built for speed, clarity, and SEO depth.

The Basic Calculator Online lets you perform instant arithmetic calculations free on any device. It supports addition, subtraction, multiplication, division, modulo, and power operations with decimal precision. Whether you need a quick arithmetic calculator for homework, invoice checking, or shopping comparisons, this tool returns clean results with an expression readout so you can verify exactly what was computed. The interface is intentionally minimal — no signup, no download, no clutter. It works on mobile and desktop equally well, making it the fastest free calculator online for everyday tasks. The formula reference below documents how each operation works mathematically, and the FAQ answers common questions about decimal support, division by zero handling, and negative number behaviour.

Basic Arithmetic Formula Reference

Use these formulas to verify calculator output manually.