DIY Custom Formula Calculator

Simply define your formula using variables (like A, B, C), add those variables with values, and click calculate. Use presets for common formulas or build completely custom calculations for any purpose.

This calculator includes advanced voice input - click the microphone icon next to any variable to speak numbers instead of typing. Perfect for hands-free calculations and accessibility.

The calculator supports all standard arithmetic operations (+, -, *, /, ^), trigonometric functions (sin, cos, tan), logarithmic functions, square roots, absolute values, and many more through the math.js library. You can use parentheses for complex expressions and nesting.

Yes! Click the microphone button next to any variable input field to use voice recognition. Speak the number clearly, and the calculator will convert your speech to text and populate the field. This requires microphone permissions in your browser.

This calculator is incredibly versatile! Use it for: financial calculations (interest, loans), scientific formulas, engineering calculations, statistical analysis, unit conversions, recipe scaling, DIY project planning, educational purposes, and any custom calculation you can imagine. The presets provide common starting points.

Calculations are performed using the math.js library, which provides high-precision mathematical operations. The accuracy is limited by JavaScript's floating-point precision, but for most practical purposes, it's extremely accurate. Complex calculations and very large/small numbers are handled appropriately.