All Math & Converters Tools
Aspect Ratio Calculator
Calculate missing width, height, or ratio instantly — with visual preview and common presets
Binary / Hex / Decimal / Octal Converter
Convert numbers between binary, hexadecimal, decimal, and octal instantly
Bra Size Calculator
Calculate your US, UK, EU, and AU bra size from band and bust measurements with sister sizes
Free Percentage Calculator
Calculate percentages, percentage change, and more instantly
Free Tip Calculator & Bill Splitter
Calculate tips, split bills, and see a full breakdown instantly
Morse Code Translator
Convert text to Morse code and back instantly with audio playback
Number to Words Converter
Convert any number to English words instantly — standard, ordinal, check, or currency format
Price Per Unit Calculator
Compare products by cost per unit to find the best deal every time
Ring Size Calculator
Convert ring sizes between US, UK, EU, and Asian systems or find your size from a finger measurement
Roman Numeral Converter
Convert between numbers and Roman numerals — supports 1 to 3999
Shoe Size Converter
Convert shoe sizes between US, UK, EU, and JP/CM systems for men, women, and children instantly
Shrinkflation Calculator
Compare old vs new product sizes to uncover hidden price increases through shrinkflation
Sports Betting Parlay Calculator
Calculate parlay odds, payouts, and implied probability for 2-15 leg accumulators
Text Case Converter
Instantly convert text to UPPERCASE, lowercase, Title Case, camelCase, snake_case, and more
Tiny Text Generator
Convert text to superscript, subscript, and small caps Unicode characters instantly
Unit Converter
Instantly convert between common units of length, weight, temperature, volume, area, speed, time, and data
Upside Down Text Generator
Flip your text upside down, mirror it, reverse it, or fully rotate it 180° using Unicode characters
Zalgo Text Generator
Transform normal text into creepy, glitchy Zalgo text with combining diacritical marks
Math & Converters on FastTools are free, browser-based tools designed to help you get quick answers without signups or downloads. Every calculator runs entirely in your browser — your data never leaves your device.
Whether you're planning, budgeting, or just curious, these tools are built to be fast, accurate, and private. Pick any tool below to get started instantly.
Frequently Asked Questions
Are these math & converters free?
Yes, every tool is completely free to use with no signup, no account, and no hidden fees.
Is my data safe?
Absolutely. All calculations run locally in your browser. No data is sent to any server or stored anywhere.
Do I need to create an account?
No. Every tool works instantly with no registration required. Just open and start using.