Free Online Tools & Calculators
973 free calculators, converters, generators and tools for everyday work, study, and creative projects.
Popular tools
Online Whiteboard
Free online whiteboard — no account, no uploads, nothing stored. Draw in your browser, export PNG. No Miro account required, no sign-up, works instantly and privately.
Molarity Calculator
Calculate molarity, mass, volume, molecular weight, stock dilution, or molarity from g/L, ppm, ppb, and % w/v. Shows worked steps instantly.
Fraction Pizza
Free interactive fraction visualizer for kids and classrooms. Click pizza slices to fill them and instantly see the fraction, decimal, and percent. Includes equivalent fractions, compare mode, challenge packs, printable worksheets, and colorblind-safe themes. No login, works in browser.
Time Since/Until
Find how long ago a past date was, count down to a future date, or compare two dates with calendar and total elapsed time results.
Image & Graphics
(13 tools)- Compress Images
- Image Resizer & Converter
- Crop Image
- QR Code Generator
- Add Text to Image Online Free
- Add Watermark to Image Online Free
PDF & Documents
(18 tools)- Merge PDF Files
- Split PDF
- Compress PDF Online Free
- Markdown to PDF Converter
- PDF to Text Converter
- Add Page Numbers to PDF
Text & CSV
(12 tools)- Case Converter
- Word Counter
- Find and Replace Text
- CSV Viewer
- Compare Text Online with a Free Diff Checker
- Duplicate Line Remover
Web Development
(34 tools)- URL Encoder & Decoder
- Markdown to HTML Converter
- CSS Formatter, Minifier & Beautifier
- Online JavaScript Minifier & Beautifier
- JSON Formatter & Validator
- Base64 Encoder & Decoder
Finance Calculators
(108 tools)- Compound Interest Calculator
- Loan Calculator
- Mortgage Repayment Calculator
- Savings Goal Calculator
- Investment Goal Calculator
- APR to APY Calculator
Math & Geometry
(52 tools)- Circle Calculator
- Triangle Calculator
- Pythagorean Triple Generator and Checker
- Ellipse Calculator
- Distance Between Two Points Calculator
- Slope Calculator
More tool categories
Explore the rest of the library. Counts update as new tools are published.
Health & Fitness
(25 tools)- Army Body Fat Calculator
- Basal Metabolic Rate
- Blood Pressure Calculator
- BMI Calculator - Body Mass Index and Healthy Weight Range
- BMI vs Body Fat Calculator
- Body Surface Area Calculator
Statistics & Probability Calculators
(18 tools)- Average
- Bayes’ Theorem Calculator
- Binomial & Poisson Distribution Calculator
- Confidence Interval Calculator
- Correlation Coefficient Calculator
- Expected Value Calculator
Algebra & Equation Calculators
(30 tools)- Absolute Value Equation and Inequality Calculator
- Arithmetic or Geometric Sequence Calculator
- Bilinear Interpolation Calculator
- Combine Like Terms Calculator
- Comparing Fractions Calculator
- Completing the Square Calculator
Discrete Mathematics Calculators
(32 tools)- Adjacency Matrix Generator & Calculator
- Binary Relation Properties Calculator
- Bipartite Graph Checker and Two-Coloring Visualizer
- Boolean Algebra Simplifier with Truth Table
- Breadth-First and Depth-First Search Graph Visualizer
- Cartesian Product Calculator
Linear Algebra & Matrix Calculators
(30 tools)- 2D Rotation Matrix Calculator
- Angle Between Two Vectors Calculator
- Change of Basis Matrix Calculator
- Cholesky Decomposition Calculator with Steps
- Coordinate Transformation Calculator
- Cross Product Calculator for 3D Vectors
Calculus Calculators
(24 tools)- Aitken Delta-Squared Sequence Acceleration Calculator
- Arc Length Calculator
- Derivative Calculator with Free Steps and Graph
- Differential Equation Calculator and ODE Solver
- Directional Derivative Calculator
- Hessian Matrix and Critical Point Calculator
Number Theory Calculators
(18 tools)- Common Factor Calculator
- Continued Fraction Calculator and Rational Approximation Tool
- Coprime Number Checker & Pairwise Coprime Calculator
- Divisibility Test Calculator with Rules and Steps
- Divisor Count and Sum of Divisors Calculator
- Euler’s Totient Function Calculator with Steps
Calculators
(21 tools)- AC Power Calculator
- Acres to Square Feet Calculator
- dBm to Watts Calculator
- Decimal Degrees to DMS Converter
- Dilution Calculator
- Fabric Yardage Calculator for Sewing, Curtains, Cushions and Rectangular Pieces
Construction Tools
(37 tools)- Air Conditioner BTU Calculator
- Asphalt Calculator
- Baluster and Spindle Spacing Calculator
- Baseboard Calculator
- Brick and Mortar Calculator
- Caulk Calculator
Automotive & EV Calculators
(33 tools)- Alternator Size Calculator
- Battery Reserve Capacity to Amp Hours Calculator
- Brake Bias Calculator
- Brake Pad Life Calculator
- Car Depreciation Calculator by Year, Mileage and Vehicle Type
- Car Paint Calculator
Time & Date Tools
(36 tools)- Age Calculator
- Age Difference Calculator
- Age in Weeks and Months Calculator
- AOE Calculator
- Apple Cocoa / Core Data Time Converter
- Birthday Countdown Calculator
Science & Research Tools
(87 tools)- Acceleration Conversion Calculator
- Acid–Base Titration Calculator
- Acoustic Impedance Calculator
- Advanced Redshift and Cosmology Calculator
- Ant Colony Simulator
- Astronomical Unit Converter and Astronomical Distance Converter
Studio Tools
(50 tools)- Acoustic Treatment Calculator
- Anamorphic Squeeze & Desqueeze Calculator
- Aspect Ratio Calculator
- Audio Bit Depth Calculator
- Audio Crossover Calculator
- Audio File Size Calculator
Random Generators
(26 tools)- Bingo Card Generator
- Color Palette Generator
- Create a Sky Map for Any Date and Place
- Dice Roller
- Flip a Coin
- Kaleidoscope Generator & Drawing Tool
Cooking & Kitchen Tools
(30 tools)- Air Fryer Calculator
- Baker's Percentage Calculator for Bread, Pizza & Sourdough Hydration
- BBQ Meat Calculator
- Brine Calculator
- Cake Pan Converter for Batter and Bake Time
- Chocolate Tempering Calculator
Agriculture & Gardening Tools
(36 tools)- Compost C
- Corn Yield Calculator
- Crop & Combine Harvest Loss Calculator
- Crop Break-Even Price & Yield Calculator
- Crop Water Requirement Calculator
- Farm Pond Volume Calculator
Environment & Sustainability
(51 tools)- AQI to PM2.5 Converter
- Carbon Footprint Calculator
- Carbon Offset Calculator
- Commute Carbon Footprint Calculator
- Composting Carbon Footprint Calculator
- Dryer Cost and Line-Drying Savings Calculator
Logistics & Supply Chain Tools
(24 tools)- Box Packing Calculator
- Days Inventory Outstanding
- EOQ Calculator
- Fill Rate Calculator
- Travel Packing List Generator
- Freight Carbon Emissions Calculator by Shipping Mode
Marine & Boating Calculators
(33 tools)- Anchor Scope Calculator
- Antifouling Bottom Paint Calculator
- Apparent Wind Calculator
- Bilge Pump Capacity Calculator
- Boat Battery Bank and Runtime Calculator
- Boat Displacement and Load Capacity Calculator
Infrastructure & Systems Tools
(57 tools)- A/B Redundant Power and Failover Capacity Calculator
- Backup WAN Link Sizing Calculator
- Backup Window Calculator for Backup Duration, Throughput, and Storage
- Bandwidth Calculator for File Transfer Time and Required Speed
- Battery Runtime Calculator
- BGP Prefix Aggregation Calculator
Browser Games
(15 tools)- Emoji Catcher
- Fraction Pizza
- 1 Minute Typing Test
- Mental Math Trainer
- Memory Match Game
- Word Search Maker & Generator
Fun Calculators
(23 tools)- Age on Other Planets Calculator
- Caffeine Half-Life Calculator
- Cell Turnover Calculator
- Dog Years to Human Years Calculator
- Email Carbon Footprint Calculator
- File Size to Printed Pages Calculator