REST API
JSON endpoints for every calculator. Send inputs, get structured outputs your code can act on.
The Ultimate Calculator Library
528 verified tools for finance, health, math, science, and 80+ more domains. Open in your browser, call the API, or plug into your AI agent through MCP.
-
187K+MCP tool calls completed
-
12.4M+Calculations served
-
<150msAverage response latency
Plays well with your AI stack
-
Claude
-
Anthropic
-
Cursor
-
Cline
-
Windsurf
-
Zed
-
GitHub Copilot
-
Ollama
-
OpenRouter
-
n8n
-
Mistral AI
Most popular calculators
Used by thousands of people every day
- 100 Day Calculator
- 12-Hour to 24-Hour Time Converter
- 10/1 ARM Calculator
- 1031 Exchange Tax Deferral Calculator (US)
- 1RM Calculator
- A-a Gradient Calculator
- 28/36 Rule Calculator
- 3x Rent Calculator
- 15 Percent Tip Calculator
- 16:10 Aspect Ratio Calculator
- 2D Distance Calculator
- 30 60 90 Triangle Calculator
Browse all categories
-
Financial
-
Health and Fitness
-
Math and Statistics
-
Time and Date
-
Geometry
-
Industry-Specific
-
Personal Finance
-
Physics and Engineering
-
Educational
-
Digital Life
-
Business and Marketing
-
Sports and Fitness
-
Weather and Climate
-
Chemistry
-
Wellness and Mindfulness
-
Smart Home and IoT
-
Futuristic and Emerging Tech
-
Banking Services
-
Miscellaneous
-
Adventure and Travel
-
Hobby and Craft
-
Pet Care
-
Career and Professional Development
-
Utilities
Built for AI agents and developers
Every calculator is API-first. MCP integration is on the way.
-
MCP server
Expose any calculator to Claude, Cursor, and other LLMs via Model Context Protocol — no glue code.
-
-
Embeddable widget
One script tag drops any calculator into your site or app, with locale-aware formatting included.
Recently added
Fresh tools published this month
-
Property Depreciation CalculatorEstimate annual real estate depreciation using the US MACRS straight-line method for residential (27.5 yr) and commercial (39 yr) property.
-
Dog Age in Human Years CalculatorConvert your dog's age into human years using the science-based logarithmic formula (16·ln(age)+31), with a linear puppy approximation under 1 year.
-
Brick Wall CalculatorCalculate how many bricks you need for a wall. Enter wall dimensions, brick size, mortar joint and waste to estimate total bricks required.
-
Future Value Calculator with ContributionsCalculate the future value of an investment with an initial principal plus regular monthly, quarterly or annual contributions and compound interest.
-
Shingle Bundle CalculatorEstimate how many shingle bundles you need for your roof. Enter roof dimensions, planes, waste allowance, and bundles per square to get a quick count.
-
Triangle Area Calculator Without HeightFind the area of a triangle without knowing its height. Enter the three side lengths and this Heron formula calculator returns the exact area.
-
Air Flow Rate Calculator From Pressure and DiameterCalculate air flow rate from pressure difference and pipe diameter. Get volumetric flow in m³/s, m³/h and CFM plus velocity using Bernoulli equation.
-
3D Line Equation From Two Points CalculatorFind the parametric and symmetric equation of a line in 3D from two points. Get the direction vector, components, and distance instantly.
01234567890123456789,012345678901234567890123456789,012345678901234567890123456789
Calculations served — and counting every second.
Frequently asked questions
How accurate are these calculators?
Each calculator is built from peer-reviewed formulas and tested against published reference values. We list our sources on each calculator's documentation page.
Can I use them on my website or app?
Personal use is always free. For embedding or commercial use, see our Terms or contact us for an integration plan.
Why are some pages in another language?
We translate calculators into 12 languages based on user demand. If you'd like a calculator in your language, send us a request.
Are my inputs saved or shared?
No. All calculations happen locally in your browser — we don't log, store, or share what you enter.
Can I use these in my AI agent or LLM workflow?
Yes — calculators are designed API-first. MCP server support is on the roadmap; once shipped, you'll be able to plug any calculator directly into Claude, Cursor, or other MCP-aware clients.