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ExpertToolkit
Calculators
Health calculators
  • BMI calculator
  • BMR calculator
  • Body fat calculator
  • Ideal weight calculator
Math calculators
  • Percentage calculator
  • Circle area calculator
  • Rectangle area calculator
  • Pythagorean theorem calculator
  • Tip calculator
  • Discount calculator
Converters
Unit conversions
  • Meters to Feet
  • Feet to Meters
  • Inches to Centimeters
  • Centimeters to Inches
  • Miles to Kilometers
  • Kilometers to Miles
  • Kilograms to Pounds
  • Pounds to Kilograms
  • Grams to Ounces
  • Celsius to Fahrenheit
  • Fahrenheit to Celsius
  • Liters to Gallons
  • Gallons to Liters
  • Kilometers/hour to miles/hour
  • Square meters to square feet
Nutrition conversions
  • Apple calories, 1 medium
  • Apple protein, 1 medium
  • Avocado calories, 1 medium
  • Avocado fat, 1 medium
  • Banana calories, 1 medium
  • Banana carbs, 1 medium
  • Beef with egg calories
  • Beef with egg protein
Nutrition comparisons
  • Almonds vs peanut butter
  • Avocado vs olive oil
  • Banana vs apple
  • Blueberries vs strawberries
  • Whole wheat bread vs oats
  • Broccoli vs spinach
  • Chicken breast vs lean beef
  • Raw vs cooked chicken breast
Material density
  • Concrete: 1 yd3 to tons
  • Concrete: 10 yd3 to tons
  • Gravel: 1 yd3 to tons
  • Dry sand: 1 yd3 to tons
  • Topsoil: 1 yd3 to tons
  • Asphalt: 10 tons to yd3
  • Diesel: 100 gal to lb
  • Diesel: 1 bbl to lb
  • Water at 20C: 1 gal to lb
  • Gasoline: 100 gal to lb
Wire gauge
  • 12 AWG, 20A, 50 ft
  • 10 AWG, 30A, 75 ft
  • 120V, 15A, 75 ft
  • 120V, 20A, 50 ft
  • 240V, 30A, 25 ft
  • 240V, 50A, 100 ft
  • 12 AWG vs 10 AWG
  • 10 AWG vs 8 AWG
  • Kitchen outlet, 20A
  • EV charger, 50A at 240V
Formulas
Health
  • BMI formula
Math
  • Percentage formula
  • Circle area formula
Finance
  • Compound Interest formula
  • Mortgage formula
Tables
Length tables
  • Meters to feet table
  • Inches to centimeters table
  • Miles to kilometers table
Weight tables
  • Kilograms to pounds table
Temperature tables
  • Celsius to Fahrenheit table

AI assistant connector

Use ExpertToolkit inside ChatGPT, Claude & Cursor

Call ExpertToolkit's calculators, unit converters, and USDA nutrition data directly from your AI assistant. It connects over the Model Context Protocol (MCP) — free, with no sign-up and no API key.

MCP endpoint

https://mcp.experttoolkit.net

What you can do

Nine tools, grouped by what they solve. Ask in plain language and your assistant picks the right one.

Unit conversion

  • convert_units

    Convert 10 meters to feet, or 2 cups of flour to grams.

  • search_units

    Find every unit that measures pressure or energy.

Calculators

  • calculate_mortgage

    Monthly payment on a $400k loan at 6.5% over 30 years.

  • calculate_loan_payment

    Amortized payment for any principal, rate, and term.

  • calculate_compound_interest

    Grow $10k at 7% compounded monthly for 20 years.

  • calculate_bmi

    Body Mass Index from height and weight, metric or imperial.

Nutrition (USDA data)

  • nutrition_lookup

    Macros and calories for raw chicken breast per 100 g.

  • nutrition_serving

    Protein and calories for a specific serving size.

  • nutrition_compare

    Compare chicken breast vs turkey breast side by side.

Set up your assistant

Every client uses the same endpoint with no authentication.

ChatGPT (Plus / Pro)

  1. Open Settings and enable Developer mode under Connectors (or Plugins).
  2. Choose Add connector / Add custom connector.
  3. Paste the MCP endpoint URL below and select No authentication.
  4. Save, then ask ChatGPT to convert a unit or run a calculation.
https://mcp.experttoolkit.net

Claude Desktop / Claude.ai

  1. Open Settings then Connectors.
  2. Choose Add custom connector.
  3. Paste the MCP endpoint URL below (no auth required) and save.
  4. Start a chat and ask Claude to use an ExpertToolkit tool.
https://mcp.experttoolkit.net

Cursor, Windsurf & other MCP clients

Add ExpertToolkit to your MCP configuration file (for example Cursor's mcp.json):

JSON
{
  "mcpServers": {
    "experttoolkit": {
      "url": "https://mcp.experttoolkit.net"
    }
  }
}

Also available

Public REST API

Prefer a plain HTTP call? Convert units with a simple GET request — no key required.

GET
https://www.experttoolkit.net/api/v1/convert?from=meter&to=foot&val=10

llms.txt

A machine-readable index of ExpertToolkit for AI crawlers and agents that follow the llms.txt convention.

View /llms.txt

Frequently asked questions

Is it free?
Yes. The ExpertToolkit MCP server and public REST API are free to use — no paywall, no usage tier, and no cost to connect it to your AI assistant.
Which AI assistants work?
Any client that supports the Model Context Protocol (MCP): ChatGPT (Plus and Pro with developer mode), Claude Desktop and Claude.ai custom connectors, Cursor, Windsurf, and other MCP-compatible tools.
Do I need to sign up?
No. There is no account, sign-up, or API key required. The MCP endpoint uses no authentication — you just add the URL to your assistant.
Are the numbers accurate?
Yes. Conversions map to NIST and BIPM standard definitions, calculators use published financial and health formulas, and nutrition data comes from the USDA dataset — the same engines that power the ExpertToolkit website.

Prefer to use the tools directly?

Every calculator and converter is also on the web — no setup needed.

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ExpertToolkit

Calculators, converters, and reference tools designed for clarity, reproducible results, and transparent methodology—built for students, professionals, and everyday use. Built with verified formulas, transparent methodology, and standards-based conversions.

BIPM/NIST Standards Reviewed
Method and AccuracyStandards: reviewed units and formulasMethodologyEditorially maintainedStandards reviewed regularly

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Approval Cohort

  • Chicken breast protein
  • Chicken vs turkey breast
  • Top protein foods
  • Concrete yd3 to tons
  • Steel m3 to kg
  • 12 AWG 20A check

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Release 2.5Market: United States