GetCalcly

AI Agent Tools

MCP Calculator Tools for AI Agents

Connect GetCalcly's free calculator API to Claude, Cursor, and any MCP-compatible AI agent. Get accurate mortgage, BMI, salary, and percentage results directly in your AI conversations — no signup, no API key, instant access.

What is Model Context Protocol?

Model Context Protocol (MCP) is an open standard that lets AI agents discover and use external tools. Instead of relying on training data or guessing, an agent can call a real calculator, database, or API to get precise, current results. MCP is supported by Claude, Cursor, and a growing ecosystem of AI tools and agent frameworks.

GetCalcly's MCP server exposes 31 production-ready calculator tools — the same math engine that powers the getcalcly.com website. Each tool accepts structured inputs (validated with Zod schemas) and returns formatted results with full breakdowns. This makes GetCalcly a practical, zero-friction addition to any AI agent workflow that needs reliable calculations.

Available MCP Tools

Thirty-one calculator tools — each with typed inputs, validated schemas, and detailed results.

calculate_macros

Macro Calculator

Estimate calories, protein, carbohydrates, fat, and fiber.

Inputs

  • body data
  • activity
  • goal

Use case: Nutrition planning

calculate_ideal_weight

Ideal Weight Calculator

Compare four formulas with a healthy BMI range.

Inputs

  • sex
  • height

Use case: Healthy-weight context

calculate_pace

Pace Calculator

Calculate running pace, speed, and race projections.

Inputs

  • distance
  • unit
  • time

Use case: Run and race planning

calculate_target_heart_rate

Target Heart Rate Calculator

Calculate five Karvonen training zones.

Inputs

  • age
  • resting heart rate

Use case: Workout intensity planning

calculate_pregnancy_due_date

Pregnancy Due Date Calculator

Estimate due date and trimester milestones from LMP, conception, or IVF.

Inputs

  • method
  • date
  • cycle length

Use case: Pregnancy calendar estimates

calculate_mortgage_payoff

Mortgage Payoff Calculator

Calculate extra-payment payoff time and interest savings.

Inputs

  • balance
  • rate
  • monthly payment
  • extra payment

Use case: Mortgage acceleration planning

calculate_refinance

Refinance Calculator

Compare payment, interest, closing costs, and break-even after refinancing.

Inputs

  • current loan
  • new rate
  • new term
  • closing costs

Use case: Refinance decisions

calculate_debt_payoff

Debt Payoff Calculator

Compare avalanche and snowball payoff strategies across debts.

Inputs

  • debt array
  • extra payment
  • strategy

Use case: Multi-debt payoff planning

calculate_take_home_pay

Take-Home Pay Calculator

Estimate net monthly and annual pay after simplified deductions.

Inputs

  • gross pay
  • tax rates
  • retirement
  • health premium

Use case: Paycheck and offer comparisons

calculate_rent_vs_buy

Rent vs. Buy Calculator

Compare home sale proceeds with renting and investing the difference.

Inputs

  • home
  • rent
  • rates
  • horizon

Use case: Housing decision scenarios

calculate_retirement

Retirement Calculator

Project savings, real purchasing power, required nest egg, and sustainable income.

Inputs

  • ages
  • current savings
  • monthly contribution
  • return
  • inflation
  • income target

Use case: Retirement readiness and scenario planning

calculate_house_affordability

House Affordability Calculator

Estimate a maximum home price using both housing and total-debt DTI constraints.

Inputs

  • income
  • monthly debts
  • down payment
  • rate
  • tax
  • insurance
  • HOA
  • DTI limits

Use case: Home-shopping budgets and lender conversations

calculate_credit_card_payoff

Credit Card Payoff Calculator

Calculate a payoff timeline, total interest, and negative-amortization warnings.

Inputs

  • balance
  • APR
  • monthly payment or target months
  • extra payment

Use case: Debt payoff plans and extra-payment comparisons

calculate_roi

ROI Calculator

Calculate net gain, ROI, annualized return, multiple, and break-even value.

Inputs

  • initial investment
  • final value
  • costs
  • income
  • holding period

Use case: Investment and business return comparisons

calculate_sales_tax

Sales Tax Calculator

Add tax, extract it from an inclusive total, or solve the effective rate.

Inputs

  • mode
  • amounts
  • tax rate

Use case: Shopping totals, invoices, and tax-inclusive pricing

calculate_budget

Budget Calculator

Summarize monthly cash flow, category shares, savings rate, and guideposts.

Inputs

  • net income
  • housing
  • utilities
  • transport
  • food
  • health
  • debt
  • savings
  • other

Use case: Personal cash-flow and savings planning

calculate_compound_interest

Compound Interest Calculator

Project growth with recurring contributions and a year-by-year schedule.

Inputs

  • principal
  • annualRate
  • years
  • contribution
  • contributionFrequency
  • compoundFrequency

Use case: Savings goals, investment projections, contribution planning

calculate_auto_loan

Auto Loan Calculator

Estimate vehicle financing with tax, fees, trade-in, down payment, and APR.

Inputs

  • vehiclePrice
  • downPayment
  • tradeInValue
  • salesTaxRate
  • fees
  • interestRate
  • termYears

Use case: Dealer offer comparisons and vehicle financing

calculate_body_fat

Body Fat Calculator

Estimate body fat, fat mass, and lean mass from circumference measurements.

Inputs

  • gender
  • weightLbs
  • heightInches
  • neckInches
  • waistInches
  • hipInches

Use case: Body-composition trend tracking

calculate_fraction

Fraction Calculator

Calculate, simplify, and explain operations on two fractions.

Inputs

  • numeratorA
  • denominatorA
  • numeratorB
  • denominatorB
  • operation

Use case: Exact arithmetic, homework checking, recipe scaling

calculate_date_range

Date Range Calculator

Count calendar days, weekdays, weekends, and weeks between dates.

Inputs

  • startDate
  • endDate
  • inclusive

Use case: Scheduling, booking durations, project timelines

calculate_statistics

Statistics Calculator

Calculate descriptive statistics for a numeric dataset.

Inputs

  • values (number array)

Use case: Data summaries, analysis, and result verification

calculate_loan

Loan Calculator

Calculate monthly loan payment with full amortization schedule. Works for auto, personal, and student loans.

Inputs

  • loanAmount (USD)
  • interestRate (%)
  • loanTermYears (1–30)

Use case: Auto loans, personal loans, student loans, installment loans

calculate_deferred_payment

Deferred Payment Calculator

Calculate lump sum due at maturity with compound interest. Configurable compounding frequency.

Inputs

  • principal (USD)
  • interestRate (%)
  • termYears
  • compoundFrequency (annually/semiannually/quarterly/monthly)

Use case: Balloon loans, deferred payment loans, compound interest planning

calculate_bond

Bond Calculator

Calculate zero-coupon bond purchase price, discount, and yield to maturity.

Inputs

  • faceValue (USD)
  • discountRate (%)
  • yearsToMaturity

Use case: Bond pricing, present value, zero-coupon bond valuation

calculate_mortgage

Mortgage Calculator

Full monthly payment breakdown with principal & interest, property tax, insurance, PMI, HOA, and year-by-year amortization schedule.

Inputs

  • homePrice (USD)
  • downPayment (USD)
  • interestRate (%)
  • loanTerm (years, 1–50)
  • propertyTax, insurance, HOA, PMI (fixed or %)

Use case: Home affordability, loan comparison, refinance planning

calculate_bmi

BMI Calculator

Body Mass Index from weight and height, with the corresponding weight category.

Inputs

  • weightPounds (lbs)
  • heightFeet
  • heightInches (0–11)

Use case: Health screening, fitness tracking, wellness planning

calculate_salary

Salary Calculator

Convert hourly wage to weekly, monthly, and annual salary.

Inputs

  • hourlyRate (USD)
  • hoursPerWeek (default 40)

Use case: Job offer comparison, freelance rate planning, budget estimates

calculate_percentage

Percentage Calculator

Calculate what percentage one value is of another.

Inputs

  • valueA (part)
  • valueB (total)

Use case: Discounts, test scores, growth rates, everyday math

calculate_age

Age Calculator

Calculate exact age from a birth date. Returns years, months, days, total weeks, next birthday, zodiac sign, and birth weekday.

Inputs

  • birthDate (YYYY-MM-DD)
  • targetDate (optional)

Use case: Age verification, birthday countdown, date math

calculate_calories

Calorie Calculator

Estimate daily calorie needs using Mifflin-St Jeor. Returns BMR, TDEE, and targets for weight loss, maintenance, and gain.

Inputs

  • age
  • gender (male/female)
  • weightLbs
  • heightFeet, heightInches
  • activityLevel (sedentary–veryActive)

Use case: Nutrition planning, weight management, fitness goals

How to Connect

Claude Code

Add this to your claude.json or settings.json MCP servers list:

{
  "mcpServers": {
    "getcalcly": {
      "type": "url",
      "url": "https://getcalcly.com/api/mcp"
    }
  }
}

Claude.ai

In Claude.ai (desktop or web):

  1. 1. Go to Settings → MCP Servers
  2. 2. Click Add Server
  3. 3. Enter URL: https://getcalcly.com/api/mcp
  4. 4. The calculator tools appear instantly

Frequently Asked Questions

What is MCP (Model Context Protocol)?

MCP is an open protocol that lets AI agents like Claude securely connect to external tools and data sources. Instead of the AI guessing a calculation or describing the formula, it can call a real calculator tool and return precise results. GetCalcly provides 31 tested calculator tools through its MCP server, including mortgage, retirement, affordability, debt payoff, health, date, and math tools.

How do I connect GetCalcly MCP tools to Claude?

In Claude Code, add getcalcly to your claude.json or settings.json MCP servers list with the URL https://getcalcly.com/api/mcp. In Claude.ai, go to Settings → MCP Servers → Add Server, enter the same URL, and the calculator tools will become available in your conversations. No API key or account is needed.

Is the MCP API free to use?

Yes. The GetCalcly MCP server is completely free — no signup, no API key, no rate limiting beyond basic fair-use thresholds. It runs the same calculation engine that powers the getcalcly.com website, so the results you get through an AI agent match what you would see on the site.

Do I need an API key or authentication?

No. The MCP endpoint at https://getcalcly.com/api/mcp is open and stateless. You can connect any MCP-compatible client directly without authentication. This makes it easy to add calculator tools to your agent workflows, prototypes, and personal projects.

Which AI agents and tools support MCP?

Claude Code, Claude.ai (desktop and web), Cursor, Continue, and a growing number of LLM clients and agent frameworks support MCP. Any client that implements the Model Context Protocol specification can connect to GetCalcly's MCP server and use the available calculator tools.

What data do you collect when I use the MCP API?

The MCP endpoint is stateless — we do not store calculation inputs, results, or session data. Basic request metadata (IP, timestamp) may be logged for operational monitoring, similar to website visits. See our Privacy Policy for full details.

Related calculators

Explore more fast calculators from GetCalcly.

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Percentage Calculator

Find what percent one value is of another.

Fraction Calculator

Calculate and simplify fractions with mixed-number, decimal, and step results.

Statistics Calculator

Find mean, median, mode, quartiles, variance, and standard deviation.