# TrueCalci

> TrueCalci is a precision, deterministic computational workstation engineered for global households, real estate investors, quantitative analysts, structural engineers, and autonomous AI agents.

## Core Calculators
- [Remote Contractor Take-Home Matrix](https://truecalci.com/#contractor_matrix): 1099 vs. W-2 tax parity, 15.3% Self-Employment Tax (SECA), 50% SE deduction, 20% Section 199A QBI deduction, corporate benefits valuation, and exact breakeven billing rate solver.
- [US Mortgage PITI](https://truecalci.com/#mortgage): Calculates monthly principal, interest, property taxes, home insurance, and automated Private Mortgage Insurance (PMI) with full amortization schedules.
- [European VAT & Sales Tax](https://truecalci.com/#vat): Instant Add and Remove VAT calculations across UK (20%), Germany (19%), France (20%), Spain (21%), Italy (22%), and global sales tax regions.
- [Tip & Restaurant Bill Splitter](https://truecalci.com/#tip): Itemized restaurant bill splitting with custom tip percentage allocations.
- [Compound Wealth & 401(k)](https://truecalci.com/#compound): Exponential future value compounding simulator for retirement, ETF Sparplan, and Roth IRA savings.
- [Black-Scholes Options Pricing](https://truecalci.com/#options): Closed-form European call and put option valuation with analytical Greeks (Delta, Gamma, Vega, Theta, Rho).
- [Euler-Bernoulli Beam Bending](https://truecalci.com/engineering-formulas.html): Center deflection, maximum bending moment, and extreme fiber stress for simply supported beams.
- [2D Ballistic Projectile Motion](https://truecalci.com/engineering-formulas.html): Total flight time, horizontal range, and apogee height under standard terrestrial gravity.
- [Ordinary Least Squares Linear Regression](https://truecalci.com/#regression): Bivariate linear model fitting with slope, intercept, Pearson r, and R-squared.
- [Indian Income Tax (Budget 2025-26)](https://truecalci.com/#tax): Statutory New Tax Regime slabs, standard deduction (₹75,000), Section 87A rebate, and HNI surcharges.
- [SIP & Step-Up Compounding](https://truecalci.com/#sip): Mutual fund systematic investment plan with annual step-up percentage and wealth gain ratio breakdown.

## Machine-Readable API & Protocols
- [OpenAPI 3.1 Catalog](https://truecalci.com/openapi.json): Machine-readable REST API schema for all calculation endpoints.
- [Model Context Protocol (MCP)](https://truecalci.com/.well-known/mcp.json): Standard MCP tool manifest for Claude Desktop, Cursor, and agent runtimes.
- [A2A Agent Card](https://truecalci.com/.well-known/agent-card.json): Agent-to-Agent discovery card per A2A protocol specification.
- [API Catalog](https://truecalci.com/.well-known/api-catalog): RFC 9727 linkset directory of services.
- [Agent Authentication](https://truecalci.com/auth.md): Registration guidelines, bearer tokens, and OAuth metadata discovery.
- [Unabridged Technical Handbook](https://truecalci.com/llms-full.txt): Complete mathematical formulas, LaTeX derivations, and unit bounds.