Narasimha Makireddi

Software Developer · Creator of calculox.in

About

I'm a software developer who built calculox.in to give every Indian free access to accurate financial calculation tools. I found that most online calculators either lacked Indian-specific tax rules, had poor mobile experience, or were buried under ads — so I built all 14 from scratch.

Every formula on this site is sourced directly from official government publications — the Finance Act, RBI circulars, and GST Council notifications. The code is open on GitHub if you want to verify the implementation.

Tools, not financial advice

I am not a Chartered Accountant, SEBI-registered Investment Advisor, or CFP. calculox provides calculation tools for educational and planning purposes only — not personalised financial advice. For decisions specific to your situation, please consult a qualified CA or SEBI-registered advisor.

Formula Sources

Every calculator's formula is traced to a primary official source. This is what "verified formulas" means on this site:

Reserve Bank of India (RBI)

EMI formula, FD compounding methodology, RD calculations, and lending rate guidelines.

Finance Act 2025-26

Income tax slabs, rebate under Section 87A, deductions (80C, 80D, 80CCD), and surcharge rates.

GST Council Notifications

GST rates (0%, 5%, 12%, 18%, 28%), CGST/SGST/IGST split, and HSN-based rate categories.

SEBI Mutual Fund Regulations

SIP and CAGR calculation methodology for mutual fund return projections.

WHO BMI Classification

Body Mass Index ranges and health categories per the World Health Organization guidelines (2000).

What I built

  • EMI Calculator
  • SIP Calculator
  • FD Calculator
  • RD Calculator
  • Income Tax Calculator
  • GST Calculator
  • BMI Calculator
  • Percentage Calculator
  • CAGR Calculator
  • Simple Interest Calculator
  • Retirement Calculator
  • Home Loan vs Rent Calculator
  • Profit Margin Calculator
  • Scientific Calculator