Our Three Principles of Calculation
Official Sourcing
We never rely on third-party blogs or secondary interpretations. All tax slabs, interest compounding rules, and statutory limits originate from official government publications.
Zero-Data Leakage
100% of calculations execute locally in your web browser. No financial figures, salaries, or health inputs are ever transmitted to our servers or saved in remote databases.
Continuous Verification
Automated test suites with over 200 verification vectors run before any code release to guarantee zero regression against verified benchmark values.
Standard Mathematical & Financial Models
The exact formulas implemented in our core engines, aligned with Indian banking and financial regulations:
Equated Monthly Installment (EMI)
Monthly Reducing Balance CompoundingApplied in: EMI, Home Loan, Car Loan, Personal Loan Calculators
Variables & Constants
EEquated Monthly InstallmentPPrincipal loan amount borrowedrMonthly interest rate: (Annual Interest Rate / 12) / 100nTotal number of monthly installments (Tenure in years × 12)
Interest is calculated on the remaining balance after deducting each month's principal repayment component. Processing fees and prepayment penalties, when provided, are adjusted to demonstrate effective APR.
Systematic Investment Plan (SIP)
Future Value of an Annuity Due with Monthly CompoundingApplied in: SIP Calculator, Mutual Fund Return Estimator
Variables & Constants
MEstimated maturity amountPMonthly contribution installmentiPeriodic monthly return: (Expected Annual Rate / 12) / 100nTotal number of monthly contributions (Years × 12)
Returns are calculated assuming compounding at every monthly investment cycle. Results are illustrative estimates based on user-supplied expected rates and do not guarantee market returns.
Fixed Deposit (FD) Maturity
Quarterly Compounded Interest (Indian Commercial Banking Standard)Applied in: FD Calculator, Fixed Deposit Returns
Variables & Constants
ATotal maturity valuePPrincipal deposit amountrAnnual interest rate (%)tTenure in years
Indian banks compound fixed deposit interest on a quarterly basis. CalcBit implements the standard RBI quarterly compounding model for all tenures exceeding 180 days.
Income Tax Calculation (FY 2026-27 & FY 2025-26)
Progressive Slab System with Statutory Rebates & CessApplied in: Income Tax Calculator, Old vs New Regime Comparison
Variables & Constants
Taxable IncomeGross Income - Standard Deduction (₹75k New / ₹50k Old) - Chapter VI-A DeductionsRebate u/s 87AZero tax liability if taxable income is within statutory threshold (up to ₹7 Lakh in New Regime)Cess4% levied on total income tax payable after applying rebates and surcharges
Updated for Finance Act 2025/2026 revisions. Supports comparisons across New Tax Regime (default u/s 115BAC) and Old Tax Regime with Sections 80C, 80D, 24(b) home loan interest, and HRA exemptions.
Goods and Services Tax (GST)
Additive / Back-Calculated Statutory Percentage BreakdownApplied in: GST Calculator (Inclusive, Exclusive & Reverse GST)
Variables & Constants
BasePre-tax net price of goods or servicesRApplicable GST rate (5%, 12%, 18%, or 28%)CGST / SGSTEqual split of 50% each for intra-state transactionsIGSTFull 100% GST for inter-state transactions
Accurately breaks down central and state components to eliminate rounding errors in invoicing calculations.
Salary & CTC Breakdown
Statutory Payroll Deduction ModelApplied in: Salary Calculator, CTC to In-Hand Take Home
Variables & Constants
Gross SalaryCTC - Employer PF (12% of basic up to limit) - Gratuity Provision (4.81%)Employee PF12% of Basic + DA, subject to statutory limitsProfessional TaxState-specific slabs (e.g. ₹200/month or state statutory limit)
Provides transparency on real monthly take-home salary after compulsory deductions, preventing unexpected pay-slip surprises.
Statutory & Regulatory Data Sources
We cite primary public sources. We do not use secondary blog posts or unverified aggregators:
| Domain | Primary Authority | Scope & Rules Cited | Review Cadence |
|---|---|---|---|
| Income Tax | Income Tax Department, Ministry of Finance, Government of India | Income Tax Act 1961, Annual Finance Acts, official tax slabs (Old & New Regimes), standard deduction, and Section 87A rebate rules. | Every Union Budget & official CBDT notification |
| Banking & Loans (EMI) | Reserve Bank of India (RBI) | Master Direction on interest rates, reducing-balance compounding conventions, and banking lending standards. | Quarterly RBI MPC updates & policy guideline revisions |
| Indirect Tax (GST) | Central Board of Indirect Taxes and Customs (CBIC) & GST Council | Statutory GST slabs (0%, 5%, 12%, 18%, 28%), CGST/SGST intra-state distribution, and IGST inter-state application. | Every GST Council meeting & notification |
| Retirement & PF (EPF) | Employees' Provident Fund Organisation (EPFO) | Statutory EPF wage ceiling (₹15,000), 12% employee share, 3.67% EPF / 8.33% EPS employer split, and annual declared interest rate. | Annual interest declaration & statutory wage threshold updates |
| Small Savings (PPF, SSY, SCSS) | Department of Economic Affairs, Ministry of Finance | Quarterly sovereign small-savings scheme interest rate circulars, compounding rules, and lock-in periods. | Quarterly (March, June, September, December) |
| Investments & Securities | Securities and Exchange Board of India (SEBI) | Mutual fund categorisation, systematic investment disclosures, and investment risk illustration frameworks. | Bi-annual circular reviews |
| Health & Fitness | World Health Organization (WHO) & ICMR | Body Mass Index (BMI) cutoffs, Mifflin-St Jeor Basal Metabolic Rate equation, and ICMR nutritional benchmarks for Indian populations. | Annual review against international peer-reviewed medical standards |
Important Educational & Informational Notice
CalcBit provides simulation tools for financial estimation, educational guidance, and informational purposes. Calculations do not constitute licensed financial advice, tax filing endorsements, or clinical medical prescriptions. Actual interest rates, taxes, and bank terms vary based on personal credit scores, institutional policies, and statutory amendments. Consult a SEBI-registered investment adviser, Chartered Accountant (CA), or qualified medical professional for decisions specific to your situation.