The 3-Source Formula Verification Rule
The web is crowded with calculators that generate contradictory results due to rounding errors, outdated tax laws, or copy-pasted formulas. At Calculatorji, every engine is developed under a strict engineering protocol.
1. The 3-Source Verification Rule
Before any calculator code is deployed to production, its underlying mathematical formula must be verified against at least three independent, authoritative sources:
Official statutory notifications or master circulars issued by primary regulators (RBI, CBDT, SEBI, EPFO, Ministry of Labour, NIH, WHO).
Peer-reviewed academic textbooks, standards (NCERT, BOMA, ISO 8601), or financial mathematics literature.
Real-world bank statement amortization schedules, certified auditor workbooks, or benchmark spreadsheet audits.
2. Pure TypeScript Calculation Engines
All calculation logic is decoupled from user interface components. Our engines (`_engine.ts`) are pure mathematical functions without external side-effects, allowing comprehensive automated test suites (`_engine.test.ts`) that assert exact outputs against stored fixtures before every build.
- Zero Floating-Point Artifacts: Currency calculations use rounded precision to avoid JavaScript binary floating-point rounding quirks (e.g. 0.1 + 0.2 = 0.30000000000000004).
- Leap Year Integrity: Date and age engines adhere to astronomical Gregorian calendar rules, handling leap days (February 29) without month-boundary leakage.
- Documented Rounding Rules: Every page explicitly documents whether statutory rounding is rounded half-up, truncated, or rounded to nearest whole rupee.
3. Named Human Expert Reviewers (YMYL)
Topics involving direct taxation, legal gratuity, and medical metrics are designated as Your Money or Your Life (YMYL). These tools carry the verified name, credential, and last-reviewed date of a qualified professional:
4. 48-Hour Error Rectification SLA
If any user or researcher identifies a discrepancy between our calculation output and an official bank statement or tax assessment, our engineering and editorial team commits to investigating and resolving the issue within 48 hours, followed by a transparent log entry in our public Formula Changelog.