Notes

Notes

Explainers that add something the calculator page does not already say: GST 2.0 slabs, old vs new regime, CTC vs Form 16, how to read an IFSC, and what “runs in the browser” actually means. Each one links back to a tool. Stub notes are kept off this list until they are written properly.

GST & invoices

• What 5%, 18%, and 40% actually sit on after GST 2.0

  How the 56th Council rationalisation changed everyday GST math, and why legacy 12/28 still haunt debit notes.

• CGST + SGST or IGST: what one invoice actually prints

  Place of supply is a legal test, not warehouse city. Same 18% can split half-and-half or sit entirely in IGST.

Tax & salary

• Old vs new tax regime: work a CTC without an email wall

  Side-by-side FY 2026–27 thinking for salaried India, linked to the local salary calculator.

• Standard deduction ₹75,000 and rebate 87A, without the slide deck

  FY 2026–27 new regime: ₹75,000 SD, 87A up to ₹12 lakh taxable, ₹60,000 cap. Useful, approximate, not CA advice.

• CTC vs in-hand vs Form 16

  Three numbers recruiters blur, and how to argue with an offer letter.

Banking & IDs

• How to read an IFSC before you hit send

  Bank code, zero, branch, and why a valid IFSC with the wrong account still loses money.

• Aadhaar checksum is not KYC. Stop pasting twelve digits into random sites

  A check-digit pass means the digits agree with each other. UIDAI issues numbers. Phishing, VID, and when a local typo check is enough.

Investing

• SIP vs lump sum when inflation is not zero

  Rupee cost averaging is how humans keep investing. Lump sum often wins on a rising chart. Toggle inflation so the corpus is not a poster.

Privacy & how we build

• What “runs in the browser” does and does not mean

  Calculator math can be local while ads and analytics still use the network.

• JWT in your tab vs jwt.io

  Same base64url algebra. jwt.io is a third-party origin with scripts you do not audit. Slack screenshots are a dump with better lighting.