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Methodology and sources

Kairocal estimates brokerage and statutory charges for Indian markets from a JSON rules engine. The goal is transparent math that is easy to audit against a real contract note. Use the brokerage calculator, compare brokers, or open the charges database.

What is included

  • Brokerage (flat, percent, or capped per leg)
  • STT (segment-specific buy/sell application)
  • Exchange transaction charges (NSE / BSE equity rates)
  • SEBI turnover fees
  • IPFT (₹10 per crore traded value)
  • Stamp duty (buy-side rates by segment)
  • DP charges with broker fee, depository fee, per-ISIN, and GST
  • GST at 18% on brokerage, exchange, SEBI, IPFT, and DP
  • Break-even sell price via binary search

Segments

Equity delivery, equity intraday, MTF, futures, options, commodity, and currency. F&O / commodity / currency use simplified public-rate approximations for exchange and STT. Always confirm with your broker and exchange circulars for live trading.

Broker rules dataset

Version 2026-04-01, effective 2026-04-01. Public schedule approximations for equity cash and simplified F&O/commodity/currency. Verify against current broker tariff sheets before relying for tax filing.

Rules live in src/data/broker-rules.json. Update that file to change schedules without touching engine code. Each broker has an effectiveFrom date for schedule versioning.

DP model

Delivery and MTF sells apply DP. Total DP = per-ISIN rate × ISIN count. Components (broker fee vs depository fee) are stored separately so the ledger can match contract-note style lines. GST on DP is shown as its own line.

Engine separation

All formulas live in src/lib/engine. UI and Zustand store only pass inputs and render results. Unit tests cover equity cash paths and non-negative charges across brokers.

Not included yet

  • Live PostgreSQL admin panel and write API for charge edits
  • Automated broker-site scraper for tariff updates
  • Immutable audit log service for production ops

Those need a backend store. The JSON rules file plus the Charges page act as the current charge database and revision surface.

Disclaimer

Kairocal is an estimation tool. It is not a SEBI-registered platform, tax advisor, or substitute for your broker contract note. Verify figures before trading or filing returns.