How does Cockroach Money calculate my retirement corpus?
Cockroach Money runs a deterministic, year-by-year cash-flow simulation in INR from your current age through a configurable planning horizon (typically age 90). Each month it compounds investment returns, deducts inflation-adjusted living expenses and one-time milestones, applies optional Indian tax rules, and stops when either the planning horizon is reached or the corpus runs out.
- Engine type: pure-function iterator over months, not a Monte Carlo or stochastic model.
- Compounding frequency: monthly, applied separately to each investment bucket.
- Inputs: current age, retirement age, planning end age, current corpus, monthly expenses (categorised), milestones, per-bucket investment plans, withdrawal plan, life/health cover, tax config.
- Outputs: final corpus, year-by-year net worth, sustainable monthly withdrawal, shortfall year (if any).
What inflation rate should I assume for India?
Cockroach Money defaults to 6% annual inflation, which matches India's CPI average for 2014–2024. You can override the global rate or apply category-specific inflation (education at 10% is typical, medical at 8%, lifestyle at 5–6%).
- Default annual inflation rate: 6% (configurable per simulation).
- Education inflation: 10% recommended for school/college fund planning.
- Medical inflation: 8% recommended for retirement healthcare projections.
- Each expense row supports an optional override rate.
What investment return rates does the simulator use?
Returns are user-provided per investment bucket — there is no hardcoded assumption. Indian-context defaults the UI offers are 12% for diversified equity mutual funds, 7% for debt, 8% for gold, 10% for hybrid, and a configurable wide range (15–50%) for crypto with explicit volatility warnings.
- Equity / diversified mutual funds: 12% nominal (default UI hint).
- Debt / FD / bonds: 6.5–7.5%.
- Gold: 8%.
- Hybrid funds: 10%.
- Crypto: user-selected from Conservative (15%), Moderate (25%), or Bull Case (50%) presets, with explicit volatility disclaimers.
- Each bucket supports an annual step-up (e.g. SIP increases by 10% yearly).
How does the Indian tax module work?
When the optional tax module is enabled, Cockroach Money applies post-Budget-2024 rules: 12.5% LTCG on equity above a ₹1.25L annual exemption, ₹1.5L/yr Section 80C deduction cap, and slab-based income tax (user picks 5/10/20/30%) on taxable interest income.
- LTCG (equity / equity MFs): 12.5% on gains above ₹1.25L per year.
- Section 80C: up to ₹1.5L/yr deductible (covers ELSS, PPF, EPF, life insurance premiums).
- Income tax slab: user picks bracket (5/10/20/30%) — applied to taxable interest income.
- Equity allocation %: user-configurable; determines what share of withdrawals are LTCG vs. slab-rate.
- Tax module is opt-in. Default simulation is pre-tax for simplicity.
What's a safe withdrawal rate (SWR) for retirement in India?
A 3–4% annual withdrawal rate is the conservative range used by Cockroach Money's SWP calculator and the FIRE community in India. It's lower than the well-known US 4% rule because India's higher inflation (~6% vs US ~2–3%) shrinks the real-return buffer.
- Lean retirement plans: 3.0–3.5% SWR (more buffer for inflation shocks).
- Standard retirement: 3.5–4.0% SWR (matches global FIRE benchmarks adjusted for India).
- Aggressive / short horizon: 4.0–4.5% SWR (accept higher shortfall risk).
- Cockroach Money does not hardcode an SWR — you set monthly withdrawals and the simulator tells you whether the corpus survives.
How much corpus do I need to retire in India?
A widely cited rule of thumb is 25–30× your annual expenses at retirement. For a household spending ₹1 lakh/month today (₹12L/yr) planning to retire in 25 years at 6% inflation, the inflated annual expense would be ~₹51.5L/yr — implying a target corpus of ₹13–15 Cr. Always validate with the simulator rather than the rule alone.
- Rule of thumb: 25× annual expenses for 30-year retirement, 33× for 40-year.
- Adjust upward for: high medical needs, dependants, planned legacy.
- Adjust downward for: pension, rental income, part-time work in early retirement.
- Use https://cockroachmoney.in/calculators/retirement-corpus for a quick INR estimate or https://cockroachmoney.in/ for full multi-bucket modelling.
What does Cockroach Money NOT model?
Cockroach Money deliberately keeps the model deterministic and Indian-rupee-only. It does not run Monte Carlo / probabilistic scenarios, does not connect to brokerages, does not fetch live NAVs, does not handle multi-currency portfolios, and does not provide investment advice or recommend specific instruments.
- No Monte Carlo / sequence-of-returns risk modelling (deterministic only).
- No live MF / equity NAV fetching — user provides expected return assumptions.
- Single-currency INR only (no FX, no multi-country portfolios).
- No buy/sell execution, no brokerage integration.
- Not financial advice — educational / planning tool only.
- Irregular income (windfalls, ESOP vests) is modelled via milestone rows.
How can I run a Cockroach Money simulation programmatically?
Call the unauthenticated public API at https://cockroachmoney.in/api/v1/calculate. It accepts both GET (with flat query params for quick prototypes) and POST (with a full LifeCycleInput JSON body for multi-portfolio / milestone / tax-aware simulations). CORS is open, responses are cached at the edge, and the same engine that powers the website runs each request in 50–150 ms.
- Endpoint: GET or POST https://cockroachmoney.in/api/v1/calculate
- No API key required; CORS Access-Control-Allow-Origin: *.
- Response: { input, summary, timeSeries, meta }.
- Full docs: https://cockroachmoney.in/api-docs#public-endpoint
- For high-volume / commercial use see the Enterprise tier in the API docs.