Is my position data sent to a server?

No. Every calculation runs in your browser using the same pricing engine that generates the diagrams on the strategy pages. Nothing you enter is transmitted, logged or stored anywhere.

How accurate is the margin estimator?

It is a rough approximation, not SPAN. Real margin is computed by the exchange's SPAN engine, is recomputed intraday, expands as a position moves against you, and differs by broker. Use your broker's margin calculator before committing capital.

Can I model a calendar spread?

Yes. Give each option leg its own days-to-expiry. The payoff is drawn at the near leg's expiry, with any longer-dated leg valued by Black-Scholes at its remaining life — which is what produces a calendar's tent shape.

What is the break-even win rate shown next to reward-to-risk?

The share of outcomes that must land at maximum profit for the position to be flat overall, given its maximum loss. It ignores partial outcomes and all costs, so treat it as a floor, not a target.

Strategy calculators

One position, nine lenses. Build any multi-leg structure and read its payoff, breakevens, reward-to-risk, Greeks, volatility sensitivity, time decay, margin and size — all computed in your browser by the same engine that drew every diagram on this site.

How this works: there is one position, defined by the legs below. Every tab is a different view of it. Each option leg's implied volatility is solved from the premium you type, at that leg's own days-to-expiry — so the Greeks, the decay curve and the payoff line always describe the same position and cannot drift apart. Nothing you enter leaves your browser.

The position

Start from a documented strategy, or build your own. Give each option leg its own days-to-expiry to model a calendar or diagonal.

Load a strategy Underlying Spot price Lot size

ActionTypeStrike / entryPremiumQtyDays to expiry

Premium and days-to-expiry apply to option legs only. For a Future or Underlying leg, put your entry price in the strike column. Quantities above 1 create ratio spreads — which is what turns a defined-risk backspread into an undefined-risk ratio spread, and vice versa.

The calculators need JavaScript. Every strategy page carries a pre-rendered payoff diagram, Greek panels, decay curve and volatility curve as static SVG, so you lose nothing by browsing the A–Z index instead.

Profit & loss at expiry

The solid line is the payoff at expiry (at the near leg's expiry, if your legs differ). The dashed line is the position's theoretical value today, before time decay has run. Shaded green is profit, red is loss; the gold dots mark breakevens.

Rupee figures are per lot. "Unlimited" means no structural cap exists — a statement about the mathematics, not about likelihood. All figures exclude brokerage, STT, exchange charges, stamp duty and GST, which on a four-leg structure are paid eight times round trip.

Breakeven

Every underlying price at which the position's expiry payoff crosses zero, and how far each sits from spot.

Risk and reward

The reward-to-risk ratio compares the two structural extremes. The break-even win rate is what that ratio demands of you before costs — an iron condor risking more than it can make must win more often than it loses simply to stand still.

A reward-to-risk ratio is not an edge. It says nothing about how often each outcome occurs. A structure that makes ₹89 and risks ₹111 is not "bad", and one that makes ₹330 and risks ₹70 is not "good" — the market prices the probabilities, which is exactly why the ratios look the way they do. Read Risk of Ruin.

Days to expiry for the Greek readout

Theta is per calendar day. Vega is per one percentage point of implied volatility. Rho is per one percentage point of interest rate, and is a rounding error on weekly options.

Net Greeks across underlying prices

Each panel shows the whole position's net Greek, not one leg's. Signs are not constant — watch delta cross zero as the underlying travels across the strikes of a butterfly.

Gamma and theta always fight

Look at their signs. On almost every position they are opposite, and that is structural rather than coincidental: theta is the compensation you are paid for carrying gamma. There is no region of the surface where you collect one without the other.

Volatility impact simulator

Hold the underlying still, hold the clock still, and move implied volatility alone. This isolates vega from delta — which is precisely what happens to a long straddle the morning after a result is announced.

Implied volatility, as a share of entry IV

100% of entry IV

Sensitivity to implied volatility

Time decay simulator

Hold the underlying at spot and let only time pass. An upward slope means time is working for the position; downward means against it. Watch how the last week behaves compared with the first three.

Days remaining to expiry

at expiry

Value of the position as expiry approaches

Margin estimator

For a defined-risk structure the estimate is the structural maximum loss, which is close to what brokers charge once spread benefit is applied. For anything with a naked short leg it applies a percentage of notional plus the premium, per leg.

Initial margin, % of notional (naked legs)

This is an approximation, not SPAN. Real margin is computed by the exchange's SPAN engine from a scenario grid, is recomputed intraday, expands as the position moves against you, and differs between brokers. A short-option position that is fully margined at entry can be squared off by your broker after a move, at the worst possible price. Never size a position from this number — use your broker's margin calculator, then read Position Sizing.

Position size calculator

Fixed-fractional sizing: risk a constant share of equity per trade. Size against the structure's maximum loss where one exists, or against your own stop distance where it does not.

Account size (₹) Risk per trade (%) Size against

If it says zero lots, that is the answer

One NIFTY futures lot at 24,000 carries ₹18,00,000 of notional exposure. On a ₹5,00,000 account with a 1% risk budget of ₹5,000 and an 80-point stop, one lot risks 80 × 75 = ₹6,000 — already over budget before the market opens. A defined-risk option structure is often the only way a small account can size correctly at all.

A stop-loss is an instruction, not a structure. Indian indices gap on overnight news, and a stop does not execute at your price across a gap. Sizing against a stop assumes an exit the market is not obliged to give you. Sizing against a defined-risk structure's maximum loss does not.

Strategy comparison tool

Two documented strategies, side by side, with figures computed from the same arbitrage-consistent NIFTY chain. Neither is ranked above the other.

First strategy Second strategy

What the model assumes, and where it is wrong

The expiry payoff needs no model: it is the sum of each leg's intrinsic value minus what was paid, exactly piecewise-linear with kinks at the strikes. Everything else on this page — the dashed "today" line, the Greek panels, the decay curve, the volatility curve — comes from Black–Scholes–Merton for a European option at a 6.5% risk-free rate with no dividend yield, with each leg's implied volatility solved from the premium you entered.

Black–Scholes assumes constant volatility, continuous hedging, no jumps and European exercise. Indian index options are European and cash-settled, so exercise style is fine. The other three assumptions all fail. Volatility has a smile and a term structure; the market gaps; nobody hedges continuously. The consequence is that these curves are directionally right and quantitatively approximate — they understate the danger of short-gamma positions near expiry, and they ignore volatility skew entirely. Stock options in India are American-style and physically settled, which this model does not capture at all. Read the full Methodology.