Custom Calculator

The custom position is a blank canvas: start from a single leg and add calls, puts and shares in any combination the calculator can price. Every strategy in the menu is just a preset of this page, so anything that does not fit a named shape, from a ratio spread with three strikes to a position being rolled across expiries, is built here.

When it is used

Use it to model a position you already hold by typing each leg's strike, expiry and price from your broker's statement, to try a variation of a standard strategy, or to combine two strategies on the same stock. Legs can be added, duplicated and reordered, and a stock leg can be included so that hedges on an existing holding are priced together with it.

How it makes and loses money

The grid is the answer. Each cell values every leg with the model and sums them, so the shape of the position across prices and dates appears as soon as the legs are entered. The summary reports the entry cost, the maximum risk and return at the nearest expiry, breakevens and the probability of profit for whatever combination is on the page.

What to check in the grid

Watch the summary while adding legs: an unbounded max risk means a short option is uncovered, and an in-window note means the worst case arrives before expiry. The IV change slider shows how sensitive the whole position is to volatility.