Small, fast, single-file calculators I built for my own trading — plot the payoff of any options or futures position before I take it.

Before entering an options position it helps to see the whole picture: max profit, max loss, breakevens and the shape of the payoff curve. These tools do exactly that for the contracts I trade.
Each instrument gets its own self-contained HTML file — stocks, crude, Gold Mini, Silver Mini and USDINR — with the correct lot sizes and strike steps baked in. They autosave locally and draw a live payoff curve.
For stocks, users can enter any symbol along with its lot size. Multiple stocks and their respective lot sizes can also be imported using a CSV file. The data is automatically saved locally, and the system calculates the corresponding Profit & Loss accordingly.
Note: this is a personal tool built for my own use and shared for educational purposes only. It is not investment advice, a recommendation, or a solicitation to trade. Markets carry risk; do your own research.