Your new basis starts here.
Getting started
NYBASIS is a free tool for modeling trade scenarios in stocks, options, crypto and prediction markets. See what adding, trimming or opening a position does to your cost basis, break-even and P&L before you place the order.
1Enter your position
Pick an asset, then fill in price, size and average cost. An example is loaded so you can look around; Reset clears it. No position yet? Check New position.
2Compare scenarios
Scenarios puts different sizes side by side. Tap a column to pick it, and the chart, matrix and Trade Ticket follow.
3Check your risk
Add a target and stop to see your P&L at each. Add your portfolio value and Position Sizing shows how much you can add before the position passes your limit.
4Share it
Post the Trade Ticket to X, copy the text or save an image. Your stop is never shown, and your size only if you choose Full size.
Your numbers stay in your browser. Tap ? on any card for definitions.
Position
You’re looking at an example. Edit any field, or tap Reset to start with your own position.
Scenarios
Enter your position above, or tap Example.
P&L Chart
Your P&L chart will show here.
P&L Matrix
Your P&L at each price will show here.
Assumes you add at your add price, then the stock moves to each price shown. Estimates ignore taxes, fees and dividends. Not financial advice.
Scenarios
Strategy Analysis
Estimates from the Black-Scholes model using the volatility, days and rate in Position, with volatility held steady. Ignores early exercise, dividends and fees. Real prices will differ.
P&L Matrix
Position Sizing
Trade Ticket
Prices only leaves out share counts and dollar totals, so you can post without showing your position size.
How it works
The math
- Add price is today’s price unless you enter one in Your plan.
- Trims keep your average cost; the realized gain or loss moves your break-even.
- Shorts: the same math with the sign flipped, so you profit when the price falls.
- Crypto leverage: liquidation assumes margin equals position cost ÷ leverage, less a 0.5% maintenance margin.
- Options: priced with Black-Scholes from the days and rate you enter, and the volatility you enter or the one implied by the option price.
- Prediction markets: a contract pays $1 if your side wins and $0 if not.
- Not included: taxes, fees, dividends, early exercise.
Who built it
Built by a full-time trader who asked Claude about averaging down one too many times. Questions or bugs: @NYBASIS on X.
Privacy
Your numbers stay in your browser. Nothing you enter is sent to or stored on a server.