OC
OptionCraft
Learn by Building • 100% client-side
Manual + Delayed Data • Free Forever
Level 1What is an Option?

You pay a small deposit to reserve the right to buy a house later. That's a Call.

  • Call = right to BUY at strike, Put = right to SELL at strike
  • Premium = price you pay for that right
  • Strike = agreed price, Expiry = deadline
  • At expiry: Call worth max(0, Stock - Strike), Put worth max(0, Strike - Stock)
🎯 Try: Drag the stock price slider. See when your Call turns green (profit).

House Analogy

You see a house listed for $100k. You pay $3k to reserve the right to buy it at $100k within 30 days. If house goes to $120k, you profit $17k. If it stays at $90k, you let it expire and lose only $3k. That's a Call option. Put is the opposite — right to sell.

Educational only. Not financial advice. Runs 100% in your browser.
Market Inputs (manual)
P/L at ExpiryCurrent: $100
Net Cost / Credit
-3.00
P/L at $100
-3.00
Max Profit
$47.00
Max Loss
$-3.00
Breakevens
$103.00
Quick Templates

Strategy Legs (1)

Manual entry: paste premiums from Yahoo Finance delayed chain. No API needed.
Why this is different
  • No API key, no tracking, runs offline
  • Teaches with analogies before Greeks
  • 5 levels = beginner never sees Iron Condor on day 1
  • Manual entry = you learn premium, not just click chain