Interactive pricing calculator
Price a contract step by step and see every formula at work. Change any input on the left and each step, figure and chart recalculates with the same formulas the pricing engine uses. Values in teal in the formulas are BlockFinaX decisions; the walkthrough explains each one.
What the protection pays
Start with the outcome: what the buyer gets back for each possible rate at expiry.
Today's rate
Everything is measured from today's rate: it is the starting point for the price and for the payout. The engine reads it from the protocol's market data feed.
The payout rule
Nothing is paid unless the rate ends above the strike 11.60. Above it, each step pays a fixed amount until the limit 12.50. Drag the slider to try a rate at expiry.
How likely each outcome is
The engine estimates how the rate could move before expiry. Four things decide that.
Time to expiry
The longer the contract runs, the further the rate can wander. Time is counted to the second from the quote until the end time, so a short contract bought earlier in the day costs slightly more.
Expected drift
Some currencies weaken steadily against the dollar. The expected drift moves the centre of the likely outcomes.
Volatility
How much the rate swings, the input that moves the price most. The engine starts from recent swings, adds a margin for the market type, holds a minimum, and blends toward the long-run level over the contract.
Jump risk
Frontier currencies sometimes jump in a single day. Everyday volatility misses this, so the engine adds a chance of jumps.
The likely rates at expiry
Steps 3 to 6 together give the spread of possible rates at expiry. Laid over the payout rule, the shaded part is where the contract pays.
These chances come from the pricing model, not a forecast. Handbook chapters 1 and 2.
The fair price
The fair price is the average payout across the likely rates, in today's money.
Option values
The currency option formula does that averaging exactly: it values an option at the strike and one at the limit, for each possible number of jumps, and the contract is worth the difference.
Fair premium and checks
The spread value becomes a premium in USDC and a fair rate, and the quote is checked before it is signed.
What the buyer pays and receives
The contract applies the pool's terms to the signed fair rate, and later pays from the oracles' agreed rate.
Premium
The pool's underwriters sell at a multiple of the fair rate, their markup; the protocol adds a purchase fee.
Settlement
After the end time the oracles report the rate; the contract settles once enough of them agree within 1%, and the buyer claims the payout less the payout fee. Try a rate:
Example inputs, not live rates. The full method, every decision and the references are in the walkthrough and the formula handbook.