Same-Contract Premium Consistency

Currency Option Put-Call Parity Calculator

Compare entered European currency call-minus-put premiums with discounted spot-minus-strike put-call parity for the same pair, strike and expiry. The result is a mathematical consistency diagnostic, not an executable arbitrage claim.

Same strike and expiryTwo currency ratesNo arbitrage verdictModel 1.0.0

Enter one matched call-and-put case

The call and put must share the same European underlying orientation, strike, expiry, settlement assumptions and observation time. Enter both premiums as quote currency per one base unit.

Entered

Model boundary: The residual compares entered premiums with one continuously compounded discounted-parity identity. It does not observe synchronized executable quotes, bid-ask spreads, funding, collateral, taxes, credit, exercise eligibility or settlement.

Enter matched call and put premiumsThe result will compare entered call-minus-put premium with discounted spot-minus-strike parity and show two corresponding forward-rate diagnostics.

How currency-option put-call parity is checked

Reference = spot × e−base rate × T − strike × e−quote rate × TParity residual = entered call − entered put − referenceRate-parity forward = spot × e(quote rate − base rate) × TPremium-implied forward = strike + (entered call − entered put) × equote rate × T

European put-call parity links a call and put with the same underlying orientation, strike and expiry to discounted spot and strike cash flows. In the page convention, spot is quote currency per one base currency. The quote-currency rate discounts the strike payment, while the base-currency rate discounts the underlying base-currency leg.

The calculator subtracts the entered put premium from the entered call premium and compares that amount with discounted spot minus discounted strike. A result near zero means the manually entered values satisfy the disclosed identity within numerical and input precision. A positive or negative residual only shows the direction of that arithmetic difference.

The two forward diagnostics rearrange the same relationship. Rate-parity forward uses spot and the two entered continuous rates. Premium-implied forward uses strike and entered call-minus-put premium after undoing quote-currency discounting. Matching values are another representation of a near-zero residual, not independent market evidence.

Both premiums must use the same unit and timestamp. Combining a call ask with a put bid, quotes observed at different times, different exercise styles, different expiry cuts, different settlement terms or different premium currencies violates the matched-contract assumption even if each input is individually real.

A displayed residual is not an executable arbitrage opportunity. A real conversion or reversal requires synchronized tradable prices, financing, ability to transact in the underlying or forward, collateral, exercise and settlement mechanics, taxes, credit capacity and enough size after costs. This page observes none of those conditions.

The direct base notional multiplies the per-unit residual only to make scale visible. It does not infer a standard lot, exchange contract multiplier or executable quantity. Actual OTC, exchange and broker products can use different deliverables, ticks, premiums and settlement conventions.

Worked example from the audited fixture

Reproduce it with “Load audited example”

The audited fixture uses EUR/USD spot 1.10000, strike 1.12000, 4% USD quote-currency continuous rate, 2% EUR base-currency continuous rate, 180 days on a 365-day basis and EUR 100,000 reference notional.

Entered call premium is USD 0.0324689310779 per EUR and entered put premium is USD 0.0413882467444 per EUR. Call minus put is −0.0089193156665, while discounted spot minus strike is the same within floating-point precision.

The displayed residual rounds to zero. Both the rate-parity forward and premium-implied forward are 1.11090299. Those values reproduce one consistent model fixture; they are not a live forward or arbitrage test.

How to interpret the result

  1. Confirm the call and put are truly matched before reading the residual. Same currency symbols alone are not enough.
  2. Treat a tiny residual as numerical consistency with the disclosed identity, not proof that either premium is fair or executable.
  3. Treat a material residual as a prompt to recheck units, timestamp, rate orientation, exercise style, strike, expiry cut and settlement before considering any market explanation.
  4. Use the total residual only as the per-unit difference multiplied by entered notional. It is not attainable profit and contains no transaction or financing costs.
  5. Compare both forward diagnostics as a secondary arithmetic check; neither value is a dealer quote, deliverable forward price or accounting fair value.
  6. Use the pricing calculator when volatility is known and a theoretical premium is needed; parity itself does not require volatility.

Which FX option analysis tool answers which question?

These tools share governed European FX-option arithmetic but keep three different user jobs separate. A scenario changes one option state, parity checks matched premiums, and portfolio Greeks aggregate local multi-leg exposures.

Comparison of the three FX option analysis tools
ToolRequired entered dataOutputHard boundary
Price scenarioOne option, entered premium and two model statesBefore-expiry model P&L scenarioNo forecast or executable close
Put-call parityMatched call/put premiums, spot, strike, rates and timeDiscounted consistency residualNo executable-arbitrage verdict
Portfolio GreeksShared pair state plus one to twenty option legsSigned premium, delta, gamma and vegaNo account retrieval or hedge instruction

Assumptions and limitations

  • No option chain, bid, ask, spot feed, forward feed, yield curve, account, contract, position, order, exercise or settlement system is connected.
  • European same-contract parity is assumed. American exercise, barriers, digitals, differing collateral and settlement mismatches are excluded.
  • Rates are entered as constant continuously compounded annual rates for the entered horizon; term structures and funding asymmetry are omitted.
  • Bid-ask spread, commissions, tax, funding, collateral, credit, liquidity, borrow, conversion and operational costs are not calculated.
  • A residual can reflect inconsistent or stale manual inputs. The tool cannot distinguish data error from a market or convention difference.
  • No arbitrage, fair value, premium, forward, option, provider, broker, hedge, strategy, signal or trade is recommended or certified.

Sources and methodology

The arithmetic is independently fixture-tested. These primary references define formulas and sensitivity meanings; they do not verify an entered premium, quote, contract, provider, position or market timestamp.

Frequently asked questions

  • It compares entered call minus put premium with discounted spot minus discounted strike for matched European options.
  • Yes. They must also share the same underlying orientation, expiry, exercise style, settlement assumptions and observation time.
  • No. The identity uses matched premiums, spot, strike, two discount rates and time; volatility is not an input.
  • It means the entered values satisfy the disclosed discounted identity within numerical and input precision.
  • No. Executable arbitrage depends on synchronized tradable prices, spreads, funding, collateral, taxes, credit and settlement that this page does not observe.
  • They are equivalent rearrangements of parity: one from spot and rates, the other from strike and the entered premium difference.
  • That creates a particular executable-side comparison only if every other leg and cost is synchronized and tradable; this calculator does not verify that setup.
  • No. It is only the per-unit arithmetic residual multiplied by the entered base notional.

Compare Top Forex Brokers

Before comparing a model result with any broker or provider, confirm whether the product is offered in your jurisdiction and verify the option style, premium unit, notional, expiry, settlement, spreads, commission, collateral and risk disclosures.

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Disclaimer: The results from this tool are estimates for educational and informational purposes only and may differ from your broker's figures. This is not financial or investment advice. Trading forex and CFDs carries a high level of risk and can result in the loss of all your capital. Always verify calculations with your broker and trade within your risk tolerance.