Currency Calculator
Convert currencies offline using your own exchange rate or bundled dated reference rates. No external API is contacted.
Convert using a user-supplied rate. This rate is not live market data.
Result
Manual rate: USD → EUR. No live quote is implied.
How to use this calculator
Convert using a user-supplied rate. This rate is not live market data. Enter amounts in the units shown, select the applicable options, and click Calculate. Use Reset to restore the starting values.
Calculation formula
Converted = source amount × exchange rate.
Assumptions and accuracy
Review timing, rates, fees and result notes when comparing scenarios. Future returns and rates are assumptions rather than guaranteed outcomes. Monetary display follows the currency’s precision; intermediate calculations retain additional digits.
Choose what to calculate
Currency converter with custom exchange rate
Convert money using your own exchange rate or bundled dated reference rates. No external API is contacted and historical snapshots are not live market prices.
Open this calculationUnderstanding this calculation
Convert currencies offline using a manually supplied exchange rate or a dated snapshot bundled with this site. No external API requests are made.
Worked examples
Convert USD to EUR using a custom exchange rate
Illustrative inputs are specified in the steps below; the example link loads the complete settings. Unmentioned settings use the linked defaults.
- At a manually entered 0.90 EUR per USD, multiply 100 USD × 0.90 = 90 EUR. This rate is illustrative, not a live quote.
Converted amount: 90 EUR.
Try these inputsCommon questions
How do I enter a custom exchange rate?
Select source and target currencies, then enter target units per one source unit. At 0.90 EUR per USD, 100 USD converts to 90 EUR.
Does this show the amount my bank will pay?
Not necessarily. Banks and payment providers may apply spreads and fees that are not included in the reference rate.
Does this currency converter work without a live exchange-rate API?
Yes. Custom Exchange Rate uses the rate you enter; Saved Reference Rates uses historical data bundled with the site and displays its dates. Neither mode requests external data. Snapshots do not update automatically and do not represent an executable bank quote; BTC conversion requires a manual rate.
Scope and assumptions
Saved rates are historical references, not live or executable quotes. Update the site bundle to change the snapshot, or enter your own rate. Fees and spreads are excluded.
Sources
- Calculation methodology, rule versions and testing limitations
- Reference calculator for feature comparison (not a model-parity certification)
Calculation notes checked . Examples are mathematical checks under the stated assumptions.
Calculation methods and formulas
Custom Exchange Rate
Convert using a user-supplied rate. This rate is not live market data.
Converted = source amount × exchange rate.
Saved Reference Rates
Convert using the dated reference-rate snapshot bundled with this application. This is not a live quote.
Cross rate = USD-to-target reference / USD-to-source reference.
See our calculation methodology and review status for data versions, rounding and validation limitations.