Calculation standards
Calculation logic is separated from presentation. Each tool documents its formula, example assumptions, validation conditions and rounding approach. Currency results are normally displayed to two decimal places; quantities are rounded only when whole tradable units are required.
Sources and changing rates
Pure mathematical formulas do not require external rates. Brokerage, taxes, exchange rules and regulatory values can change and must be supported by authoritative sources before publication. Users should confirm time-sensitive values with the relevant broker, exchange or government authority.
Limitations
Calculators cannot model every spread, slippage event, liquidity constraint, funding charge, tax situation or execution rule. Results are scenarios—not forecasts.
Corrections
If an error is identified, the affected calculation and explanation should be reviewed together. Material corrections should update the page’s reviewed date and calculation tests.
Testing and validation
Pure calculation functions are checked against hand-worked examples, boundary values and invalid inputs. Tests cover long and short directions, zero-return scenarios, fractional periods, fees, lot rounding and capital depletion where relevant. Interface checks confirm that controls, tables and downloads reflect the calculation output.
Rate versioning
Broker-specific rates include a verification date and official source. A missing or uncertain tariff is shown as unavailable instead of being treated as zero. Because exchanges, taxes and plans change, dated comparisons should be confirmed before a trade.