How currency conversion works
A currency converter calculates the equivalent value of one monetary unit in another denomination, whether fiat or digital. At its core, multiply the amount by the current exchange rate. Accuracy depends on ISO 4217, the global standard assigning three-letter codes (USD, EUR, GBP, JPY) to every official currency. Cryptocurrencies like BTC, ETH, and SOL follow the same convention in the industry. The Veloxcalc Currency Converter supports 30 major fiat currencies and 12 popular cryptocurrencies, using live mid-market rates with ISO-compliant rounding. For US travelers and businesses, proper conversion matters for expense reports, customs declarations, and IRS-compliant foreign income translations on Form 1040 and Form 2555.
The mid-market rate and retail spread
The mid-market (interbank) rate is the midpoint between wholesale buy/sell prices—what you see on Google or Reuters. In practice, banks and FX services add a retail margin. The EBA documents spreads of 0.2% to 3% depending on the provider, with 0.5% as a rough industry average for major pairs. Example: €1,000 EUR → USD at a mid-market rate of 1.085 yields $1,085.00. The inverse rate is 0.92165 EUR per USD. A 0.5% typical retail spread creates a low/high band of ~$1,079.58 to ~$1,090.43, implying an effective spread fee of about $5.425. The Veloxcalc converter displays both the clean mid-market figure and a realistic retail estimate so users understand true conversion costs.
Fractional digits: why JPY has no decimals but BTC has 8
Fiat codes and their precision (2 for USD/EUR, 0 for JPY/KRW)
ISO 4217 also specifies the number of fractional digits per currency. Most major fiat currencies (USD, EUR, GBP, MXN) use 2 decimal places because the smallest coin equals one hundredth of the base unit. However, JPY, KRW, and IDR use 0 fractional digits because no active coin or banknote is smaller than one base unit. The Veloxcalc converter strictly adheres to these standards, automatically rounding USD to 2 decimals and JPY to whole integers.
Cryptocurrency precision (8 decimals for BTC/ETH/SOL)
Unlike fiat, most cryptocurrencies are divisible far beyond 2 decimals. Bitcoin's smallest unit is the satoshi: 0.00000001 BTC (8 decimal places). Ethereum and Solana use the same eight-decimal convention in consumer interfaces. Stablecoins such as USDT and USDC typically display with 4 decimals because they track the US dollar 1:1. The converter preserves these conventions: 8 decimals for BTC, ETH, and SOL, and 4 decimals for USDT and USDC. This precision matters for small transfers and tax records.
The 0.5% typical retail spread estimate
The converter includes a default 0.5% spread estimate, adjustable for specific providers. This helps US small businesses, freelancers, and overseas contractors, where hidden FX fees often eat into margins. The EBA's EU transparency rules and US Dodd-Frank remittance disclosures require showing margins, but many consumers still overlook the impact of even a 0.5% fee on large transfers. Always compare converted amounts against the mid-market baseline. All Veloxcalc outputs are estimates for informational purposes only and do not reflect real-time tradable rates from any bank, broker, or exchange.