How the historical calculator works

USDT is counted at par against the US dollar (1 USDT = 1.00 USD). The Argentine peso value uses the official BCRA Comunicación A3500 wholesale reference rate. The informal (blue) market reference comes from a separate informal-market series and is shown only as context. Each rate is read from the production fx_rates store, where every row is backed by a dated source-evidence record.

• Verified USDT to ARS coverage starts 2015-03-06. Earlier dates fail closed as outside verified coverage.

Every input is a calendar date. Crypto reference prices are the daily reference price at 00:00 UTC for that date; the FX rate is the official published rate for that date. The same input gives the same answer next year — reproducibility is the point.

When a source does not publish on a date (weekends, holidays, or an explicit no-publication notice), the rate is carried forward from the prior business day and always labeled with that source business date. Today and future dates are refused, because official rates are not yet final.

Default math is amount × 1.00 USD (par) × FX(date). Par is a methodology convention for this calculator, not a guarantee of market price; it matches the nominal USD-pegged amount the product books for wallet flows.

Whenever the token's daily market price deviated from par by 0.25% or more, the result automatically adds a depeg disclosure that shows both the par-basis value and the market-basis value for that date, so the answer is honest on exactly the dates a reader would check. The 0.25% threshold clears normal daily noise and still catches the real events.

For ARS the calculator always renders two labeled values. Official — BCRA A3500 is what Argentine accounting practice references and what TxFlows Flow Statements use. Blue — informal market reference is shown as market context only: it is explicitly not an official rate and not bookable guidance. One sentence sits between them so the distinction is never ambiguous.

A network fee is paid in the chain's own native token, so it is valued as fee amount × native_USD_price(date) × FX(date). Native tokens have no peg, so the fee always uses the actual daily market price of that token and labels its date and source. We never estimate or fabricate a typical fee.

All math runs on decimal strings — no binary floating point anywhere in the calculation path. Fiat values display at two decimal places (four when below 0.01 for micro-fees), rates at their full published precision, and token amounts as entered. Rounding is applied once, at display only; the CSV export carries the full-precision values exactly as computed, so the rounded page figures can always be re-derived from the source numbers.

1. A missing rate or price for a valid date returns an explicit “no verified data” answer. We never interpolate and never silently substitute an adjacent date.
2. Carried-forward and fallback-sourced rates are always labeled in the result and the CSV.
3. A degraded backend says so and shows nothing numeric.
4. Every displayed rate is traceable to an evidence row — the central claim of this page, true by construction.