Why a cash U.S.-dollar market and a Tether-quoted market can look similar without being the same instrument or risk. The checks below separate measured market facts from forecasts and personal decisions.
- USD and USDT are different quote assets.
- Separate order books can produce different prices.
- A stable target is not the same as a cash-dollar guarantee.
USD is a fiat currency
USD refers to U.S.-dollar money held within the banking and cash system. On an exchange, a USD balance is a claim governed by that venue's banking, custody, account, and withdrawal arrangements. A BTC/USD order book records bids and offers denominated in that fiat unit.
USDT is an issued token
USDT is a stablecoin issued by Tether across supported blockchains. It targets one U.S. dollar and is widely used as a crypto-market quote asset, but it adds issuer, reserve, redemption, network, and token-contract dependencies that cash dollars do not share in the same form.
Name the market and the timestamp. A BTC/USD trade, a BTC/USDT quote, and a multi-venue reference are related observations, not interchangeable prices.
Why prices can diverge
BTC/USD and BTC/USDT trade in separate order books with different participants, funding routes, liquidity, and jurisdictional access. USDT can trade slightly above or below a dollar, and venue demand can move one Bitcoin pair before another.
How Bitcoin.now labels the data
The headline Bitcoin.now BTC/USD reference uses actual BTC/USD observations from Coinbase Exchange, Kraken, and Bitstamp. BTC/USDT from OKX and MEXC appears separately for broad public market coverage and is never silently renamed as exact USD.
Two things a price can be quoted in
A dollar in a bank is a liability of an insured institution within a legal system that guarantees it up to a limit. A USDT token is a liability of a private company that holds reserves and promises redemption to eligible customers.
Both are 'dollars' on an exchange screen, and on most days the market prices them within a fraction of a percent of each other.
They are not the same instrument, and a price expressed in one is not a price expressed in the other, in the same way that a price in euros is not a price in dollars even when the exchange rate is stable.
When the gap appears
USDT has traded below a dollar during episodes of doubt about its reserves and above a dollar during rushes into crypto markets when fiat on-ramps were slow. USDC traded near 88 cents for a weekend in March 2023 after a reserve bank failed. On those days a BTC/USDT price and a BTC/USD price told different stories, and a blended 'bitcoin price' would have told neither.
Because those are the days when readers most need an accurate number, this site refuses to blend them: the USD reference draws only from fiat venues, and USDT markets are shown with their quote asset.
Which to use for what
Use a fiat quote to understand what bitcoin is worth in money you can spend, for tax records, and for any comparison over time. Use a USDT quote to understand what you would actually pay or receive on a venue that trades in USDT, which is most of the world's crypto-to-crypto volume.
Never compare the two without checking the token's own price that day. The methodology page on this site explains how each reference is built, and the stablecoin monitor shows the token's current distance from a dollar.
Check the market claim before acting
Write down the pair, venue, timestamp, spread, and source behind a number. A historical pattern or current reference is evidence about a market observation, not a promise about the next price.
Common questions
Why does Bitcoin.now show BTC/USD separately from BTC/USDT?
Because they are different markets with different quote assets. A dollar is cash in a bank; USDT is a token whose value depends on its issuer's reserves and redemption. Mixing them hides that difference, which matters most when it is largest.
Is USDT backed one-to-one by dollars?
The issuer publishes attestations describing reserves of cash, Treasury bills and other assets it says exceed the tokens outstanding. Those are the issuer's own disclosures reviewed by an accounting firm, not a government guarantee or a full audit.
How far apart are BTC/USD and BTC/USDT usually?
Normally within a fraction of a percent, because arbitrage keeps them aligned. The gap widens during stress — when USDT itself trades away from a dollar or when fiat withdrawals are constrained — which is exactly when a single blended price would mislead.
Sources and further reading
Primary documents this guide draws on. Links open the original publisher.
- Tether transparency and reserves Tether
- What is the money supply? Is it important? Board of Governors of the Federal Reserve System
- Deposit insurance U.S. Federal Deposit Insurance Corporation