Crypto Units & Precision Guide: Sats, BTC, Gwei and ETH
How many sats are in one BTC? Why is gas priced in Gwei? What if order books, APIs and wallets show different units? Convert carefully — “off by a zero” is not a math problem, it is a money problem.
Why unit conversion matters
Across order books, APIs, wallets and on-chain transactions the same amount can appear as coins, base units or dollars. Misreading units is not arithmetic — it is capital: paying gas in ETH when the price is in Gwei, or sizing orders in sats when you mean BTC, costs real money.
Quote precision, contract quantity precision and on-chain gas units differ by venue. Normalizing units before you act is the cheapest layer of risk control.
BTC: one coin equals 100 million sats
1 BTC = 100,000,000 sat (satoshi). The satoshi is Bitcoin's smallest unit; resting orders, Lightning payments and some exchange fees are quoted in sats.
Conversion: USD amount = sats ÷ 100,000,000 × BTC price. Conversely, at a given price, 1 USD ≈ 100,000,000 ÷ price in sats.
ETH: Gwei is the usual gas unit
1 ETH = 10⁹ Gwei = 10¹⁸ wei. On-chain gas price is usually quoted in Gwei; a transaction fee = gas used × gas price.
Example: 21,000 gas × 30 Gwei price = 630,000 Gwei = 0.00063 ETH. Use the Gwei-to-ETH converter to move between unit price and total cost quickly.
Reconciling mixed units
The same position may be shown by an exchange as coins, contracts and USD notional at once. Fees, liquidation and funding are all based on notional — so calculator inputs only make sense once quantities share one unit.
Market-making and API flows demand precision checks: matching engines usually accept base units only, so truncated decimals may leave orders unfilled or fill the wrong size.
Unit conversion in daily workflows
- Convert sat prices to dollar view: the satoshi-to-USD converter turns sats and BTC price into a USD amount.
- Check transfers and chain costs: the Gwei-to-ETH converter turns gas prices into ETH and dollars.
- Across venues or APIs: the BTC unit converter normalizes BTC, mBTC and satoshi quantities.
- Before ordering, rough-check quantity × price against notional to catch decimal errors.
This guide is for educational purposes only and is not investment advice. Always follow your exchange's actual margin, liquidation and fee rules, and keep a buffer for extreme market moves.
FAQ
How many sats are in 1 BTC?
1 BTC = 100,000,000 sats, i.e. 1 sat = 0.00000001 BTC. Order precision follows the venue's minimum step.
How do Gwei and ETH convert?
1 ETH = 10^9 Gwei. Multiply the gas price in Gwei by gas used and divide by 10^9 to get the fee in ETH.
References
Public references behind the mechanics described in this guide, for independent verification.