How many satoshi are in one bitcoin?

One bitcoin equals 100,000,000 satoshi, or 10 to the 8th power. The satoshi is the smallest indivisible unit of Bitcoin. One mBTC (millibitcoin) is one thousandth of a bitcoin, which is 100,000 satoshi.

How many wei are in one ether?

One ether equals 1,000,000,000,000,000,000 wei, which is 10 to the 18th power. Gwei sits in between: one gwei is 10 to the 9th wei, and there are 10 to the 9th gwei in one ether. Gas prices are usually quoted in gwei.

Why does precision matter for wei conversions?

Wei amounts can exceed what a standard JavaScript number represents exactly (about 9 quadrillion). This tool uses big-integer arithmetic for the wei base so large values convert without rounding errors, which is essential when computing exact token amounts.

Is gwei only used for gas?

Gwei is most common for gas prices because typical fees fall in a readable range there, but it is a valid denomination for any amount. You can convert a gas price in gwei to its ether or wei cost and multiply by gas used to get a transaction fee.

Where does the USD value come from?

You enter the exchange rate yourself, so the conversion stays accurate and works offline with no API dependency. Paste the current BTC or ETH price from any source and the tool multiplies it by the bitcoin or ether amount.

Satoshi / Wei / Gwei Unit Converter

Crypto amounts live in many denominations, and mixing them up costs real money. This converter moves a value across all Bitcoin units (satoshi, mBTC, BTC) or all Ethereum units (wei, gwei, ether) at once, with an optional USD value from a price you supply.

How it works

Each chain has a smallest base unit, and every denomination is a fixed power of ten away from it:

Bitcoin base = satoshi
  1 BTC  = 100,000,000 satoshi   (10^8)
  1 mBTC = 100,000 satoshi       (10^5)

Ethereum base = wei
  1 ether = 1,000,000,000,000,000,000 wei  (10^18)
  1 gwei  = 1,000,000,000 wei              (10^9)

The wei base is handled with big integers because an ether expressed in wei has 19 digits — beyond exact floating-point range — so conversions stay precise.

Example and tips

Type 21 gwei and the tool shows 0.000000021 ether and 21,000,000,000 wei instantly; multiply that by your gas limit to price a transaction. On the Bitcoin side, 2,500 satoshi reads as 0.000025 BTC. Always confirm which unit an API or contract expects: Ethereum JSON-RPC returns balances in wei, most explorers display ether, and a one-unit mismatch is a billion-fold error.