Satoshi to Bitcoin Converter

Converts between satoshis (the smallest Bitcoin unit) and BTC. One bitcoin equals 100,000,000 satoshis; the conversion is a fixed power-of-ten shift. The mBTC (millibitcoin = 100,000 sat) and bit (μBTC = 100 sat) intermediate units are also supported.

The satoshi is named after Satoshi Nakamoto and is the fundamental on-chain accounting unit.

Bitcoin's transaction format stores all amounts as 64-bit signed integers in satoshis. The 100-million-satoshi-per-bitcoin ratio was set in the original 2009 codebase; it gives 21 quadrillion total satoshis once the 21-million-BTC supply cap is reached. The choice was pragmatic: 8 decimal places offer enough granularity to handle micro-payments at any plausible future BTC price while still fitting comfortably in a 64-bit integer with overflow margin. There is no on-chain concept of a 'fractional satoshi'; the consensus rules know only integers.

A worked example: a 0.001 BTC transfer is 100,000 satoshis, also expressible as 1 mBTC. A typical Bitcoin transaction fee at low congestion is 1-10 sat/vByte; for a 200 vByte transaction, that's 200-2,000 sat total fee, or 0.000002 to 0.00002 BTC. At BTC = $60,000, a 1 sat/vByte fee on a small transaction costs about $0.12; during high congestion when fees spike to 200+ sat/vByte, the same transaction can cost $24 or more. Fee-rate awareness is the equivalent of Ethereum's gas-price awareness.

Limitations are mostly about display conventions and Lightning. The mBTC and bit denominations were proposed during 2014-2015 as more readable alternatives to BTC for everyday-sized purchases, but neither achieved widespread adoption. Most exchanges, wallets, and explorers display BTC with 8 decimals or sat as a flat integer, with little use of intermediate units. The Lightning Network uses millisatoshis (10⁻¹¹ BTC) for routing-fee precision, but this finer unit exists only off-chain; settling a Lightning channel onto the base layer rounds to whole satoshis.

Floating-point representation is a real hazard here. JavaScript Number cannot represent 0.1 BTC exactly (the same reason 0.1 + 0.2 ≠ 0.3 in floating point). Using Number for sat-to-BTC conversion at large values introduces rounding error in the final decimal places; production wallet code uses string or integer arithmetic to avoid drift. The tool here uses BigInt for the conversion to preserve exact precision.