Bitcoin Unit Converter

What is Bitcoin Unit Converter?

Bitcoin Unit Converter helps you convert between different denominations of Bitcoin (BTC). The smallest unit is a Satoshi (sat), named after Bitcoin's creator, Satoshi Nakamoto. This tool supports all common Bitcoin units and provides fiat currency conversion for practical value estimation.

1 Bitcoin = 100,000,000 Satoshis. Understanding these units is essential for Bitcoin transactions, fee calculations, and price analysis.

Bitcoin Units Explained

What is a satoshi and why is it the base unit of Bitcoin?

A satoshi (sat) is the smallest indivisible unit of Bitcoin, named after the pseudonymous creator Satoshi Nakamoto. By protocol design, 1 BTC = 100,000,000 satoshis (10^8), making the satoshi the on-chain accounting unit. Bitcoin Core stores all transaction values internally as integer satoshis to avoid floating-point precision errors that would be catastrophic for money. When you see a balance of 0.00123456 BTC, the network actually records it as 123,456 satoshis. Fees are quoted in sats/vByte, Lightning Network amounts use millisatoshis (1 sat = 1000 msat) for sub-satoshi routing precision, and Ordinals/inscriptions reference individual satoshis by their mint order. Always think in satoshis when accuracy matters.

How do mBTC, bits, and μBTC relate to each other?

These are SI-style sub-units of Bitcoin. 1 mBTC (millibitcoin) = 0.001 BTC = 100,000 satoshis. 1 bit, also written μBTC (microbitcoin), = 0.000001 BTC = 100 satoshis. So 1 mBTC = 1,000 bits = 100,000 sats. The BIP 176 proposal in 2017 standardized "bits" as the human-friendly small unit because numbers like "500 bits" feel more intuitive than "0.0000050 BTC." Exchanges and wallets pick different defaults: many European exchanges historically displayed mBTC; Lightning wallets prefer sats; institutional reports use full BTC. Pick the unit whose typical transaction size produces 1-1000 digits to avoid both leading zeros and scientific notation.

Why does Bitcoin have exactly 8 decimal places?

Satoshi Nakamoto chose 8 decimal places in the original 2009 Bitcoin Core code as a balance between divisibility and storage efficiency. Each satoshi fits in a signed 64-bit integer (max ~9.2 * 10^18), which comfortably handles the full 21 million BTC supply (2,100,000,000,000,000 sats) with room to spare. Eight decimals gives roughly the same precision per dollar as fiat cents would give at a BTC price near $100 million — meaning satoshis remain economically meaningful even in extreme bull scenarios. The 21 million cap and 8-decimal precision are consensus rules: changing them would require a hard fork that splits the network, which is why proposals for finer divisibility instead use off-chain layers like Lightning's millisatoshis.

How do I calculate Bitcoin transaction fees in satoshis per vByte?

Modern Bitcoin fees use sat/vB (satoshis per virtual byte), where vBytes account for SegWit's witness discount (witness data counts as 1/4 weight unit). Total fee = transaction_vsize * fee_rate. A typical 1-input, 2-output P2WPKH (native SegWit) transaction is around 140 vBytes; at 20 sat/vB that's 2,800 sats. Multisig and Taproot transactions vary: a 2-of-3 P2WSH is ~190 vBytes, a single-key Taproot spend is ~110 vBytes. During mempool congestion (e.g., Ordinals bursts in 2024) rates spiked above 500 sat/vB, while quiet periods sit at 1-5 sat/vB. Use mempool.space to check current rates and target a confirmation block.

What is the difference between satoshis and Lightning millisatoshis?

On-chain Bitcoin's smallest unit is the satoshi, but the Lightning Network introduced millisatoshis (msat) for off-chain routing precision: 1 sat = 1,000 msat. Lightning payments and routing fees can be priced in fractional satoshis because they're recorded in commitment transactions that round to whole satoshis only when channels settle on-chain. This matters for tiny payments like per-second video streaming (0.1 sat/sec) or paying for each AI token consumed. BOLT specifications require nodes to handle msat-precision invoices, but on-chain closing transactions can only express integer satoshis, so dust amounts below the dust limit (typically 354 sats for P2WPKH) get burned to miner fees during channel closure.

How should I store Bitcoin amounts in code to avoid rounding errors?

Always store and arithmetic Bitcoin amounts as integer satoshis, never as floating-point BTC. JavaScript's Number type uses IEEE 754 doubles with 53 bits of mantissa, which can exactly represent integers up to 2^53 = 9.0 * 10^15 — more than enough for the 2.1 * 10^15 satoshis ever to exist, but only if you keep them as integers. Computing 0.1 + 0.2 in BTC gives 0.30000000000000004; the same as 10000000 + 20000000 sats gives exactly 30000000. For amounts crossing 2^53 (rare in practice), use BigInt or libraries like bignumber.js. Convert to display units (BTC, mBTC) only at the rendering layer, never for math, comparisons, or database storage.

Is Bitcoin's 21 million supply cap really unchangeable?

Technically the 21M cap is a consensus rule enforced by every node's code, not a law of physics — but changing it requires a hard fork accepted by miners, exchanges, wallet developers, and the economic majority. Any node running unmodified Bitcoin Core would reject blocks that produce more than the scheduled subsidy (currently 3.125 BTC/block after the April 2024 halving, halving every 210,000 blocks). The cap is socially stronger than the code: Bitcoin's value proposition explicitly depends on monetary scarcity, so a proposal to raise the cap would likely cause a contentious split where the original-supply chain retains the "Bitcoin" name and most value. The last satoshi is projected to be mined around year 2140, after which miners survive on fees alone. Not financial advice.

How do Ordinals and inscriptions identify individual satoshis?

The Ordinals protocol (launched January 2023 by Casey Rodarmor) assigns a unique serial number to every satoshi based on the order it was mined, creating ~2.1 * 10^15 numbered sats. The numbering scheme uses degree notation (e.g., 1*65,000,000*0*0*0) encoding cycle/epoch/period/block/offset, and rare sats include the first sat of each block ("uncommon"), first sat after a halving ("epic"), first sat of a difficulty adjustment period ("rare"), and sat #0 itself (the "mythic" genesis sat held by Satoshi). Inscriptions attach arbitrary data (images, text, JSON) to a specific sat via the witness portion of a Taproot transaction. BRC-20 tokens and the Runes protocol (April 2024) extended this idea for fungible tokens directly on Bitcoin L1.

Common Conversion Examples

• 1 BTC = 100,000,000 satoshis
• 1 BTC = 1,000 mBTC (millibitcoin)
• 1 BTC = 1,000,000 bits (microbitcoin)
• 10,000 satoshis = 0.0001 BTC = 0.1 mBTC
• 1 mBTC = 100,000 satoshis = 1,000 bits
• Transaction fee: 5,000 sats = 0.00005 BTC = 0.05 mBTC
• Lightning payment: 1,000 sats = 10,000 millisats