Free Online Crypto Unit Converter, Satoshi, Bitcoin, Gwei, Wei & Ether
Convert between the small units and the whole coin. Satoshi to Bitcoin, wei and gwei to Ether, and back again, with the exact number of zeros rather than a rounded one. Handy when a gas fee is quoted in gwei or a small amount is quoted in sats and you need the real value.
Unit conversions are mathematical calculations and do not represent cryptocurrency prices or exchange rates. Everything is worked out locally in your browser.
₿ Crypto unit converter
Any unit to any unit, exactly.
₿ Bitcoin units
BTC, mBTC, bits and satoshis.
₿ Satoshi converter
The smallest unit Bitcoin has.
♦ Ethereum units
ETH down to wei, and back.
♦ Wei converter
Eighteen decimal places, all of them.
♦ Gwei converter
The unit gas prices are quoted in.
📏 Large numbers
Thousands to quintillions.
% Percentage converter
Decimal, percent and per mille.
% Basis points
One hundredth of one percent.
🔥 Gas unit calculator
Gas limit multiplied by gas price. The multiplication is exact; what a transaction actually costs is not this tool's to know.
🔢 Token decimals
Human amount to base units.
🔬 Scientific notation
Plain, scientific and engineering.
✨ Crypto number formatter
The same number, presented four ways.
💵 Crypto amount and fiat
At the price you enter, both directions.
📋 Batch converter
A whole list at once. Each row keeps its own unit, and every row is converted into the target unit you pick.
| # | Amount | From unit | Result |
|---|
🛠️ Your own units
A unit this tool does not know about. Give it a name and say how many base units it is worth, and it joins the family you pick.
| Name | Symbol | Family | Base units | Actions |
|---|
| When | Converter | Input | Result | Actions |
|---|
Converter
Number formatting
Precision only limits what is shown. The conversion itself is always done on whole numbers at full precision, and when a rounded display would hide something that matters, the result is flagged rather than trimmed quietly.
Currency
A display unit only. No exchange rate is applied anywhere in this tool, so switching currency changes the symbol, not the numbers.
Results
Appearance
History
Your data
Settings, history, favourites and custom units are stored only in this browser. Nothing is uploaded, and this tool has no field for a wallet address, an API key, a private key or a seed phrase. A unit converter has no use for any of them.
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How to Use the Unit Converter
Five steps, and the last one is the one that saves money.
Bitcoin units, Ethereum units, plain numbers or percentages. Units never cross families here, which is deliberate. It is the reason a Bitcoin finney can never be mistaken for an Ethereum one.
Plain digits, commas, or scientific notation. 1, 1.5, 0.00000001 and 1.5e18 are all read the same way, and none of them loses a digit on the way in.
The swap button reverses the two units and keeps your input exactly as it was. Retyping a long number is where mistakes get made.
The result panel lists the same amount in every unit of that family. It is the fastest way to catch an order-of-magnitude slip, which is the only kind of error that really costs anything here.
Do not assume 18. USDC uses 6 and WBTC uses 8, and getting that wrong is not a small error. It is out by a factor of a trillion.
Why the Last Few Digits Matter
8.7 ETH into wei. The answer is not in doubt, but how you get there decides whether you arrive.
| How it is calculated | What happens | Result in wei |
|---|---|---|
| Floating point | 8.7 cannot be written exactly in binary, so the multiplication starts from a value that is already slightly off. | 8699999999999999000 — close, and wrong |
| Floating point, on 0.1 ETH | The same method on a different input happens to land exactly right, which is what makes it dangerous. Nothing about the input tells you which case you are in. | 100000000000000000 — right by luck |
| Integer with a scale | The digits 87 and a scale of 1 are stored separately, and converting moves the scale by 18. Nothing is ever approximated. | 8700000000000000000 — right by construction |
The middle row is the dangerous one. Same method, same code, and it happens to be exactly right, so a converter built that way passes every casual check you would think to make, and fails on some other number you have not tried yet. Try 1.1 BTC in satoshis and a float gives you 110000000.00000001: a fractional satoshi, in a unit that has no fractions. That is why this tool takes the third route everywhere, rather than only where the problem happened to show up.
The Numbers, Written Out in Full
Copy them straight from here if that is all you came for.
Bitcoin
Base unit: sat
| One of | Is this many sat |
|---|---|
| BTC | 100,000,000 |
| mBTC | 100,000 |
| μBTC | 100 |
| bits | 100 |
| finney | 10 |
Ethereum
Base unit: wei
| One of | Is this many wei |
|---|---|
| ETH | 1,000,000,000,000,000,000 |
| finney | 1,000,000,000,000,000 |
| szabo | 1,000,000,000,000 |
| gwei | 1,000,000,000 |
| mwei | 1,000,000 |
| kwei | 1,000 |
Large numbers
Base unit: one
| One of | Is this many one |
|---|---|
| quintillion | 1,000,000,000,000,000,000 |
| quadrillion | 1,000,000,000,000,000 |
| trillion | 1,000,000,000,000 |
| billion | 1,000,000,000 |
| million | 1,000,000 |
| thousand | 1,000 |
Three of those figures cover most of what anyone actually needs. 1 BTC is 100,000,000 satoshis,
eight decimal places and not one more. 1 ETH is 1,000,000,000,000,000,000 wei, eighteen places.
1 gwei is 1,000,000,000 wei, which is why gas prices are quoted in gwei rather than in ether, where
they would be an unreadable string of zeros, or in wei, where they would be a number too long to say.
Two things worth knowing while you are here. There is nothing below a satoshi or below a wei, so a
"fraction of a satoshi" is a display artefact rather than something the chain can hold. And the finney
appears in both columns meaning two completely different sizes: ten satoshis on Bitcoin, a thousandth of
an ether on Ethereum. If you are reading someone else's figures, check which chain they were on before you
trust the unit.
Every Conversion, Written Out
All of them are the same one line: a shift by the difference of two exponents.
| Conversion | Formula | Worked example |
|---|---|---|
| Any conversion | Input × 10^(fromExp − toExp) |
The whole engine is this one line |
| BTC to satoshi | BTC × 10⁸ |
1 BTC = 100,000,000 sat |
| Satoshi to BTC | sat ÷ 10⁸ |
1 sat = 0.00000001 BTC |
| BTC to mBTC | BTC × 10³ |
1 BTC = 1,000 mBTC |
| BTC to bits | BTC × 10⁶ |
1 BTC = 1,000,000 bits, the same as 1,000,000 μBTC |
| ETH to wei | ETH × 10¹⁸ |
1 ETH = 1,000,000,000,000,000,000 wei |
| ETH to gwei | ETH × 10⁹ |
1 ETH = 1,000,000,000 gwei |
| Gwei to ETH | gwei ÷ 10⁹ |
25 gwei = 0.000000025 ETH |
| Gwei to wei | gwei × 10⁹ |
25 gwei = 25,000,000,000 wei |
| Gas cost | Gas Limit × Gas Price |
21,000 × 25 gwei = 525,000 gwei |
| That gas cost in ETH | Gas Cost in gwei ÷ 10⁹ |
525,000 ÷ 10⁹ = 0.000525 ETH |
| Human amount to base | Amount × 10^decimals |
1.5 at 18 decimals = 1500000000000000000 |
| Base amount to human | Base ÷ 10^decimals |
1500000 at 6 decimals = 1.5 |
| Decimal to percent | Decimal × 10² |
0.05 = 5% |
| Percent to basis points | Percent × 10² |
5% = 500 bps |
| Decimal to basis points | Decimal × 10⁴ |
0.05 = 500 bps |
| Scientific notation | d.ddd × 10ⁿ |
0.000000001 = 1 × 10⁻⁹ |
| Crypto to fiat | Amount × Price You Entered |
0.5 × $100,000 = $50,000 |
| Fiat to crypto | Fiat ÷ Price You Entered |
$10,000 ÷ $100,000 = 0.1 BTC |
Unit Reference
Every unit this tool knows, and exactly what it is worth in its family's base unit.
₿ Bitcoin · base unit: Satoshi
| Unit | Symbol | In base units | What it is |
|---|---|---|---|
| Bitcoin | BTC | 108 | The unit everyone quotes. One BTC is 100,000,000 satoshis, eight decimal places and no more. |
| Milli-bitcoin | mBTC | 105 | A thousandth of a bitcoin, 100,000 satoshis. Once common on exchanges, now rare. |
| Micro-bitcoin | μBTC | 102 | A millionth of a bitcoin, 100 satoshis. Exactly the same size as a "bit" — two names for one unit. |
| Bits | bits | 102 | The friendlier name for a micro-bitcoin. 1 bit = 100 satoshis, and it is the same thing as μBTC. |
| Finney | finney | 101 | Ten satoshis, named after Hal Finney. Informal and rarely used, and not the same finney as the Ethereum one. |
| Satoshi | sat | 1 | The base unit. 0.00000001 BTC, and the smallest amount Bitcoin can represent. |
♦ Ethereum · base unit: Wei
| Unit | Symbol | In base units | What it is |
|---|---|---|---|
| Ether | ETH | 1018 | The unit everyone quotes. One ether is 1,000,000,000,000,000,000 wei. |
| Finney | finney | 1015 | A thousandth of an ether, also called milliether. Not the same as the Bitcoin finney, which is ten satoshis. |
| Szabo | szabo | 1012 | A millionth of an ether, also called microether. Named after Nick Szabo. |
| Gwei | gwei | 109 | A billionth of an ether. This is the unit gas prices are almost always quoted in. |
| Mwei | mwei | 106 | A millionth of a gwei. Also called lovelace or picoether. Rarely seen. |
| Kwei | kwei | 103 | A thousand wei. Also called babbage or femtoether. Rarely seen. |
| Wei | wei | 1 | The base unit, named after Wei Dai. Everything on chain is an integer count of these. |
📏 Large numbers · base unit: Units
| Unit | Symbol | In base units | What it is |
|---|---|---|---|
| Quintillion | quintillion | 1018 | A million million million. The same size as one ether in wei. |
| Quadrillion | quadrillion | 1015 | A thousand trillion. |
| Trillion | trillion | 1012 | A thousand billion. Total crypto market capitalisation is usually quoted here. |
| Billion | billion | 109 | A thousand million, on the short scale. |
| Million | million | 106 | A thousand thousand. |
| Thousand | thousand | 103 | A thousand. |
| Units | — | 1 | The plain number, with nothing scaled. |
% Percentages · base unit: Basis points
| Unit | Symbol | In base units | What it is |
|---|---|---|---|
| Decimal fraction | — | 104 | The plain fraction a formula uses. 0.05 is five percent. |
| Percent | % | 102 | One hundredth. 5% is 0.05 as a fraction and 500 basis points. |
| Per mille | ‰ | 101 | One thousandth. Ten basis points, and half as common as it used to be. |
| Basis points | bps | 1 | One hundredth of one percent. 100 bps is 1%. |
What This Converter Will Not Tell You
The limits are part of the tool, not the small print.
What This Tool Does
Every value is held as an integer with a recorded scale and converted by moving the decimal point. No floating-point number appears anywhere on the conversion path, so 1 ETH becomes 1000000000000000000 wei down to the final digit.
Bitcoin, Ethereum, large numbers and percentages. Units cannot cross between them, which is what stops a Bitcoin finney and an Ethereum finney, twenty-four orders of magnitude apart, from ever meeting.
Gas limit times gas price, shown in wei, gwei and ETH together, with the arithmetic written out. Labelled as arithmetic rather than as a quote, because the real cost depends on the block.
Human amount to base units and back, at whatever precision the contract actually uses. Both boxes are live, so fill in either one and the other follows.
A whole list converted at once, the pairs you use daily saved to hand, and everything you have converted kept for reuse, all in this browser, none of it anywhere else.
Not a single request leaves the page. The conversions need nothing external, and the only price involved anywhere is the one you type on the fiat tab.
About the Crypto Unit Converter
Converting between crypto denominations sounds like the least interesting thing a calculator can do. Multiply by a hundred million, move on. The reason this tool exists is that a surprising number of converters get it wrong in the last few digits, and in this particular corner of arithmetic the last few digits are the only ones that matter.
The cause is always the same. JavaScript numbers are binary floating point, and most decimal fractions cannot be written exactly in binary, which is why 0.1 + 0.2 famously comes out as 0.30000000000000004. What makes it genuinely dangerous in unit conversion is that it is intermittent. Multiply 0.1 by 10¹⁸ in a float and you get the right answer. Do the same with 8.7 and you get 8699999999999999000 instead of 8700000000000000000. Try 1.1 BTC in satoshis and a float produces 110000000.00000001 — a decimal place in a unit that has none. Nothing about the input tells you which case you are in.
The way out turns out to be elegant rather than laborious. Every crypto denomination is a power of ten of its base unit: a bitcoin is 10⁸ satoshis, an ether is 10¹⁸ wei, a percent is 10² basis points. Converting between two of them is therefore not a multiplication at all; it is moving the decimal point by the difference of two exponents. Held as an integer with a recorded scale, that operation is exact by construction, and the whole engine here is one line of arithmetic applied to whole numbers.
The rest of the module is built on the same principle of not quietly deciding things for you. Unit families are kept strictly apart, so the Ethereum finney and the informal Bitcoin finney, twenty-four orders of magnitude apart and both named after the same person, can never meet. Amounts too precise for the target unit are flagged rather than trimmed. Gas costs are labelled as arithmetic rather than quotes. And the only price anywhere in the tool is the one you type, because a unit conversion is a fact about the protocol and has nothing to do with what anything is worth.
Frequently Asked Questions
The questions behind the questions.