97 Fun Facts About Bitcoin

Which carmaker bought $1.5 billion of bitcoin in 2021 and briefly let buyers pay for cars with it?

Tesla stopped accepting bitcoin for cars within two months, citing climate concerns over the fossil fuels burned to mine it.

What is bitcoin's first block, mined by Nakamoto in January 2009, called?

The genesis block's 50-bitcoin reward can never be spent, because the software skips that block's transactions as a special case.

Which newspaper's headline did Nakamoto embed in bitcoin's code in January 2009?

The Times headline said 'Chancellor on brink of second bailout for banks', read both as a timestamp and as a jab at unstable banking.

Who received the first bitcoin transaction, ten coins from Nakamoto in January 2009?

Hal Finney grabbed the software the day it came out; years later, almost paralysed by ALS, he was still writing code to harden bitcoin wallets.

In May 2010, what did programmer Laszlo Hanyecz buy for 10,000 bitcoins?

Laszlo Hanyecz paid 10,000 bitcoins for two Papa John's pizzas, which another forum user ordered and had delivered to his home.

What is the maximum number of bitcoins that will ever be issued?

Only 21 million bitcoins will ever exist, and coins whose private keys are lost can never be spent again, shrinking the usable supply.

What is the event called when bitcoin's block reward is cut, roughly every four years?

The halving comes every 210,000 blocks, which is why the last bitcoin is not expected to be mined until around 2140.

On average, how often is a new bitcoin block created?

Bitcoin targets one block every 10 minutes on average; the difficulty is recalibrated every 2,016 blocks, about two weeks, to hold that pace as mining power changes.

What is the smallest unit of bitcoin called?

The satoshi is one hundred-millionth of a bitcoin, and because bitcoin's price has soared, such tiny units are needed for small purchases.

Which hashing algorithm does Bitcoin use to chain its blocks?

SHA-256 links every block to the one before, so tampering with an old block would mean regenerating every block after it.

What is the consensus process by which miners compete to add blocks called?

Proof of work makes adding a block cost real computing effort, which is hard to produce but easy for everyone else to verify.

What is the special transaction called that pays a miner the block reward?

The coinbase transaction pays the miner the block reward, and every bitcoin in existence was first created through one.

What block size limit did Nakamoto impose, which later fuelled the scaling wars?

Nakamoto added the one megabyte limit in 2010, and years later fights over raising it split the community and led to rival forks.

Which 2017 upgrade aimed to support second-layer payment channels and improve scalability?

Segregated Witness (SegWit) activated in August 2017, moving signature data out of the base block to fix transaction malleability and raise effective capacity, which made payment channels practical.

Which coin split from bitcoin in August 2017 when supporters of bigger blocks forked the chain?

Bitcoin Cash split from bitcoin on 1 August 2017, and it later split again itself when Bitcoin SV broke away.

Which payments company ended bitcoin support in 2018, citing slow transactions?

Stripe said slow confirmations let bitcoin's price swing before a payment settled, leaving some payments for the 'wrong' amount.

Which 2017 ransomware attack, demanding payment in bitcoin, hit hospitals in Britain's National Health Service?

WannaCry was halted when a 22-year-old researcher in England registered a garbled web domain hidden in its code, tripping a kill switch.

Which magazine named a Japanese-American man in California, whose real name matched the pseudonym, as bitcoin's creator in 2014?

Newsweek's cover story named Dorian Nakamoto, who denied any link to bitcoin, and the story drew heavy criticism.

Which self-proclaimed Nakamoto was ruled by a London judge in 2024 not to be him?

Craig Wright had claimed for years to be Nakamoto, but the judge ruled that he had lied extensively to support the claim.

Which cryptographer proposed 'bit gold', a forerunner of bitcoin, years before Nakamoto's white paper?

Nick Szabo is often named as a Nakamoto candidate, but he has repeatedly denied being bitcoin's creator.

Which 1997 Adam Back anti-spam scheme became a direct precursor of bitcoin mining?

Adam Back's Hashcash made each email cost a little computing time, trivial for one sender but costly for spammers, and bitcoin mining runs on the same idea.

Which bitcoin-based dark-web market did the FBI shut down in October 2013?

Silk Road's founder, Ross Ulbricht, was arrested by the FBI in a San Francisco public library.

What sentence did Ross Ulbricht receive in 2015 for running the dark-web market he founded?

Two life terms, no parole, plus 40 years was Ross Ulbricht's 2015 sentence, but President Trump pardoned him in January 2025.

Mt Gox, which collapsed in 2014, was first planned as a site for trading which game's cards?

Jed McCaleb bought the Mt Gox domain for a Magic: The Gathering card-trading site, then in 2010 turned it into a bitcoin exchange and sold it the next year.

What brought down Mt Gox, the Tokyo bitcoin exchange that collapsed in 2014?

Hackers stole its bitcoins, and after Mt Gox halted withdrawals, protesters turned up outside its Tokyo offices.

Which country became the first to make bitcoin legal tender, in September 2021?

El Salvador paid people to sign up for its Chivo bitcoin wallet, yet usage stayed low and kept falling.

Which country made bitcoin legal tender alongside the CFA franc in April 2022?

The Central African Republic did so although few of its people could get online, and using any cryptocurrency needs the internet.

Which famous investor called bitcoin 'probably rat poison squared' in 2018?

Warren Buffett said so, yet he also said he would never short it.

Which social network's celebrity accounts, including Barack Obama's, were hijacked in July 2020 to push a bitcoin scam?

Twitter's hijackers tricked staff into giving them access to internal admin tools, then posted tweets promising to double any bitcoin sent.

Which SEC chair approved the first US spot bitcoin ETFs?

Gary Gensler approved them after an appeals court ruled that the SEC had not adequately explained rejecting Grayscale's bitcoin fund.

Which company put $250 million of its treasury into bitcoin in August 2020?

MicroStrategy started out selling business software, but its bitcoin buying turned its shares into a stand-in for bitcoin itself.

Which bitcoin slang term began as a forum typo in December 2013?

'Hodl' began as a typo of 'hold' in a Bitcointalk post titled 'I AM HODLING' on 18 December 2013, written during a price crash; it came to mean holding through volatility.

Where is James Howells' lost bitcoin hard drive believed to be?

A Newport landfill is where it ended up in 2013, and in 2025 a High Court judge threw out his legal claim against the council, saying it had no realistic prospect of success.

Which university's researchers estimated in 2025 that bitcoin mining uses about 0.5% of the world's electricity?

Cambridge's researchers found mining's electricity use still growing even though mining machines had become more efficient.

Which mining pool alarmed the community in 2014 by reaching 51% of the network's hashing power?

Ghash.io then promised to keep its share below 40%, because a pool with a majority of the hashing power could double-spend coins.

Why does BTC not conform to the ISO 4217 currency standard?

BT is Bhutan's country code, and under ISO 4217 a code's first two letters name a country; units with no country, like gold's XAU, start with X.

Which Austrian-school economist's The Denationalisation of Money is cited by the ECB as a root of bitcoin?

Friedrich Hayek argued in that 1976 book that governments should not hold a monopoly on issuing money and that private currencies should compete.

Which economist described bitcoin as a Ponzi scheme in 2014?

Nouriel Roubini said so in 2014, but legal scholar Eric Posner argued that a real Ponzi scheme takes fraud, calling bitcoin 'more like a collective delusion'.

In March 2025 President Trump signed an executive order establishing what?

A strategic bitcoin reserve, stocked with bitcoin the government had already seized in forfeiture cases, which the order says will not be sold.

Which US agency's 2013 guidance classed virtual-currency exchangers as money transmitters?

FinCEN's March 2013 guidance brought exchangers and administrators under the Bank Secrecy Act, so they had to follow anti-money-laundering rules.

Which US fuel pipeline's operator took its system offline and paid a bitcoin ransom after a 2021 hack?

Colonial Pipeline paid the DarkSide hackers, and the Justice Department later seized back about $2.3 million of the bitcoin.

Which Finnish developer did Nakamoto task with creating content for the bitcoin.org website?

Martti Malmi also founded the Bitcointalk forum while helping Nakamoto develop the software.

Which second-layer network routes bitcoin payments through off-chain channels?

The Lightning Network settles payments in under a minute, sometimes in milliseconds, without waiting for a new block to be mined.

Once the last bitcoin is mined, around 2140, what will miners earn for adding blocks?

Transaction fees are meant to give miners a reason to keep mining once no new coins are being created.

Which country led global bitcoin mining after China's 2021 ban pushed miners abroad?

The United States took the lead, and in Texas, where many miners moved, their growing power demand raised worries about keeping the grid reliable.

To whom did Nakamoto hand the network alert key and control of the code repository before vanishing?

Gavin Andresen had built The Bitcoin Faucet, a site that gave away free bitcoins to newcomers, before Nakamoto handed him the project's lead.

Which soft-fork upgrade, activated in November 2021, added Schnorr signatures to Bitcoin?

Taproot lets a coin keep complex spending rules hidden unless they are actually used, making such payments cheaper and more private.

On which holiday in 2008 did Nakamoto post the bitcoin white paper to a cryptography mailing list?

Halloween was the day, 31 October 2008; the domain bitcoin.org had been quietly registered that August.

Under which alias from The Princess Bride did Ross Ulbricht run his bitcoin-only dark-web market?

Dread Pirate Roberts was the username, and whether Ulbricht was the only person ever to use the account remains disputed.

Programmer Stefan Thomas forgot the password to what kind of device, stranding about 7,000 bitcoins?

An encrypted USB stick made by IronKey holds the coins, and in 2023 a firm called Unciphered said it had found a way to unlock similar drives.

A bug exploited in August 2010 briefly created roughly how many bitcoins, far beyond the hard cap?

184 billion coins appeared in a single transaction, and a patched client that rejected it was published within five hours.

Which pair, who once sued Facebook's founder, owned about 1% of all bitcoins by 2013?

Cameron and Tyler Winklevoss began buying when a coin cost single digits, and in 2014 they founded the Gemini exchange in New York.

Which site began taking bitcoin donations in 2011 because no bank or government could block them?

WikiLeaks did well from the choice: by October 2017 Julian Assange was claiming a 50,000% return on its bitcoin.

In which city did the world's first bitcoin ATM open in October 2013, inside a downtown coffee shop?

Vancouver got the machine from two firms, Robocoin and Bitcoiniacs, and it let customers swap paper money for bitcoin or sell their coins on the spot.

Which plumbing word names a website that gives away free bitcoin, as one did in 2010 at five coins per visitor?

A faucet drips out tiny rewards for solving a captcha or a small task, though that first one's five coins per person would later be worth a fortune.

Which eurozone country's banking crisis is credited with helping fuel bitcoin's surge in spring 2013?

Cyprus and the wider euro debt crisis are among the reasons given for a run-up to $266 in April 2013, which was followed by a plunge to about $50.

Which price did one bitcoin first reach in December 2024, a month after Donald Trump's election win?

$100,000 arrived weeks after the election, as the president-elect promised to make America the world's crypto capital.

Which exchange's sudden collapse in November 2022 sent bitcoin to its lowest price in two years?

FTX filed for bankruptcy that month, and the shock spread: the lender BlockFi followed it into Chapter 11 before November was out.

Which payments giant said in October 2020 that users could buy and sell bitcoin in their accounts?

PayPal customers could not at first move their coins in or out, only hold them inside the app.

Which US city's mayor, Francis Suarez, said in November 2021 he would take his next paycheck in bitcoin?

Miami was where Suarez became known as the Bitcoin mayor, and he floated letting residents pay their taxes in the currency too.

Which tech founder and bitcoin advocate renamed his payments company Square as Block in December 2021?

Jack Dorsey has spoken at bitcoin conferences such as The B Word, and is even among the people speculated to be Nakamoto.

Which asset manager's iShares fund, launched in January 2024, was the world's largest bitcoin fund by May?

BlackRock saw the fund, known by its ticker IBIT, become the first newly launched spot bitcoin ETF to hold $1 billion in assets, in its first week of trading.

Which Wall Street bank chief called bitcoin a 'fraud' in 2017 and said he would fire staff who traded it?

Jamie Dimon, the head of JPMorgan Chase, compared the currency to a pyramid scheme, then later said he regretted the remark.

Which country's largest crypto exchange, QuadrigaCX, collapsed in 2019 after its founder died in India?

Canada lost its biggest exchange owing about C$215 million, and founder Gerald Cotten had signed his will just twelve days before he died.

What name is given to keeping bitcoin private keys offline, on a hardware device or a paper printout?

Cold storage guards against the thefts that hit online services, which keep customers' credentials on their own servers.

Which cryptocurrency did Google employee Charlie Lee release in 2011, building it from bitcoin's own codebase?

Litecoin caps its supply at 84 million coins, and its mining uses a function called scrypt that was designed to be costly to speed up with custom chips.

How does the title of Nakamoto's 2008 white paper describe the electronic payment system it proposes?

Peer-to-peer is in the title, yet the paper itself was never peer-reviewed, and academics at first ignored it, arguing the scheme could not work.

Which broadcaster's 2024 film Money Electric named developer Peter Todd as Nakamoto, which he denied?

HBO aired Cullen Hoback's film, and Todd called its theory ludicrous, likening it to coincidence-based conspiracy thinking.

Which programmer co-founded Bitcoin Magazine in 2011 and wrote for it before going on to create Ethereum?

Vitalik Buterin was approached about the magazine by Mihai Alisie in September 2011, and it has been called the first serious publication devoted to cryptocurrencies.

How did a 2014 IRS notice say bitcoin should be treated for US federal tax purposes?

As property, not currency, bitcoin falls under the same tax principles that apply to other property transactions.

Which flaw of electronic money did Nakamoto's white paper claim to solve without a trusted third party?

Double-spending, paying the same coin to two people, is usually prevented by a trusted middleman that checks whether a token has been spent.

What is the number bitcoin miners keep changing until a block's hash falls below the difficulty target?

Nonce hunting is pure trial and error, which is why mining demands so much computing power and specialised hardware.

Roughly how often does bitcoin recalibrate its mining difficulty, an adjustment made after 2,016 blocks?

Two weeks is the target, and the adjustment keeps the gap between blocks steady however many miners join or leave.

Which type of purpose-built chip overtook graphics cards to become the main way of mining bitcoin?

ASIC stands for application-specific integrated circuit: the chips do nothing but mine, and their arrival made mining on graphics cards unprofitable.

What is the waiting area called where unconfirmed bitcoin transactions sit until a miner puts them in a block?

Mempool is short for memory pool, and there is no single one: each node keeps its own slightly different set of waiting transactions.

Which word was added to the name of Nakamoto's original Bitcoin software to distinguish it from the network?

Core is the client regarded as bitcoin's reference implementation, and rival versions such as Bitcoin Unlimited began as forks of it.

Which privacy movement, named at a San Francisco Bay Area meeting, first proposed bitcoin-like money?

Cypherpunks got their name as a joke from Jude Milhon, who blended cipher with cyberpunk, and their mailing list had 700 subscribers by 1994.

Which thought experiment about commanders who cannot all be trusted is bitcoin mining said to overcome?

Byzantine generals problem is the classic picture of a system whose members must agree on a strategy though some are unreliable, as bitcoin's scattered miners must.

Which European capital installed a bust honouring bitcoin's unknown creator Nakamoto in 2021?

Budapest put up its tribute a decade after Nakamoto fell silent, having told a fellow developer in a 2011 email that he had moved on to other things.

Which early bitcoin promoter was nicknamed 'Bitcoin Jesus' for his evangelism in the currency's first years?

Roger Ver gave up his American citizenship in 2014, after becoming a citizen of Saint Kitts and Nevis.

Which venture capitalist bought nearly 30,000 seized bitcoins at a 2014 US Marshals auction?

Tim Draper paid about $19 million, and that September he predicted one bitcoin would reach $10,000 within three years.

Which exchange lost nearly 120,000 bitcoins in a 2016 breach that led to a New York couple's arrest in 2022?

Bitfinex saw about 94,000 of the coins seized by the US Justice Department in 2022, by which point that haul was worth more than $3 billion.

Which firm beat the SEC in court in August 2023 after it refused to let a bitcoin trust become an ETF?

Grayscale won by a unanimous vote of the appeals court in Washington, having argued that the regulator already allowed bitcoin futures ETFs.

Which ex-Soviet nation held about 18% of bitcoin mining by August 2021, after China banned the industry?

Kazakhstan took in miners leaving China, and because its power plants burn hard coal, the move pushed up bitcoin's carbon footprint.

Which US online retailer became the first major one to accept bitcoin as payment, in January 2014?

Overstock took more than 800 bitcoin orders worth $126,000 in the first 22 hours, though two months later they made up under 1% of its daily takings.

Which CBS legal drama made bitcoin the subject of a fictional trial in its 2012 episode 'Bitcoin for Dummies'?

The Good Wife aired the episode in January 2012, in its third season, less than two years after the first known purchase made with bitcoin.

Which Swiss city is nicknamed 'Crypto Valley' for its many cryptocurrency firms, among them Bitcoin Suisse?

Zug's canton has taken tax payments in bitcoin since 2021, and a Crypto Valley Association had formed there by 2018.

Which US agency made the first reported government seizure of bitcoin in June 2013, taking about 11 coins?

The DEA took the coins from a person trying to buy illegal drugs, months before the far larger FBI haul that October.

On which project-hosting site did Nakamoto release version 0.1 of the bitcoin software in January 2009?

SourceForge hosted the first client, which Nakamoto said he had begun coding in the second quarter of 2007, well before the white paper.

Which sanctioned country began in 2020 to make local bitcoin miners sell their coins to its monetary authorities?

Iran at first opposed cryptocurrencies, then began using them to get around sanctions, with the mined bitcoin paying for imports.

Which company, co-founded by Jihan Wu in 2013, makes the Antminer line of bitcoin mining machines?

Bitmain began with the Antminer S1, and a boardroom feud burst into view in 2019 when Wu announced his co-founder's removal.

Which computer engineer's 1998 proposal, b-money, was referenced in Nakamoto's bitcoin white paper?

Wei Dai was one of the first two people Nakamoto contacted while developing bitcoin in 2008, though he believes Nakamoto reinvented the idea without having read his article.

Which electronic money firm, founded by David Chaum in 1989, went bankrupt a decade before bitcoin appeared?

DigiCash built on Chaum's blind signature technology, designed so that not even the bank issuing the money could trace what an online shopper paid for.

Which boss of Mt Gox was arrested in 2015 and later convicted of falsifying the exchange's records?

Mark Karpelès received a 30-month sentence, suspended for four years, after prosecutors had pushed for ten years on charges including embezzlement.

Which data structure, patented in 1979, condenses all the transactions in a bitcoin block into a single hash?

Merkle tree roots let a lightweight wallet confirm a payment using only block headers and one branch, and the idea is named after cryptographer Ralph Merkle.

Which Asian country passed a law in April 2017 accepting bitcoin as a legal method of payment?

Japan had already moved a year earlier, when its Cabinet recognised virtual currencies as having a function similar to real money.

Which signature algorithm, built on an elliptic curve, was the only one bitcoin used until a 2021 upgrade?

ECDSA runs on a curve named secp256k1 in bitcoin, letting an owner sign a payment with a private key that the network checks against the public one.