Found a block solo: what happens next, all the way to taxes

When your machine finds a block, the pool A server that machines connect to. A regular pool shares the earnings, a solo pool does not. Solo or pool? has already prepared its coinbase The first transaction of a block, the one that pays the reward. On a solo pool it pays your address directly. transaction: the very first transaction of the block, the one that creates the new bitcoin and sends it to your address. Your wallet shows it almost at once, but you cannot move it: the send button stays greyed out, or the network rejects the transaction.

It is a rule written into Bitcoin’s code, maturity The wait before freshly mined bitcoin can be spent: 100 blocks after its own, about 16 hours 40 minutes.: freshly mined bitcoin cannot be spent until 100 new blocks have been added after yours. At one block every ten minutes on average, that is about 16 hours 40 minutes. Meanwhile, some wallets show these coins as “immature”.

This rule prevents a disaster. Sometimes two miners find a block almost at the same moment, at opposite ends of the world. The network can only keep one: it follows the branch the next block is built on, and the other becomes an orphan block A valid block the network sets aside because another block found at the same moment won. Its reward disappears with it. Found a block: what happens next. This is called a reorganisation. If the block set aside was yours, its coinbase transaction disappears with it, and so does your bitcoin.

The 100 blocks of maturity leave plenty of time for such cases to settle before the coins can move. Until they have passed, keep the champagne on ice.

Check today the Bitcoin address set in your machine: in AxeOS The open-source Bitaxe software, set from a browser: pool, frequency, voltage, fan. Update it, it is the start of the User field, before the dot. Many beginners put the deposit address of their exchange account there, to save time. Never do that.

A coinbase transaction has no sender: these are brand-new coins that come from no address. Some exchanges cannot credit this kind of deposit automatically, or set it aside for review. And since you do not hold the keys to that address, you depend entirely on their support team to prove the block is yours, sometimes for weeks. An exchange can also change or close a deposit address.

When mining solo, always mine to a wallet whose keys you hold: a hardware wallet A small device that holds the keys and signs transactions without ever showing them to the computer. Always check on its screen what you approve., or software such as Sparrow Wallet. Once the 100 blocks have passed, the coins are yours, with no middleman (which wallet to choose). On FindMyBlock, the reward goes straight to that address: the pool never holds it.

The 100 blocks have passed, your bitcoin is available, and you decide to sell part of it. Send that kind of amount in one go to a regulated exchange in Europe (licensed under MiCA, the EU framework that replaced France’s PSAN status) and a compliance alert is very likely to go off. This is the fight against money laundering, known as KYC and AML.

The exchange can then block your euro withdrawal and ask for the source of funds. Yet you have no payslip for this gain and no card purchase history: you mined these coins.

Get these documents ready before you send anything: they make the release much faster.

1. The block link on an explorer such as mempool.space: it shows the coinbase transaction paying your address.
2. A signed message, made with the private key The secret that proves some bitcoin belongs to you and lets you spend it. Your wallet keeps it; the recovery phrase can rebuild it. of the address that received the block. Your wallet signs a short text, for example “This address belongs to me” and the date; anyone can check the signature, and it proves mathematically that you hold that address. In Sparrow Wallet, it is the Tools menu, then Sign/Verify Message, for bc1q addresses, the most common kind.
3. Your miner’s purchase invoice, a Bitaxe or a NerdQAxe, and a screenshot of your pool dashboard, on FindMyBlock or Public Pool for example, showing the block found.

Now for the touchy subject. These are the rules in France, where I live. Many people think that as long as the coins stay in their wallet, never converted to euros, they owe nothing, and that when they sell they will simply pay the flat tax: 31.4% since 2026, 30% before. For mining, that is not the rule.

For the French tax administration, mining gains are non-commercial profits (BNC, for bénéfices non commerciaux). The tax arises when you receive the bitcoin: you have earned an income equal to its value in euros on the day the block was mined, even if you sell nothing.

These are French rules as they read in October 2026, and I am neither a lawyer nor an accountant: with a block at stake, get professional advice. Elsewhere the rules differ: in the United States, for example, mined coins are also income as soon as you receive them; in other countries, check with your tax authority.

In France, this income is declared under one of two regimes:

Micro-BNC applies as long as your receipts of the previous year or the year before do not exceed a ceiling: €83,600 for 2026 to 2028 (€77,700 before). A block, about €220,000, exceeds it on its own, but the regime does not switch that same year: real expenses only become compulsory after two years in a row above the ceiling. You can also opt for them.

For a small miner, whose real expenses are low, the 34% allowance is often the better deal. Either way, this income is added to your household’s: it is taxed at the progressive income tax rates, plus social charges. And if you use a foreign exchange, report that account every year too (form 3916-bis).

This is the real trap. You find a block when it is worth about €220,000, you sell nothing, and bitcoin loses half its value the following year: you still owe the tax calculated on its value the day you mined it.

Hence reflex number one: as soon as the coins are available, convert right away enough to pay the tax, to shelter that share An attempt good enough to be counted by the pool. It proves your machine is working, even if it is not enough to find a block. from market swings. Keep a dated record of the block’s value when you received it, with the block link and the price at that moment: it is the basis of your tax return.

And tell your bank adviser before the exchange’s transfer lands in your current account: a transfer that size, unexplained, can trigger a freeze too.

Finding a block solo is every home miner’s dream, and Bitaxe units have already done it: blocks found solo. But a €220,000 dream is prepared before it comes true: check now that your machine mines to a wallet whose keys you hold (the AxeOS setting), and keep your miner’s invoice within reach.

And you: if your Bitaxe found a block tonight, would you keep your 3.125 BTC, or sell right away? Say so under the video or on Discord. To mine solo, FindMyBlock, my pool: the reward goes straight to your address.