If you hold meaningful Bitcoin, you’ve probably worried about the question: what happens to this if I’m hit by a bus? The standard answers all have problems.
Just give your heir the seed phrase — they lose it, or they spend it before you die, or you change your mind and they already know the keys.
Multisig with family members — your family doesn’t get Bitcoin. They lose their key. They lose interest. They have a falling out. Multisig is a coordination problem, and inheritance is the worst possible time for a coordination problem.
A custodial inheritance service — you’re back to “trust someone else with your Bitcoin,” which is the thing you specifically chose self-custody to avoid.
There’s a fourth answer that hasn’t gotten enough attention: pre-signed timelocked transactions. The mechanism has been in Bitcoin since 2013. It doesn’t require your heir to be technical, it doesn’t require a multisig coordinator, and it doesn’t require you to trust any company. It just requires the Bitcoin network to do what it’s been doing for 17 years.
The mechanic, briefly
Every Bitcoin transaction has a field called nLockTime. It specifies an absolute block height (or timestamp) before which the transaction is invalid — meaning the network’s nodes refuse to relay or include it.
You can sign a transaction today with nLockTime set to, say, block 1,200,000 (roughly 4 years from now, at ~10 minutes per block). That transaction is a real, fully-signed Bitcoin transaction. It just can’t be broadcast yet. You can email it to your heir, print it as a QR code, save it to a USB drive, store it in a safe deposit box, hand it to your lawyer — the network won’t accept it until the unlock block has been mined.
That’s the inheritance. You hand the future signed transaction to your heir. When the time comes (and you didn’t update or cancel the plan), they broadcast it. The funds settle on-chain in the next block.
What’s signed into the transaction
When you build the inheritance plan, you commit to four specific things:
- The inputs — which UTXOs (chunks of Bitcoin) you’re spending
- The output(s) — where the funds go (your heir’s address)
- The fee — paid to whoever mines the broadcasting block
- The locktime — the block height the network enforces before relaying
All four are baked in at signing time. They can’t be changed without re-signing, and re-signing requires your private keys, which only you have.
Why this is actually elegant
Compared to the alternatives:
Versus giving your heir the seed: they only get one specific transaction’s worth of access. They can’t drain your other wallets, they can’t move funds before the unlock block, they can’t lose the keys to your entire holdings. The blast radius of an heir betraying you is exactly bounded by the inheritance amount.
Versus multisig: no coordinator needed at unlock time. No “where’s my co-signer’s key” panic. Your heir gets a piece of data and broadcasts it. The network does the rest.
Versus a custodial service: the company doesn’t hold anything. If Bitheritance disappears tomorrow, the heir package still works — it’s a standard signed Bitcoin transaction. Paste the hex into Sparrow / Electrum / Bitcoin Core CLI and broadcast.
What you give up
Honest accounting of the trade-offs.
Fees are baked in at sign time
You decide the fee now, and the network requires it in N years. If mainnet fees spike during a future congestion event, an underpriced inheritance transaction may sit in mempool indefinitely. We recommend setting fees at the higher end (50+ sat/vB) plus an optional anchor output the heir can use to bump the fee at broadcast time via CPFP. Even with an anchor, mempool fluctuations are a real consideration for long-dated plans.
Spending any committed UTXO invalidates the plan
The inheritance transaction spends specific UTXOs. If you spend one of them in the meantime — paying a merchant, consolidating, sweeping to a new wallet — the network rejects your inheritance transaction as a double-spend. The plan is invalid until you rebuild it.
This is a feature (it’s the cancellation mechanism: spend any UTXO to cancel) and a footgun (you can accidentally cancel by not thinking about which coins are committed). The right mitigations: use a dedicated fresh wallet for inheritance, or pick cold UTXOs you don’t normally touch. We have a whole separate post on this.
Long horizons run into post-quantum risk
Bitcoin’s signature schemes (ECDSA, Schnorr) are vulnerable to sufficiently large quantum computers. The window when this becomes a real concern is “sometime in the 2030s” — estimates vary. A 30-year inheritance plan signed today is a long bet on the protocol situation staying favorable. Our wizard warns when your unlock block lands past 2030; for very long horizons, plan to re-sign every few years as the protocol evolves.
Recipient address can’t change
If your heir loses their wallet between signing and broadcast, the inheritance still goes to the address you committed. They need to be holding the keys to that address when the time comes. (Pre-arranged addresses on a hardware wallet they own works. Hot wallets they later abandon don’t.)
Where Bitheritance fits
We’re the tool that makes building this transaction tractable. The actual cryptography is your wallet’s job — Sparrow, Coldcard, Ledger, Trezor, whatever you already use. We give you a wizard that says “here’s the recipient, here’s the locktime block, here’s the fee rate, copy these into your wallet’s Send tab,” and then we wrap the resulting signed hex into a portable package (QR + JSON + share link + printable PDF) you can hand to your heir.
We also optionally watch the chain on your behalf and send email alerts when something changes — invalidation, approaching unlock, broadcast, confirmation. That’s a paid feature ($2/month, mainnet only) because polling the chain for years is the only thing that has real ongoing operational cost. Building the plan is free.
The architecture matters: we don’t custody anything. Your keys never touch our server. The signed transaction lives in your wallet (and in copies you save). If we shut down, the package still works. If we get hacked, the worst case is the attacker reads xpubs you opted to save — they can derive your addresses but can’t spend.
Try it on signet first
Signet is Bitcoin’s test network — same protocol, no real-value coins, free faucet to get test BTC. Build a plan with a short unlock block (10 blocks ahead), wait the ~100 minutes for it to fire, broadcast it as the “heir,” and you’ve end-to-end tested the whole flow before risking real money on mainnet.
The free-tier in Bitheritance covers signet completely. We strongly recommend doing this once before building anything for real.
If you’ve thought about Bitcoin inheritance and bounced off the available options, this approach is worth understanding. It’s not magic — every trade-off above is real — but the structure is honest in a way the custodial alternatives aren’t. The network enforces the timelock, not us. That changes everything about what trust means here.