How the countdown works
On load, the tool estimates the current block height from the 4th halving (block 840,000 on 20 April 2024) and a ten-minute average. That is only a starting point — real blocks have recently been a little faster than ten minutes on average, so the estimate drifts. Type the actual height from a block explorer, or press “Load live height” to fetch it from mempool.space (a single request from your browser, made only when you click).
From the height, the calculator works out the blocks remaining until the next multiple of 210,000, multiplies them by the average block time and adds the result to the current time. Change the block time to 9.5 or 10.5 minutes to see a realistic range for the date.
next halving block = (⌊height / 210,000⌋ + 1) × 210,000
blocks left = next halving block − height
estimated date = now + blocks left × average block time
block subsidy = 50 BTC / 2^⌊height / 210,000⌋Bitcoin halving history
Each halving so far, with the subsidy that applied after it:
- 1st halving — block 210,000, 28 November 2012: 50 → 25 BTC.
- 2nd halving — block 420,000, 9 July 2016: 25 → 12.5 BTC.
- 3rd halving — block 630,000, 11 May 2020: 12.5 → 6.25 BTC.
- 4th halving — block 840,000, 20 April 2024: 6.25 → 3.125 BTC.
- 5th halving — block 1,050,000, expected in 2028: 3.125 → 1.5625 BTC.
Why the halving matters
The subsidy is how new bitcoins enter circulation, so each halving cuts the rate of new supply in half. It also cuts miners' revenue from the subsidy, leaving transaction fees as a growing share of their income. The schedule is fixed by the protocol: the total supply approaches but never exceeds 21 million BTC, with the last fraction of a bitcoin expected to be mined around the year 2140. More than 95% of all bitcoins have already been issued — the tool shows the exact figure for the height you enter.
Past halvings have been followed by large price moves, but every cycle happened in a different market, and an event everyone can see coming is not a reliable trading signal. Treat the countdown as a calendar, not a forecast.
Why the date keeps moving
Bitcoin targets a ten-minute block interval by adjusting mining difficulty every 2,016 blocks (about two weeks). When hash rate grows faster than difficulty adjusts, blocks come a little faster and the halving moves earlier; when miners switch off, it moves later. That is why estimates published months in advance can be off by weeks — the block height is exact, the date is not.
- Use the block height, not the date, when you need a precise reference.
- Re-check the estimate closer to the event; the remaining uncertainty shrinks as fewer blocks are left.
- The subsidy changes at the first block of the new epoch — block 1,050,000 itself pays 1.5625 BTC.
What changes for users on halving day
For people who hold or send bitcoin, nothing changes technically: addresses, wallets and balances keep working, and no action is required. Miners' revenue per block falls, and around past halvings some less efficient miners switched off, which briefly slowed blocks until difficulty adjusted. Fees can be volatile around the event because of extra on-chain activity, so if you need to move coins that week, check the current fee rate before sending.
Scammers like big dates. Messages promising to “double your bitcoin for the halving” or asking you to “migrate” your wallet are always fraudulent — the halving needs nothing from you.
Frequently asked questions
+When is the next Bitcoin halving?
At block 1,050,000, expected in 2028. The countdown above estimates the date from the current block height and an average block time you can adjust.
+What will the block reward be after the next halving?
It drops from 3.125 BTC to 1.5625 BTC per block. Miners also keep transaction fees.
+How often does Bitcoin halve?
Every 210,000 blocks, which at ten minutes per block is about four years.
+How many halvings will there be?
The subsidy keeps halving until it rounds down to zero satoshis — after 33 halvings in total, around the year 2140.
+Where does the live block height come from?
Only when you click “Load live height”, your browser requests it from mempool.space. Otherwise the page uses an offline estimate you can override.
Calculations run entirely in your browser; nothing you type is sent to KOT.CASH. Results are estimates for information only and are not financial, tax or legal advice.