What happens at a halving
Some chains define a subsidy schedule in their rules. At preset block heights the subsidy is divided by two. Because it's code, it happens automatically and predictably — no vote or announcement is needed — and it steadily reduces the annual inflation of the coin.
Bitcoin and Litecoin
Bitcoin's subsidy halves every 210,000 blocks (about four years) toward a 21 million coin cap. Litecoin follows the same concept scaled for its faster blocks: it halves every 840,000 blocks — also about four years — toward a maximum supply of 84 million.
Coins without halvings
Dogecoin pays a fixed amount per block and has no scheduled halving, so its supply keeps growing at a steady absolute rate, though the *percentage* inflation declines over time.
Effects on miners
- A halving cuts the subsidy portion of revenue in half immediately
- Less efficient miners may become unprofitable, and some leave the network, which can lower hashrate until difficulty adjusts
- Fees and price movements can offset some or all of the cut, but neither is guaranteed
Planning around a halving
When evaluating hardware, don't assume today's reward lasts through the payback period. Model your break-even using the reward schedule and consider scenarios at lower prices.
Reading the schedule
Because halvings are tied to block height, you can predict roughly when the next one arrives by dividing the blocks remaining by the blocks produced per day. Block times drift slightly with hashrate, so the date moves by days or weeks rather than being fixed. Check the current block height in a block explorer instead of trusting a countdown from a third-party site.