The Bitcoin Halving Explained: Impact on Mining

TL;DR. Every ~4 years, the Bitcoin block reward is cut in half. Four halvings since 2009 (50 → 25 → 12.5 → 6.25 → 3.125 BTC). The next is expected spring 2028 (1.5625 BTC). For miners, each halving forces inefficient hardware offline and compresses hashprice. Modeling post-halving 2028 is mandatory for any 2026 ASIC purchase.

The halving in 30 seconds

Every 210,000 blocks (~4 years at 10-minute target block time), the miner's reward is cut in half. Hard-coded in the protocol, immutable without a hardfork the entire network accepts.

Why the halving exists

Satoshi Nakamoto designed Bitcoin with a fixed money supply: never more than 21 million BTC. The halving progressively slows new issuance to respect that cap.

BTC annual inflation is also halved at each event:

Period	Annual BTC inflation
2020-2024 (6.25 reward)	~1.8%
2024-2028 (3.125 reward)	~0.8%
2028-2032 (1.5625 reward)	~0.4%

Compare with fiat currency inflation: 2-8%/year typical for major currencies.

History: 4 halvings since 2009

Halving	Date	Reward	Hashrate before	BTC price
#1	Nov 2012	50 → 25 BTC	~25 TH/s	~$12
#2	Jul 2016	25 → 12.5 BTC	~1.5 EH/s	~$650
#3	May 2020	12.5 → 6.25 BTC	~120 EH/s	~$9,000
#4	Apr 2024	6.25 → 3.125 BTC	~620 EH/s	~$64,000

Historical pattern: BTC price rose meaningfully in the 12-18 months following each halving. No guarantee this repeats — past correlation isn't a promise.

Concrete impact on mining

1. Revenue / 2 overnight

At the exact halving moment, miner BTC revenue is cut in half at constant hashrate. If your ASIC produced 0.001 BTC/month the day before, 0.0005 BTC/month the day after.

The only catch-up = compensating BTC price increase. Historically that happened. No certainty going forward.

2. Capitulation of inefficient miners

Miners with high J/TH (old machines, S19 = ~30 J/TH) become immediately cash-negative post-halving. They unplug.

Cascade effect:

• Global hashrate drops
• Difficulty adjusts downward next epoch
• Efficient miners (low J/TH) become even more profitable

It's the network's Darwinian self-regulation.

3. Durable hashprice compression

The hashprice (USD/TH/day revenue) mechanically halves at the event, then partially recovers via difficulty adjustment. But stays structurally lower than pre-halving for 6-12 months.

This is what eliminates marginal miners and concentrates profitability on efficient operators.

The next halving: spring 2028

At 10 minutes per block and 210,000 blocks between halvings, block 1,050,000 (triggering the 5th cut) is expected late April to mid-May 2028.

Post-halving 2028 reward: 3.125 → 1.5625 BTC per block.

Implications for 2026 buyers

If you buy an ASIC in 2026 and plan a 24-month amortization, your model MUST incorporate the 2028 halving.

At constant 2026 hashprice, your BTC revenue halves the day of the halving — unless BTC price compensates.

Practical implication:

• Pick an ASIC at J/TH < 12 (S23 Hydro 3U at 9.5, S21 XP Hyd at 12)
• Electricity cost below $0.07/kWh (so professional hosting basically required)
• Model post-halving break-even before purchase, not after

What to do as a miner

Three levers:

1. Optimize J/TH

Refresh hardware every 3-4 years. S19s (2022, ~30 J/TH) are at break-even in 2026. S21s (15 J/TH) will hold through 2028. S23s (9.5 J/TH) will hold past.

2. Cut kWh

Going from $0.18 (US residential) to $0.07 (hosting) doubles your margin. On an S21 Pro, that's ~$2,600/year on a single machine.

3. Model post-halving before buying

Calculate break-even with:

• Future reward 1.5625 BTC (instead of 3.125)
• Global hashrate +30% vs today (conservative)
• BTC price unchanged

See ASIC miner ROI calculator guide.

Further reading

• Is bitcoin mining profitable in 2026?
• Bitcoin mining electricity cost
• Hosted bitcoin mining

The Bitcoin Bay is an introducer. Any 2028 projection is conditional on assumptions that may shift. Mining involves capital loss risk.