Technical › Network

Emission, blocks and fees

Tail emission, dynamic block size and the penalty for big blocks

In short

The block reward decreased smoothly until May 2022 and is now forever 0.6 XMR per block (tail emission). There's no hard block size limit: it grows with demand, but a miner who makes a block larger than the median loses part of the reward.

The emission curve

reward = max( 0.6, (M − A) · 2⁻¹⁹ · 10⁻¹² ) M = 2⁶⁴ − 1 atomic units, A — already emitted; 2⁻¹⁹ is for 2-minute blocks

The reward decreases smoothly every block rather than in steps (like Bitcoin's halvings). About 18.132 million XMR were emitted by the main curve, after which the reward became constant.

Total XMR supply (orange) and block reward (teal). Computed from the formula above, simplified as if blocks had always been 2 minutes (until 2016 they were 1 minute, with a corresponding 2⁻²⁰ shift).

Why tail emission

  • Security: miners must always be paid. If the reward is fees only, security depends on whether users are willing to pay high fees.
  • Lost coins: some coins are lost every year; constant emission roughly compensates, and circulating supply stabilises.
  • Inflation decreases: 0.6 XMR × 262,800 blocks per year ≈ 157,680 XMR per year — under 1%, and falling in percentage terms every year.

Dynamic block size

Instead of a fixed limit Monero uses the median weight of recent blocks:

  • short-term median — over the last 100 blocks;
  • long-term median — over the last 100,000 blocks (limits growth);
  • minimum — 300,000 bytes of weight.

A block can be up to 2× the median, but if it's above the median the miner pays a penalty — part of the base reward is burned:

penalty = reward · ( weight / median − 1 )²

A miner includes extra transactions only if their fees exceed the penalty. So block growth is automatically tied to what users are willing to pay, and fees stay low under normal load.