Networks produce blocks at intervals ranging from a fraction of a second to several minutes. These figures are not properties of the technology; they are deliberate settings with predictable consequences.
Propagation sets the floor
A newly produced block must reach the rest of the network before the next one is built, and that takes time proportional to block size and network diameter.
If blocks are produced faster than they propagate, participants routinely build on stale information, creating competing branches that must later be discarded.
The safe interval is therefore tied to how quickly the network can distribute a block, which depends on bandwidth, node geography and the efficiency of the relay protocol.
Short intervals waste work and complicate consensus
When two valid blocks appear at nearly the same height, only one can survive. The effort behind the other is discarded.
Frequent orphaning weakens security, because attacking effort is compared against the effort that actually contributes to the chain rather than the total expended.
It also advantages well-connected participants, who hear about new blocks first and lose less work, which pushes the network towards centralisation among the best-connected operators.
Long intervals cost usability and add variance
Slow blocks mean users wait longer for a first confirmation, which is awkward for payments and for any application needing prompt feedback.
Where block production is probabilistic, the interval is an average rather than a schedule, so individual gaps vary considerably around it.
Longer intervals also concentrate transactions into fewer, larger blocks, which makes fee competition lumpier as everyone waiting competes for the same next slot.
Proof of stake changes the constraint
Where a scheduled validator produces each block, the network can use fixed slots rather than a random process, removing much of the timing variance.
The interval still cannot fall below what propagation and attestation require, since validators must see a block and vote on it before the next slot begins.
Networks targeting very short slots address this by demanding more of their validators in bandwidth and hardware, which is a deliberate trade of accessibility for speed.
The parameter shapes the ecosystem
Applications are built around the confirmation rhythm they expect, so changing the interval later affects everything from exchange deposit policies to contract design.
Slow chains push activity into layers above them, where interaction happens quickly and settlement happens on the base layer at its own pace.
Fast chains keep more activity on the base layer but ask more of anyone running a node, which shows up over time in how many independent participants can afford to verify the chain themselves.