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Polkadot Parameters

Many of these parameter values can be updated via on-chain governance. If you require absolute certainty of these parameter values, it is recommended you directly check the constants by looking at the chain state and/or storage.

Periods of common actions and attributes

NOTE: Polkadot generally runs at ¼th the speed of Kusama, except in the time slot duration itself. See Kusama Parameters for more details on how Polkadot's parameters differ from Kusama's.

  • Slot: 6 seconds *(generally one block per slot, although see note below)
  • Epoch: 4 hours (2_400 slots x 6 seconds)
  • Session: 4 hours (Session and Epoch lengths are the same)
  • Era: 24 hours (6 sessions per Era, 2_400 slots x 6 epochs x 6 seconds)
PolkadotTimeSlots*
Slot6 seconds1
Epoch4 hours2_400
Session4 hours2_400
Era24 hours14_400

*A maximum of one block per slot can be in a canonical chain. Occasionally, a slot will be without a block in the chain. Thus, the times given are estimates. See Consensus for more details.

Governance

DemocracyTimeSlotsDescription
Voting period28 days403_200How long the public can vote on a referendum.
Launch period28 days403_200How long the public can select which proposal to hold a referendum on, i.e., every week, the highest-weighted proposal will be selected to have a referendum.
Enactment period28 days403_200Time it takes for a successful referendum to be implemented on the network.
CouncilTimeSlotsDescription
Term duration7 days100_800The length of a council member's term until the next election round.
Voting period7 days100_800The council's voting period for motions.

The Polkadot Council consists of up to 13 members and up to 20 runners up.

Technical committeeTimeSlotsDescription
Cool-off period7 days100_800The time a veto from the technical committee lasts before the proposal can be submitted again.
Emergency voting period3 hours1_800The voting period after the technical committee expedites voting.

Staking, Validating, and Nominating

Motion #108 proposed new nomination limits to the Polkadot network, offering a temporary solution to increase the stability and security of the network. Note that this motion does not increase the maximum nominator count (22_500). This motion got enacted as a referendum and the value of the minimum nominator bond is updated from 80 DOTs to 120 DOTs. As most of these parameters can be updated via on-chain governance, please check the latest parameters on chain state (selected state query -> staking -> minimumNominatorBond and maxNominatorsCount)

PolkadotTimeSlotsDescription
Term duration1 Day14_400The time for which a validator is in the set after being elected. Note, this duration can be shortened in the case that a validator misbehaves.
Nomination period1 Day14_400How often a new validator set is elected according to Phragmén's method.
Bonding duration28 days403_200How long until your funds will be transferrable after unbonding. Note that the bonding duration is defined in eras, not directly by slots.
Slash defer duration28 days403_200Prevents overslashing and validators "escaping" and getting their nominators slashed with no repercussions to themselves. Note that the bonding duration is defined in eras, not directly by slots.

Treasury

TreasuryTimeSlotsDescription
Periods between spends24 days345_600When the treasury can spend again after spending previously.

Burn percentage is currently 1.00%.

Precision

DOT have 10 decimals of precision. In other words, 10 ** 10 (10_000_000_000 or ten billion) Plancks make up a DOT.

The denomination of DOT was changed from 12 decimals of precision at block #1248_328 in an event known as _Denomination Day. See Redenomination for details.