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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#

As of June 30, 2021, the staking parameters have been modified to a minimum of 40 DOT to nominate, and a maximum of 22_500 total nominators. 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.