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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.

  • 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.

Accounts, Identity and Crowdloans​

  • The Existential Deposit is
  • The deposit required to set an Identity is
  • The minimum contribution required to participate in a crowdloan is

Governance​

ParameterTimeSlotsDescription
Voting period28 days403_200How long the public can vote on a referendum.
Enactment period28 days403_200Time it takes for a successful referendum to be implemented on the network.

Staking, Validating, and Nominating​

The maximum number of validators that can be nominated by a nominator is 16.

ParameterTimeSlotsDescription
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.

Parachains​

Crowdloans and AuctionsTimeSlotsDescription
Auction duration7 days100_800The total duration of the slot auction, subject to the candle auction mechanism.
Opening period2 days28_800The opening period of the slot auction.
Ending period5 days72_000The ending period of the slot auction.
Parachain SlotTimeSlotsDescription
Lease period12 weeks1_209_600The length of one lease period in a parachain slot.
Total slot duration2 years10_512_000The maximum duration a parachain can lease by winning a slot auction (8 lease periods).

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 #1,248,328 in an event known as Denomination Day. See Redenomination for details.