Parameters

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)

Polkadot	Time	Slots*
Slot	6 seconds	1
Epoch	4 hours	2_400
Session	4 hours	2_400
Era	24 hours	14_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 1.000 DOT

• The deposit required to set an Identity is 20.258 DOT

• The minimum contribution required to participate in a crowdloan is 5.000 DOT

Governance​

Democracy	Time	Slots	Description
Voting period	28 days	403_200	How long the public can vote on a referendum.
Launch period	28 days	403_200	How 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 period	28 days	403_200	Time it takes for a successful referendum to be implemented on the network.

Council	Time	Slots	Description
Term duration	7 days	100_800	The length of a council member's term until the next election round.
Voting period	7 days	100_800	The council's voting period for motions.

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

Technical committee	Time	Slots	Description
Cool-off period	7 days	100_800	The time a veto from the technical committee lasts before the proposal can be submitted again.
Emergency voting period	3 hours	1_800	The voting period after the technical committee expedites voting.

Staking, Validating, and Nominating​

Maximum number of Validators that can be nominated by a nominator - 16

Polkadot	Time	Slots	Description
Term duration	1 Day	14_400	The 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 period	1 Day	14_400	How often a new validator set is elected according to Phragmén's method.
Bonding duration	28 days	403_200	How long until your funds will be transferrable after unbonding. Note that the bonding duration is defined in eras, not directly by slots.
Slash defer duration	28 days	403_200	Prevents 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 Auctions	Time	Slots	Description
Auction duration	7 days	100_800	The total duration of the slot auction, subject to the candle auction mechanism.
Opening period	2 days	28_800	The opening period of the slot auction.
Ending period	5 days	72_000	The ending period of the slot auction.

Parachain Slot	Time	Slots	Description
Lease period	12 weeks	1_209_600	The length of one lease period in a parachain slot.
Total slot duration	2 years	10_512_000	The maximum duration a parachain can lease by winning a slot auction (8 lease periods).

Treasury​

Treasury	Time	Slots	Description
Periods between spends	24 days	345_600	When 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.