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.

Polkadot

• 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

Kusama

• Slot: 6 seconds *(generally one block per slot, although see note below)
• Epoch: 1 hour (600 slots x 6 seconds)
• Session: 1 hour (6 sessions per Era)
• Era: 6 hours (3600 slots x 6 seconds)

Kusama	Time	Slots*
Slot	6 seconds	1
Epoch	1 hour	600
Session	1 hour	600
Era	6 hours	3_600

*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

Polkadot

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

Kusama

Parameter	Time	Slots	Description
Voting period	7 days	100_800	How long the public can vote on a referendum.
Enactment period	8 days	115_200	Time 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 can be see here.

Polkadot

Parameter	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.

Kusama

Parameter	Time	Slots	Description
Term duration	6 hours	3_600	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	6 hours	3_600	How often a new validator set is elected according to Phragmén's method.
Bonding duration	7 days	604_800	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	7 days	604_800	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.

Treasury

Polkadot

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%.

Kusama

Treasury	Time	Slots	Description
Periods between spends	6 days	86_400	When the treasury can spend again after spending previously.

Burn percentage is currently 0.20%, though instead of being burned this amount is temporarily redirected into the Society's treasury to fund growth.

Precision

Polkadot

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.

Kusama

KSM have 12 decimals of precision. In other words, 1e12 (1_000_000_000_000, or one trillion) Plancks make up a single KSM.