I was trying to add a crowdloan campaign for Kusama auction. I went through all these videos https://www.youtube.com/playlist?list=PL5iFq6rVsyFa1WyBzKOSuntzTrxma-vba.

I am not able to decide:

  1. What should be ending block for my campaign?
  2. What should be First and Last period?

Can someone please help me to understand these parameters?

2 Answers 2


Lets take for example you wanted to launch a crowdloan were targeting lease period 21-28 on Kusama.

For your crowdloan settings:

  • index: Your Parachain ID
  • cap: The maximum number of tokens you want to accept.
  • first_period: The first lease period you want, in this case 21.
  • last_period: The last lease period you want, in this case 28.
  • end: The block number you want the crowdloan to end. This will either be aligned with the auction schedule, or at most, be the last block in lease period 21, since afterward, you can no longer win slot 21, and the crowdloan is invalid.

When selecting the end date for your crowdloan, you should first look at the auction schedule.

According to https://kusama.network/auctions/, the first auction for 21 - 28 will be the 31st auction:

Auction #31
- Auction Starts April 6th, 2022 - Block #12096600
- Bidding Ends April 13th, 2022 - Block #12195600
- Slot Duration Lease Period 21-28; May 19th, 2022 - April 27th, 2023

The last auction for 21 - 28 will be Auction #35:

Auction #35
- Auction Starts May 4th, 2022 - Block #12499800
- Bidding Ends May 11th, 2022 - Block #12598800
- Slot Duration Lease Period 21-28; May 19th, 2022 - April 27th, 2023

As you can see, bidding for this last auction ends on Block #12598800.

I would recommend to set your crowdloan end at that time.

  • 1
    I had a discussion with other Parity team member. Here is what he suggested I should check the dispatch polkadot.js.org/apps/?rpc=wss%3A%2F%2Fkusama-rpc.dwellir.com#/… under the id Auctlp21. The auctions will start on block #12,096,600, each will last 27,000 blocks and will start at intervals of #100,800 blocks. Therefore I should use as ending block of my crowdloan the first block of Period 21, which is 12,700,800. I have selected 12,700,800 as ending block for my crowdloan and Lease Period 21-28 Commented Apr 2, 2022 at 17:08

I did not watch the video, but the following information may help that shows the whole auction periods which consists of a grace period (or auction stage) and a candle phase (or ending stage) .

|starts|--27000 blocks (grace period ~ 2days)--|==72000 blocks (candle Phase ~ 5days)==|ends|

candle phase start block can be fetched via : api.query.auctions.auctionInfo();

and candle phase duration (ending period) via : api.consts.auctions?.endingPeriod

then the starts and ends of periods can be easily calculated.

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