Every Polkadot account must hold at least the existential deposit (ED) of the chain it lives on. If its balance falls below that line, the account is reaped: it is removed from the chain's state and the leftover amount is lost. On the Polkadot relay chain the ED is 1 DOT. On Polkadot Asset Hub, where everyday DOT balances and transfers are increasingly handled, the ED is lower — one tenth of the relay value, 0.1 DOT, in the runtime constants of the system parachains. Knowing which chain your DOT is on, and keeping a little above its ED, prevents almost every “my DOT disappeared” story.
Why Polkadot deletes small accounts
Substrate-based chains store each account as an entry in the state, and every node keeps that state. The existential deposit is the price of existing: an account must lock a minimum balance to occupy space. When the free balance drops below the ED — for example, because you sent almost everything away — the chain cleans up the entry. The remaining dust is removed with it. This is deliberate and documented; it is not a bug or a theft.
| Chain | Role | Existential deposit | Source |
|---|---|---|---|
| Polkadot relay chain | Consensus, historically balances and staking | 1 DOT | Polkadot Wiki |
| Polkadot Asset Hub | Balances, tokens (USDT, USDC), transfers | 0.1 DOT (system parachain constant) | polkadot-fellows runtimes |
| Other parachains | Their own tokens and rules | Set by each chain | Chain documentation |
Values are protocol constants and can change with a runtime upgrade; wallets such as Nova, Talisman and Polkadot.js show the current ED for the selected chain. Check there before moving the last part of a balance.
Asset Hub and the provider's DOT network
Polkadot Asset Hub (formerly called Statemint) is a system parachain designed for balances and assets. Polkadot has been moving everyday activity — DOT balances, transfers and the USDT and USDC issued on Polkadot — from the relay chain to Asset Hub. The liquidity provider behind KOT.CASH lists DOT on the network code STATEMINT, which is Asset Hub. Deposits are credited after 15 confirmations; Asset Hub produces blocks every few seconds, so that takes about a minute or two.
The address format is the same on both chains: Polkadot SS58 addresses with network prefix 0 start with “1”. The same address exists on the relay chain and on Asset Hub, but balances are separate per chain. A wallet showing 0 DOT on one chain may hold DOT on the other; switch the chain in the wallet's network list.
Situations that reap an account
- Sending almost the entire balance and leaving, say, 0.05 DOT on Asset Hub — below the ED, so the remainder is lost.
- Paying a fee that takes the free balance below the ED. Wallets usually warn, but scripts and some interfaces do not.
- Unstaking and transferring out in two steps where the second leaves a dust remainder.
- Receiving a tiny amount below the ED on a new account: the transfer fails because the account cannot be created.
Polkadot.js and most wallets have a “keep-alive” option on transfers that refuses to send if the account would be reaped. Leave it on unless you deliberately want to empty the account completely.
Locks, reserves and the ED
Your DOT balance on a Substrate chain has several parts: free, reserved (for example, deposits for on-chain identity or proxy accounts) and locked (staking, governance votes). Locked funds still count toward keeping the account alive, but they cannot be transferred. Unbonding staked DOT takes 28 days on Polkadot; the unbonding period lookup lists other networks. Reserved deposits come back when you clear the identity or remove the proxy.
Before you send DOT to a swap
- Check in your wallet whether the DOT is on Asset Hub or on the relay chain. The provider expects Asset Hub DOT; move it with the wallet's teleport function first if it is on the relay chain.
- Keep at least the ED plus a small fee reserve if you plan to keep using the account.
- Send the exact amount shown in the order, to the deposit address shown on the order page.
- If you want to empty the account, turn off keep-alive deliberately — the remainder after the fee is then simply not left behind.
On KOT.CASH you can swap DOT to USDT; the DOT to USDT guide walks through the order step by step. The payout network fee of the destination coin is included in the quote.
Tokens on Asset Hub and sufficiency
Asset Hub also holds tokens such as USDT and USDC issued on Polkadot. Each asset has its own minimum balance set when it was created. Some assets are marked “sufficient”, meaning an account holding only that asset may exist without any DOT; others are not, and the account must also hold DOT above the ED. Fees on Asset Hub can often be paid in sufficient assets such as USDT, but the safest habit is still to keep a small DOT balance alongside tokens.
FAQ
What is the existential deposit on Polkadot?
1 DOT on the relay chain; 0.1 DOT on Asset Hub according to the system parachain constants. Check your wallet for the current value.
What does “account reaped” mean?
The balance fell below the existential deposit, so the chain deleted the account and the remaining dust was lost.
Which network does KOT.CASH use for DOT?
Polkadot Asset Hub, listed by the provider as STATEMINT. Deposits are credited after 15 confirmations.
Is my DOT address the same on Asset Hub?
Yes, the same SS58 address with prefix 0 (starting with 1), but balances are kept separately on each chain.
How do I avoid reaping?
Keep the keep-alive option on and leave at least the existential deposit plus a fee reserve in the account.