Minimum Balance

All Stellar accounts must maintain a minimum balance of lumens. The minimum balance is calculated using the base reserve, which is currently 0.5 XLM:

Minimum Balance = (2 + # of entries) * base reserve

The absolute minimum balance for an account is 1 XLM, which is equal to (2 + 0 entries) * 0.5 base reserve. Each additional entry reserves an additional 0.5 XLM. Entries include:

• Trustlines
• Offers
• Signers
• Data entries

For example, an account with 1 trustline and 2 offers would have a minimum balance of (2 + 3 entries) * 0.5 base reserve = 2.5 XLM.

Any transaction that would reduce an account’s balance to less than the minimum will be rejected with an INSUFFICIENT_BALANCE error. Likewise, lumen selling liabilities that would reduce an account’s balance to less than the minimum plus lumen selling liabilities will be rejected with an INSUFFICIENT_BALANCE error.

The minimum balance is held in reserve, and closing an entry frees up the associated base reserve. For instance: if you zero-out a non-lumen balance and close the associated trustline, the 0.5 XLM base reserve that secured that trustline is added to your available balance.

Validatorw can vote to change he base reserve — just as they can vote to change ledger limits and and the minimum base fee — but that’s relatively uncommon. It should only happen every few years. For the most part, you can think of the base reserve as a fixed value. When it is changed, the change works by the same consensus process as any transaction. For details, see versioning.