> For the complete documentation index, see [llms.txt](https://developers.docs.bantufoundation.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developers.docs.bantufoundation.org/glossary/minimum-balance.md).

# Minimum Balance

 This doc explains minimum balance requirements. If you want to know about transaction fees, check out the [Fees](/glossary/fees.md) doc.

All Bantu accounts must maintain a minimum balance of spirits. The minimum balance is calculated using the **base reserve,** which is currently **0.5 XBN**:

```
Minimum Balance = (2 + # of entries + # of sponsoring entries - # of sponsored entries) * base reserve 
```

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

[Sponsored Reserves](/glossary/sponsored-reserves.md) will affect the # of sponsoring entries and # of sponsored entries.

[Claimable Balances](/glossary/claimable-balance.md) are reflected in the # of sponsoring entries. Each claimant in a claimable balance will require an additional 0.5 XBN. For example, an account that creates a claimable balance with 2 claimants would have a minimum balance of `(2 + 0 entries + 2 sponsoring entries) * 0.5 base reserve = 2 XBN`.

Any transaction that would reduce an account's balance to less than the minimum will be rejected with an `INSUFFICIENT_BALANCE` error. Likewise, spirit selling liabilities that would reduce an account's balance to less than the minimum plus spirit 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-spirit balance and close the associated trustline, the 0.5 XBN base reserve that secured that trustline is added to your available balance.

## Changes to Transaction Fees and Minimum Balances

Validators can vote to change the 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](/glossary/versioning.md).