> ## Documentation Index
> Fetch the complete documentation index at: https://docs.usexfg.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Understanding terms and epochs

> CD terms, epochs, and maturity heights for HEAT deposits.

## Epoch

An **epoch** is the CD accounting period. Fee accumulation and distribution are epoch-scoped.

| Network | `EPOCH_DURATION_BLOCKS` | Approx. wall time            |
| ------- | ----------------------- | ---------------------------- |
| Mainnet | **900**                 | \~**5 days** (\~480s blocks) |
| Testnet | **10**                  | Minutes-scale testing        |

Older docs that said “900 blocks ≈ 1 day” are wrong for current config comments and block-time assumptions.

## Available terms

| Bound   | Constant             | Mainnet meaning |
| ------- | -------------------- | --------------- |
| Minimum | `CD_MIN_EPOCHS = 6`  | \~1 month       |
| Maximum | `CD_MAX_EPOCHS = 72` | \~1 year        |

Wallet UIs may offer presets; protocol allows the full 6–72 range (testnet min can be 1).

## Maturity height

```
maturity_height = creation_height + (term_epochs × blocks_per_epoch)
```

Example (mainnet, 6 epochs):

* Created at height 100,000
* Term blocks = 6 × 900 = 5,400
* Maturity = 105,400

## Locked until maturity

You cannot withdraw early. Liquidity options:

1. [Transfer the CD](/features/commitment-deposits/transferring-deposits) off-chain negotiated price
2. Wait

## HEAT\_TERM vs CD term

| Term value               | Meaning                               |
| ------------------------ | ------------------------------------- |
| `HEAT_TERM` (0xFFFFFFFF) | Mint/burn marker — **not** a yield CD |
| 6–72 epochs (in blocks)  | Yield-bearing **HEAT CD**             |

## Choosing a term

Longer terms participate in more epochs of fee distribution and may receive loyalty-style bonus parameters where implemented. Shorter terms free capital sooner. [Rollover](/features/commitment-deposits/compound-interest) compounds at maturity.