# Derive principal addresses between networks

{% code fullWidth="false" expandable="true" %}

```clarity
;; Extract hash bytes from an address
(define-read-only (get-address-hash-bytes (address principal))
  (get hash-bytes (unwrap-panic (principal-destruct? address)))
)

;; Convert testnet address to mainnet
(define-read-only (testnet-to-mainnet (testnet-address principal))
  (let (
    ;; Extract the hash bytes from testnet address
    (hash-bytes (get-address-hash-bytes testnet-address))
    ;; Mainnet version byte
    (mainnet-version 0x16)
  )
    ;; Reconstruct with mainnet version
    (principal-construct? mainnet-version hash-bytes)
  )
)

;; Convert mainnet address to testnet
(define-read-only (mainnet-to-testnet (mainnet-address principal))
  (let (
    ;; Extract the hash bytes from mainnet address
    (hash-bytes (get-address-hash-bytes mainnet-address))
    ;; Testnet version byte
    (testnet-version 0x1a)
  )
    ;; Reconstruct with testnet version
    (principal-construct? testnet-version hash-bytes)
  )
)

;; Example usage
(testnet-to-mainnet 'ST1PQHQKV0RJXZFY1DGX8MNSNYVE3VGZJSRTPGZGM)
;; Returns: (ok SP1PQHQKV0RJXZFY1DGX8MNSNYVE3VGZJSRCBGD7R)
```

{% endcode %}

### Description

Convert addresses between mainnet and testnet by extracting and reconstructing with different version bytes

### Use Cases

* Cross-network address verification
* Building multi-network dApps
* Address validation tools
* Network migration utilities

### Key Concepts

* **Version byte** - Indicates network and address type
* **Hash bytes** - 20-byte hash of the public key
* **Checksum** - Built into the c32 encoding
* Version bytes: 0x16 (Mainnet SP), 0x17 (Mainnet SM), 0x1a (Testnet ST), 0x1b (Testnet SN)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.stacks.co/cookbook/clarity/address-utilities/derive-principal-addresses-between-networks.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.