# Klaytn native coin - KLAY

## KLAY <a href="#klay" id="klay"></a>

KLAY is the main internal transferable cryptocurrency of Klaytn and is used to pay transaction fees when creating or executing smart contracts or when transferring KLAY.

KLAY is a necessary element--a fuel--for operating the Klaytn distributed application platform. It is a form of payment made by the clients of the platform to the consensus nodes (CNs) executing the requested operations. To put it another way, KLAY is an incentive; it ensures that developers write high-quality applications (wasteful code costs more) and that the network remains healthy (CNs are compensated for the resources they contribute).

## Units of KLAY <a href="#units-of-klay" id="units-of-klay"></a>

Klaytn uses the following unit system for KLAY.

* `peb` is the smallest currency unit.
* `ston` is an alias for `Gpeb` and introduced for convenience.
* A `KLAY` is 10^18 peb.

| Unit  | peb value | peb                                       |
| ----- | --------- | ----------------------------------------- |
| peb   | 1 peb     | 1                                         |
| kpeb  | 10^3 peb  | 1,000                                     |
| Mpeb  | 10^6 peb  | 1,000,000                                 |
| Gpeb  | 10^9 peb  | 1,000,000,000                             |
| ston  | 10^9 peb  | 1,000,000,000                             |
| uKLAY | 10^12 peb | 1,000,000,000,000                         |
| mKLAY | 10^15 peb | 1,000,000,000,000,000                     |
| KLAY  | 10^18 peb | 1,000,000,000,000,000,000                 |
| kKLAY | 10^21 peb | 1,000,000,000,000,000,000,000             |
| MKLAY | 10^24 peb | 1,000,000,000,000,000,000,000,000         |
| GKLAY | 10^27 peb | 1,000,000,000,000,000,000,000,000,000     |
| TKLAY | 10^30 peb | 1,000,000,000,000,000,000,000,000,000,000 |

#### APIs Related to KLAY Units <a href="#apis-related-to-klay-units" id="apis-related-to-klay-units"></a>

`klay.toPeb` and `klay.fromPeb` are convenient APIs for converting between KLAY units.

```
$ ./klay attach data/dd/klay.ipc
...
> klay.fromPeb(25, "peb")
"25"
> klay.fromPeb(25, "Gpeb")
"0.000000025"
> klay.fromPeb(25, "ston")
"0.000000025"
> klay.fromPeb(25, "KLAY")
"0.000000000000000025"
> klay.toPeb(25, "peb")
"25"
> klay.toPeb(25, "ston")
"25000000000"
> klay.toPeb(25, "KLAY")
"25000000000000000000"
```

You can get the list of all units supported by `klay.toPeb` and `klay.fromPeb` by sending an invalid unit string such as the one below.

```
> klay.toPeb(1, "something-does-not-exist")
Error: This unit doesn't exist, please use one of the following units
"noKLAY": "0"
"peb": "1"
"kpeb": "1000"
"Mpeb": "1000000"
"Gpeb": "1000000000"
"ston": "1000000000"
"uKLAY": "1000000000000"
"mKLAY": "1000000000000000"
"KLAY": "1000000000000000000"
"kKLAY": "1000000000000000000000"
"MKLAY": "1000000000000000000000000"
"GKLAY": "1000000000000000000000000000"
"TKLAY": "1000000000000000000000000000000"

    at web3.js:2170:19
    at web3.js:2255:49
    at <anonymous>:1:1
```


---

# 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://archive-docs.klaytn.foundation/content/klaytn/design/klaytn-native-coin-klay.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.