> ## Documentation Index
> Fetch the complete documentation index at: https://bun.manicule.dev/llms.txt
> Use this file to discover all available pages before exploring further.
> For every page in one file, fetch https://bun.manicule.dev/llms-full.txt (large).
> To search and read these docs as tools, connect the MCP server at https://bun.manicule.dev/api/mcp.
> Every agent surface: https://bun.manicule.dev/.well-known/llms-manifest.json

# Get the process uptime in nanoseconds (/guides/process/nanoseconds)

<!-- agent-signals: reading_time_min: 1 · est_tokens: 46 · updated: 2026-08-02 -->
Related: [Parse command-line arguments](/guides/process/argv.md), [Listen for CTRL+C](/guides/process/ctrl-c.md), [Spawn a child process and communicate using IPC](/guides/process/ipc.md), [Listen to OS signals](/guides/process/os-signals.md), [Read stderr from a child process](/guides/process/spawn-stderr.md), [Read stdout from a child process](/guides/process/spawn-stdout.md)

Use `Bun.nanoseconds()` to get the total number of nanoseconds the `bun` process has been alive.

```ts
Bun.nanoseconds();
```

***

See [Utils](/runtime/utils) for more utilities.