---
title: time.runits
summary: null
url: >-
  https://www.fastly.com/documentation/reference/vcl/functions/date-and-time/time-runits
---

```
STRING time.runits(STRING unit, RTIME rtime)
```

**Available in:** all subroutines

Returns a string representation of the given RTIME typed time value expressed
to the resolution specified by the unit.

## Parameters

- `unit` - A string of one of the four possible unit values: `s`, `ms`, `us`,
  `ns`.
- `rtime` - A time value parameter of type RTIME.

## Return Value

The return value will be of type STRING, being the text based representation of
the given time value formatted according to the unit type as specified by the
following criteria:

| Unit | Description                                                         |
| ---: | :------------------------------------------------------------------ |
|  `s` | Whole seconds only with no decimal point                            |
| `ms` | Whole seconds followed by a decimal point with three decimal places |
| `us` | Whole seconds followed by a decimal point with six decimal places   |
| `ns` | Whole seconds followed by a decimal point with nine decimal places  |

## Errors

If the `unit` argument is not a valid unit string,
then `fastly.error` will be set to `EINVAL`.

## Example

```vcl
set beresp.http.beresp-ttl-in-ms = time.runits("ms", beresp-ttl);
```