[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [Schedule](https://evolu.dev/docs/api-reference/common/Schedule) › fixed

```ts
function fixed(interval: Duration): Schedule<number>;
```

Defined in: [packages/common/src/Schedule.ts:423](https://github.com/evoluhq/evolu/blob/037c390af081e9944d616ff298a729515c5c5ab7/packages/common/src/Schedule.ts#L423)

Fixed interval schedule aligned to time windows.

Recurs on a fixed interval, outputting the repetition count (0, 1, 2, ...).
Unlike [spaced](https://evolu.dev/docs/api-reference/common/Schedule/functions/spaced), which waits a duration _after_ each execution, `fixed`
maintains a consistent cadence from the first schedule step.

If execution falls behind by one or more intervals, missed recurrences happen
immediately until the schedule catches up to the original cadence. Use
[windowed](https://evolu.dev/docs/api-reference/common/Schedule/functions/windowed) to skip missed recurrences instead.

### Maintaining a fixed cadence

```ts

// A bounded health check and an unbounded cron-like cadence.
const healthCheck = take(10)(fixed("5s"));
const cronLike = fixed("1m");

const healthDeps = testCreateDeps();
const healthStep = healthCheck(healthDeps);
assertOk(healthStep(undefined), [0, 5000]);
healthDeps.time.advance("3s");
assertOk(healthStep(undefined), [1, 2000]);
assertOk(cronLike(testCreateDeps())(undefined), [0, 60000]);
```