# Schedule Syntax

This page lists the spec formats `Add` accepts: five-field cron expressions, descriptors, and `@every` intervals.

## Cron Expressions

Exactly five fields, evaluated in the configured `Location`:

| Field | Range |
|---|---|
| Minute | 0-59 |
| Hour | 0-23 |
| Day of month | 1-31 |
| Month | 1-12 |
| Day of week | 0-6 (0 is Sunday) |

| Syntax | Example | Matching rule |
|---|---|---|
| `*` | `*` | Any value |
| `n` | `30` | Equals n |
| `n-m` | `9-17` | Between n and m inclusive |
| `a,b,n-m` | `0,30` | List, ranges allowed, duplicates removed |
| `*/n` | `*/15` | Field value divisible by n |

`*/n` tests the field value itself, not an offset from the field minimum: `*/5` in the day-of-month field matches days 5, 10, 15, 20, 25, and 30, and `*/2` in the month field matches even months. `n-m/s` and month or weekday names are not supported. The next fire time starts at the following minute and advances minute by minute until all five fields match.

## Descriptors and Intervals

| Spec | Equivalent |
|---|---|
| `@yearly`, `@annually` | `0 0 1 1 *` |
| `@monthly` | `0 0 1 * *` |
| `@weekly` | `0 0 * * 0` |
| `@daily`, `@midnight` | `0 0 * * *` |
| `@hourly` | `0 * * * *` |
| `@every <duration>` | Parsed by `time.ParseDuration`; minimum 30 seconds; next fire = time the trigger was handled + duration |

See [Configuration](/configuration#scheduler-settings) for setting the timezone and [Task API](/api-reference-tasks#add) for parse errors.