What step formats are supported?

A whole number followed by a unit letter: "s" for seconds, "m" for minutes, or "h" for hours, for example "15m" or "2h". The number must be positive.

What happens when the sequence passes midnight?

Times wrap around using a 24-hour clock, so a sequence that starts at 23:00 and steps by 30m continues at 23:30, then 00:00, then 00:30, and so on.

Can the step go backward in time?

No, the step is always a positive forward interval. To generate a descending sequence, reverse the output afterward or start from the later time and reason about it in reverse.

How many times can be generated at once?

Up to 10,000 in a single run, enough for a full week of minute-level scheduling in one pass.

Time Sequence Generator - Generate a List of Times at a Fixed Interval

Overview

Introduction

Recurring schedules, whether it's a shift roster, a set of reminder alarms, or timestamps for a test fixture, often need a plain list of evenly spaced clock times.

This tool builds that list for you: give it a starting time, a step, and a count, and it returns every time in the sequence.

What Is Generate a Time Sequence?

A time sequence generator that produces a fixed number of clock times, each one step duration after the previous, starting from a chosen HH:MM:SS time.

It operates on a 24-hour clock and wraps naturally past midnight, so overnight sequences come out correct without any extra handling.

How Generate a Time Sequence Works

The start time and step duration are converted to seconds since midnight and a per-step second count respectively.

Each output time is the start plus a whole multiple of the step, taken modulo the number of seconds in a day and formatted back to HH:MM:SS.

When To Use Generate a Time Sequence

Use it to lay out a recurring meeting schedule, a set of alarm times, or a series of timestamps for test data.

It's also useful for generating checkpoint times for a shift, a broadcast schedule, or an automated task that should fire every N minutes.

Often used alongside Generate a Date Sequence and Split Date into Intervals.

Features

Advantages

Correctly wraps past midnight, no manual adjustment needed for overnight sequences.
Supports second, minute, and hour steps for flexible granularity.
Generates up to 10,000 times in one pass.

Limitations

Only forward, positive steps are supported, there's no built-in reverse or negative step.
The sequence doesn't carry date information, only the time of day.

Examples

Six 15-minute slots starting at 9 AM

Input

09:00:00
15m
6

Output

09:00:00
09:15:00
09:30:00
09:45:00
10:00:00
10:15:00

Each line steps 15 minutes forward from the last, starting at 09:00:00.

Best Practices & Notes

Best Practices

Match the step unit to the schedule granularity you actually need, minutes for meeting slots, hours for shift boundaries.
If you need dates attached to each time, pair the output with Date Sequence Generator's dates line by line.

Developer Notes

The step regex requires a positive integer immediately followed by s, m, or h (case-insensitive); each output time is `(start + i * step) mod 86400` seconds, formatted with zero-padded two-digit hours, minutes, and seconds, which is what makes the midnight wraparound automatic rather than a special case.

Generate a Time Sequence Use Cases

Building a list of recurring meeting or shift start times
Generating alarm or reminder times spaced by a fixed interval
Producing timestamp fixtures for tests that need evenly spaced clock times

Common Mistakes

Leaving off the unit letter on the step line, entering "15" instead of "15m".
Expecting a negative or zero step to work, both are rejected since the sequence must move strictly forward.

Tips

Use an "h" step for coarse daily schedules and switch to "m" or "s" when you need finer granularity.
Combine with Date Sequence Generator to build a full date-and-time schedule from two short inputs.

Generate a Time Sequence