Try the tool

Runs in this page. Your inputs are not uploaded or saved. Dates use your browser’s time zone.

Your result

Choose a reference time, a reminder time, and repeat days. The result is the next matching time strictly after the reference time.

A worked example

A weekday reminder at 8:30 AM, planned from Friday after 8:30 AM, next falls on Monday at 8:30 AM.

This is a schedule illustration

The planner uses the browser's time zone and omits a local time skipped by daylight saving. It does not create a reminder. Configure Reminders in the app, where permissions, Focus, Travel mode, and an already checked routine affect delivery.

Keep the next check on your iPhone

Create the items manually in Is It Locked?. This browser draft does not transfer into the app. Check the items yourself, then record them.

Get the app free

iOS 27 or later. One place and one list are free.

The app records what you checked. It does not lock doors, switch off appliances, or verify their physical state.

Sources and review notes

Calculation conventions and boundary cases are documented above. The tool runs locally and is tested against arithmetic and calendar examples.