Time Tutor is on the App Store. It’s my second iOS app to get through review, a week after Moons, and of the two this is the one that’s closest to my heart. It’s a small app. It does one thing. But I built it for my son, and he’s the reason it exists at all.

It started as a web page

My son was learning to tell the time, and the 24-hour clock was the bit that kept tripping him up. Half past three is 15:30, and every app or worksheet we tried treated that as a footnote. They’d drill the 12-hour face, or show a digital readout, and leave the jump between the two for me to explain at the kitchen table.

So I built him a clock. When I want to make something, I reach for the web. It’s what I know, it’s what I think in, and I can have something on a screen in an hour. The first version was a single clock face with the 12-hour numbers on the inner ring and the 24-hour numbers on the outer one, and the same hands pointing at both. Drag the hour hand round and 3 becomes 15 right in front of you. That was the whole idea, and it worked on him, so I tidied it up and put it in my lab.

I iterated on it there for a while. The sky behind the face started sliding from night through morning to afternoon as the hands moved, so the time got a feel as well as a number. A quiz turned up, then difficulty levels. It was a nice little web app and I was happy with it.

Then it became an app

At some point it clicked that this thing would make a much better iPhone app than a web page, mostly because of the hands. The web version handled dragging a clock hand round with your finger fine, but as a native app it’s faster and more responsive, and that matters a lot when the whole app is a hand you drag. Touch is where native earns its keep.

So I converted it, with a lot of help from Claude Code. Everything is SwiftUI with no external libraries at all, and I pushed to keep it as native as I could. The payoff is the same one I got with Moons. The download is 11.2 MB. An app that teaches a child to read a clock has no business being any bigger than that.

What’s in it:

• Both clocks on one face, sharing the same hands
• The sky changes with the time of day
• Three levels, from every number labelled down to a bare 12-hour face
• A quiz that marks you and explains the arithmetic rather than just congratulating you
• Hands linked like a real clock, or switched to move one at a time
• VoiceOver reads the face, and both hands work with it

No account, no network, no ads. It works on a plane and in a classroom with no wifi.

This was my first proper app in Swift. I’d written a native app for Otter before this, but that wasn’t a full application when I started, more a client for an API I already had. Time Tutor was the first time I built the whole thing, screen by screen, and had to make it feel like it belonged on the phone. It taught me most of what I then used on Moons.

What it costs

£0.99, or $0.99, once. No subscription, no in-app purchases. I don’t expect to make much money from this, and that’s fine. But it’s worth saying that the web version made nothing at all. A web page is very hard to charge for, and an app on the App Store isn’t, so even a tiny amount of money is some return on the time it took to build. It scratched an itch, it helped my son, and if it helps a few other kids learn the time then it’s done its job.

Go and have a play with it, and let me know what you think. I’d love to hear if it works for your kids too.