Interval Timer - Tabata Timer 4+

I originally got this to use for timing Fartlek runs and speed intervals. The cycles are easy to customize and provide great feedback through sound and vibration. But then I started doing interval training at home (circuit, HIIT, and technique drills). Now I could add in visual keys and create complex hour long workouts and practices. Colors, sounds, titles, intervals, rests, cycles, repeats, all are customizable on the free app. If I could add one feature, it would be either a three period cycle or a cycle start warning, so that I can do high/low/get ready or left/right/rest. If I could make one change, it would be the ability to make a one time premium purchase instead of a subscription. I would like to put some money towards the app, perhaps for new templates (like the suggestion above) or for sharing, but I am wary of subscription services over one time purchases.
That said, I now use the premium service and is has even more flexibility, to the point that I use it over even physical timers at the gym.

I use this timer for all my workouts, whether it’s HIIT training or a standard routine, and it’s been a game-changer. I love that I can fully customize my workout and rest intervals to match my training needs for the day. Programming it is super easy, and it even displays the total workout duration and actual training time, so I don’t have to track it manually. Unlike other interval timer apps, this one doesn’t interfere with your music. The sounds are distinct, and the on-screen colors make it easy to follow along at a glance. The only downside is the occasionally long commercials, especially when you first open the app. They can be a bit annoying, but considering all the features and how well the app performs, it’s a small trade-off. Overall, it’s incredibly user-friendly, runs smoothly in the background, and does exactly what I need. Easy five stars!

This is a pretty good app for what I need it to do and for it to cost nothing. I’m satisfied.

Update:
If you want a timer app you can use without paying for, I highly recommend Interval Timer - Tabatha Timer. It’s customizable. It does have ads, but they scroll through them at the bottom of the screen while the timer is running and doesn’t interrupt your workout at all. It even runs while the app is minimized, so you can still listen for the sounds of when each interval ends, so highly useful. You can even control your music from the app. :) It does not interrupt my music playing in the background on my iOS device.

The one criticism that I’ve run across is that the app has become more glitchy as of late. I had to remove the app and add it back to my device b/c it would freeze up once I opened it. Unfortunately, doing this wiped all my saved interval timers, so I’ll have to recreate them - boo! But not a huge deal b/c they’re relatively easy to recreate. Also, after reinstalling it, I noticed that the timer occasionally freezes up or get stuck even though the timer isn’t paused, e.g., sits on 4sec left in an interval for more than 4sec. :/ I haven’t seen this happen too much yet, I only reinstalled it a week ago, but will be something I keep an eye out for, and may cause me to update my review further by dropping more stars - a timer that can’t keep time is a deal breaker.