Interval Timer
Your Workout. Your Rules.
What Is a Custom Interval Timer?
A custom interval timer lets you build structured work/rest programming with full control over every variable. Unlike fixed protocols like Tabata (20/10) or EMOM (work within a minute), a custom interval timer places no constraints on the format. You define the structure your training demands.
The most powerful custom timers support nested structures: sets containing rounds of work and rest, with separate rest periods between sets. This is essential for real-world programming. A strength circuit might call for 4 sets of 5 rounds (30 seconds work / 15 seconds rest) with 2 minutes of set rest between each block. A simple work/rest timer cannot express that structure. A custom interval timer can.
This nested format covers almost any training scenario. Circuit training, density blocks, sport-specific conditioning, group class programming, and complex competition prep workouts all require the ability to define sets, rounds, work time, rest time, and set rest independently.
Interval training is one of the most well-researched methods for improving cardiovascular fitness, power output, and recovery capacity. The work-to-rest ratio determines the training stimulus. Short work with long rest develops power and speed. Equal work and rest builds muscular endurance. Short rest with longer work pushes aerobic capacity. The set structure adds another layer — grouping rounds into blocks with longer recovery between them lets you maintain intensity across the full session.
The timer must clearly indicate which phase you are in — work, rest, or set rest — without requiring you to look closely at the screen. Color-coded phases, loud transition cues, and visible set and round counters are essential. If you have to stop and check the screen to know what phase you are in, the timer has failed.
BoxClock also includes Tabata Timer and EMOM Timer modes.
How BoxClock Handles Custom Intervals
- Configure sets, rounds, work time, rest time, and set rest independently
- Nested structure: sets wrap rounds of work + rest, with longer set rest between blocks
- Distinct color indicators for work, rest, and set rest phases
- Large LED countdown display for the current phase
- Audio cues fire on every phase transition — work, rest, and set rest
- Set and round counters track exactly where you are in the session
- 10-second pre-countdown before the first work interval
- Save complex configs with the bookmark feature — no re-entering every session