HIIT Timer — 10 RoundsFree HIIT timer for 10 rounds. Customizable work/rest intervals for a complete 20-minute high-intensity interval workout. Start instantly.Frequently asked questionsHow long does a 10-round HIIT workout take?With 40s work and 80s rest (1:2 ratio), 10 rounds = 20 minutes. With 40s/20s (2:1 ratio), 10 rounds = 10 minutes. The timer default of 20 minutes suits an intermediate-level session.Is 10 rounds of HIIT too much?For beginners: yes — start with 5 rounds and build up. For intermediate/advanced trainees: 10 rounds at moderate intensity is a solid complete workout. The key is maintaining quality effort on each round rather than just completing the reps.What exercises should I use for 10-round HIIT?Rotate through 2–3 exercise groups to avoid local muscular fatigue: upper body (push-ups, mountain climbers), lower body (jump squats, lunges), and total-body (burpees, box jumps). Rotating lets you maintain intensity for all 10 rounds.How many calories does a 10-round HIIT workout burn?A 20-minute high-intensity session burns 150–250 calories during exercise, plus significant EPOC (afterburn). Total 24-hour caloric expenditure from a 20-minute HIIT session can equal or exceed 45 minutes of steady-state cardio.What rest period between rounds is right for 10 rounds?For fat loss/conditioning: equal rest to work time (1:1). For performance: 2× rest to work (1:2). To keep heart rate elevated: shorter rest (30s or less). Longer sessions (10 rounds) require adequate rest to maintain intensity — undercutting rest ruins subsequent rounds.