How many rounds of HIIT? Work-to-rest ratios and rounds
The number of rounds in a HIIT session is the total time divided by one round (work + rest), rounded down. The table does that for the common interval pairs.
Rounds by interval and session length
| Work / rest | Ratio | 10 min | 15 min | 20 min | 30 min | Timer |
|---|---|---|---|---|---|---|
| 20s / 10s | 2:1 | 20 | 30 | 40 | 60 | Timer |
| 30s / 15s | 2:1 | 13 | 20 | 26 | 40 | Timer |
| 40s / 20s | 2:1 | 10 | 15 | 20 | 30 | Timer |
| 45s / 15s | 3:1 | 10 | 15 | 20 | 30 | Timer |
| 30s / 30s | 1:1 | 10 | 15 | 20 | 30 | Timer |
| 60s / 60s | 1:1 | 5 | 7 | 10 | 15 | Timer |
| 20s / 40s | 1:2 | 10 | 15 | 20 | 30 | Timer |
| 60s / 30s | 2:1 | 6 | 10 | 13 | 20 | Timer |
Rounds are whole rounds; any leftover seconds are not counted. For a different pair, use the interval workout calculator or set your own numbers in the interval timer.
Questions
How many rounds of 40/20 fit in 20 minutes?
20 rounds. Each round is 60 seconds.
How many rounds of 30/30 fit in 15 minutes?
15 rounds.
What does a 2:1 ratio mean?
Work is twice as long as rest, for example 40 seconds work and 20 seconds rest.
How do I work out the number of rounds?
Divide the total time in seconds by the length of one round (work + rest) and round down.
Timers for this
HIIT Timer
10 rounds · 30s work / 30s rest · 10m
HIIT Timer — 40/20
8 rounds · 40s work / 20s rest · 8m
HIIT Timer — 45/15
8 rounds · 45s work / 15s rest · 8m
HIIT Timer — 30/15
10 rounds · 30s work / 15s rest · 7m30s
20-Minute HIIT Timer
20 rounds · 40s / 20s · 20 min
Interval Timer
Custom work / rest / rounds · default 10 × 30s / 30s
Other guides
- How long is a Tabata?
- How long is a boxing round?
- EMOM vs AMRAP
- Interval workout time calculator
- The Flowtime technique
General information, not medical advice.
Pulse for iPhone and Apple Watch
The same kind of timer as an app. Free download; Pulse Pro is $3.99 once. No subscription, no ads.
168 palettes8 free, all 168 with Pro.
Apple WatchSaved interval timers run on the watch, with a haptic at each transition.
Live ActivityThe countdown shows on the Lock Screen and in the Dynamic Island.
Saved timers3 free, unlimited with Pro. Flow sessions, labels and history.