Pool timing fundamentals
How to use a swimming pace clock.
Read the four hands, calculate any send-off, stagger a busy lane, and know exactly when to leave again—without stopping the clock.
- Face
- 60 seconds
- Hands
- 4 colors
- Spacing
- 15 seconds
Clock basics
The face shows seconds. You keep track of minutes.
A traditional swimming pace clock completes one revolution every 60 seconds. The large second markers make it readable from the water, while four colored hands stay 15 seconds apart.
Choose one color and treat it as your clock. When that hand moves from 00 to 35, 35 seconds have passed. If more than a minute passes, count the completed minute and then read the current second.
The clock never needs to know the workout. Swimmers use the same moving hand to identify the start, finish, swimming time, rest, and next scheduled departure.
Five-step method
Use the schedule, not guesswork.
Once the hand and send-off are agreed, every repeat follows the same routine. The fixed cycle keeps the lane moving even when individual swim times vary.
- 01
Choose a clock hand
Use one colored hand as your reference. On a traditional four-hand pace clock, the hands remain 15 seconds apart so several swimmers or groups can start from different colors.
- 02
Set the send-off
Add the intended swimming time and planned rest. A 100 expected in 1:35 with 15 seconds rest uses a 1:50 send-off.
- 03
Start when your hand reaches the marker
Begin when the chosen hand reaches the agreed second marker. For a 1:50 cycle, the next start moves back 10 seconds around the face each repeat.
- 04
Read the finish and rest
Note the second where the hand points when you touch. The time remaining until the next send-off is your rest.
- 05
Repeat from the scheduled start
Leave on the send-off even when the previous repeat was faster or slower. The fixed schedule keeps the lane synchronized and exposes pace consistency.
Swimming time plus rest equals send-off.
If you expect to swim a 100 in 1:35 and want 15 seconds rest, leave every 1:50. The starting marker moves back 10 seconds around the face each repeat.
| Send-off | Marker movement | First four starts | Useful for |
|---|---|---|---|
| 1:30 | +30 seconds | 00 · 30 · 00 · 30 | Fast, easy-to-track repeats |
| 1:45 | −15 seconds | 00 · 45 · 30 · 15 | Four-repeat rotation around the face |
| 1:50 | −10 seconds | 00 · 50 · 40 · 30 | Progressive movement each repeat |
| 2:00 | Same marker | 00 · 00 · 00 · 00 | Simple fixed-minute repeats |
Need the exact pace and rest first?
Build the repeat in the pace calculator, then bring its send-off to the clock.
Busy lanes
Stagger swimmers without changing the set.
For five seconds between swimmers, assign starts at 00, 05, 10, and 15 while everyone follows the same colored hand. Each swimmer remembers their personal marker and returns to it on a fixed-minute send-off.
For larger groups, coaches can assign different hand colors to lanes or ability groups. Because the hands remain 15 seconds apart, the groups stay separated without needing several clocks.
White
Green
Yellow
Red
Four mistakes that break the rhythm.
Most pace-clock confusion comes from changing the reference in the middle of a set. Keep the hand, marker, and send-off fixed until the workout changes.
Resetting after every repeat
A pace clock is meant to keep running. Follow the scheduled send-off rather than restarting the clock when the swimmer touches.
Confusing pace with send-off
Pace is the swimming time. Send-off includes both swimming and rest, so it must be equal to or longer than the expected repeat time.
Changing color mid-set
Switching reference hands makes arithmetic harder and creates missed starts. Pick one hand and keep it until the set changes.
Leaving when rest feels complete
A fixed send-off is a schedule, not a suggested rest duration. Leave on the assigned marker to keep every swimmer synchronized.
Swimming pace-clock questions
Why does a swimming pace clock have four hands?
The four hands are usually separated by 15 seconds. They let multiple swimmers or lanes use the same clock while starting at different points, and make the face easier to read from different positions around the pool.
How do I calculate a swimming send-off?
Add the target swimming time to the planned rest. If a 100 should take 1:30 and you want 15 seconds rest, use a 1:45 send-off. The next start occurs 45 seconds after the first, then 30, 15, and 00 as the cycle moves around the clock.
What happens when the send-off is longer than one minute?
Count the full minutes mentally and use the hand for the remaining seconds. A 1:20 send-off advances the start marker by 20 seconds each repeat; a 2:00 send-off returns to the same marker.
Should I start on the red, green, yellow, or white hand?
Any color works. Choose the hand that is easiest to see and keep the same reference for the set. Coaches can assign different colors to stagger swimmers while preserving one shared send-off.
What is the difference between wall-clock and session timing?
Wall-clock mode stays aligned with the current minute, like a traditional pool clock. Session mode begins from a shared zero when you press start, which is useful when a coach wants every group synchronized to a new session clock.
Can I use a phone or tablet as a pool pace clock?
Yes. Place the device where the face is visible from the wall, use full-screen visible mode, raise brightness as needed, and protect the device from water. Keep the device connected to power for longer sessions.
Put it into practice
Open the free pace clock on any screen.
Choose wall-clock or session timing, set the send-off, enable sound if useful, and switch to the high-visibility pool view.