{{ summaryHeading }}
{{ summaryPrimary }}
{{ summaryLine }}
{{ badge.label }}
Edited settings apply the next time the circuit starts.
{{ currentRemainingDisplay }} {{ currentPhaseTypeLabel }}
{{ runStateLabel }}
{{ currentPhaseTitle }}
{{ currentPhaseDetail }}
Session
{{ sessionElapsedDisplay }} / {{ activeModel.totalDisplay }}
Choose a starting circuit, then edit station names, focus, cues, and timing below.
One station per line. Plain names work; pipe-separated focus, cue, work, and transition values override defaults.
{{ rosterStatusLine }}
Set the baseline work duration for each station.
sec
Use enough time to move safely, change equipment, and reset the next station.
sec
Each round repeats the current station list in order.
rounds
Use this for water, coaching notes, and station reset before the next round begins.
sec
Pick the training lens for density and recovery guidance.
Useful when the device is across the room or a class needs a ready signal.
sec
Choose how phase changes are announced while the circuit is running.
Leave off when the timer should finish as soon as the final work block ends.
{{ include_final_transition ? 'Included' : 'Finish on last station' }}
Optional haptic cue for supported mobile browsers.
{{ vibration_enabled ? 'On' : 'Off' }}
The timer still works without wake lock; unsupported browsers simply ignore this option.
{{ keep_awake ? 'Request during run' : 'Do not request' }}
Step Phase Round Station Focus Start Duration Cue Copy
{{ phase.step }} {{ phase.typeLabel }} {{ phase.roundLabel }} {{ phase.stationName }} {{ phase.focusLabel }} {{ formatClockOffset(phase.start) }} {{ formatDuration(phase.duration) }} {{ phase.cue }}
Check Read Why it matters Action Copy
{{ check.check }} {{ check.status }} {{ check.note }} {{ check.action }}
Event Clock Phase Detail Copy
{{ event.type }} {{ event.clock }} {{ event.phase }} {{ event.detail }} 
{{ jsonPayload }}
Tags: Cardio Training, Date Time, Strength Training
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Circuit training turns a workout into a sequence of named stations, work periods, movement changes, and recovery breaks. The timing plan matters because a circuit that looks balanced on paper can feel rushed once people need to change equipment, hear the next cue, or reset before another round.

A useful circuit timer answers more than how long the session lasts. It should show when each station starts, how much of the session is work versus recovery, which movement focus dominates, and where the plan may need more reset time. Those details are especially important for group classes, home workouts with limited equipment, and coaching plans that repeat the same station list across several rounds.

Circuit timeline showing optional prep, two work stations, a movement transition, a round break, and repeated rounds.

Public health guidance describes physical activity across the week, not by one timed workout. A 20-minute circuit can contribute aerobic work, muscle-strengthening work, or both, but the timer cannot prove that a person has met weekly activity targets or chosen the right exercise intensity. The plan still needs sensible movement choices, appropriate loads, safe spacing, and enough recovery for the people using it.

The strongest circuit plans stay repeatable. Clear station names, realistic transitions, and simple cues make it easier to keep movement quality ahead of speed when the clock is running.

How to Use This Tool:

Start with a sample circuit or a custom station list, then check the live timer and result tabs before using the plan with a group or solo session.

  1. Choose a Circuit preset such as Full-body class circuit, Strength station rotation, Conditioning density circuit, or Home equipment-light. Choose Custom current roster when you want to keep the station list already on the page.
  2. Fill the Station roster with one station per line. Plain station names work, and the pipe format can override details per station: Station | focus | cue | work seconds | transition seconds. Use Normalize roster after editing if you want the parsed focus, cue, work, and transition values written back into that pipe format.
  3. Set Default station length, Default station transition, Rounds, Between-round recovery, and Session emphasis. The emphasis changes coaching checks for balanced, strength, conditioning, or technique-oriented sessions.
  4. Open Advanced when the live run needs a Start countdown, a specific Transition cue, an optional Final transition, Vibration cue, or Keep screen awake. Audio starts only after pressing Start, and unsupported vibration or wake-lock features simply stay unavailable.
  5. Review the summary and any Review the circuit setup warnings before starting. A missing roster shows Needs stations; too many station lines are capped; duplicate station names are allowed but make exports harder to read.
  6. Press Start to freeze the current run sheet for the live session. While the timer is running, Pause, Skip phase, and Reset control the current plan. If you edit settings during a run, the change applies the next time the circuit starts.
  7. Use Run Sheet, Coaching Checks, Station Flow Map, Focus Mix, and Session Ledger to verify the plan before relying on it. The run sheet is the most useful final check because it lists every phase, start time, duration, and cue in order.

If the timer says the circuit is ready but the station flow feels rushed, check Coaching Checks before changing the exercise list. The density, transition, and round-recovery rows usually show whether the issue is the work blocks or the reset time between them.

Interpreting Results:

The summary gives a first read: total session time, station count, round count, work density, and leading focus area. Treat it as a planning check, not a safety clearance. A compact circuit with high work density can still be suitable for trained participants, and a lower-density circuit can still be too hard if the exercises, load, heat, or fatigue are poorly matched.

Run Sheet is the exact schedule. It lists each phase with its Step, Phase, Round, Station, Focus, Start, Duration, and Cue. Check that start times make sense before using the live timer, especially after per-station overrides.

Coaching Checks translate the plan into review signals. Session length, Work density, Movement balance, Station logistics, and Round recovery can return labels such as Ready, Balanced, Watch, Tight, Short, Long, or High. A warning label does not automatically make the circuit unusable, but it names the part to inspect before starting.

Station Flow Map helps catch timing congestion across rounds, while Focus Mix shows where work time is concentrated by movement focus. Session Ledger records live events such as start, pause, skip, phase changes, reset, and completion. Use that ledger to explain what actually happened if a run was paused or skipped midway.

The most common false-confidence mistake is reading Ready as a guarantee that the workout fits everyone. The checks only evaluate timing structure, density, focus coverage, and simple logistics. Verify the actual exercises, equipment layout, participant readiness, and coaching supervision separately.

Technical Details:

A circuit timer is a deterministic phase builder. Station lines become work phases, transition settings become movement or setup phases, and round settings repeat the same station sequence. The clock does not estimate exertion or heart rate. It models elapsed time from the phase durations supplied by the user.

The schedule uses cumulative seconds. Each phase starts where the previous phase ends, zero-length phases are omitted, and the active timer compares elapsed time with the start and end boundaries of the frozen run sheet. That is why editing a field during a run creates a pending edit message instead of changing the live timer immediately.

Phase Construction:

Condition Phase added Start and duration rule Result label
Start countdown is greater than 0 seconds One preparation phase before the first station Starts at 0 and lasts the chosen countdown length. Prep
Each station in each round One work phase Starts at the current cursor and lasts the station work duration. Work
A station is not the last station in the round One transition phase after that station Uses the station transition duration, then advances to the next station. Transition
The round is not the final round and round recovery is greater than 0 seconds One between-round recovery phase Uses the selected recovery time before the next round begins. Round break
The final station ends and Final transition is included One cleanup transition after the last work phase Uses the final station transition duration. Transition

Work density compares active station time with transition and between-round recovery time. The start countdown is included in total session time, but it is not included in the density denominator because it happens before the circuit work/recovery pattern begins.

D = W W + R × 100 T = P + W + R
Symbol Meaning Included values
D Work density percentage Total work time divided by work plus transition/recovery time.
W Total work seconds Every station work duration multiplied by the number of rounds.
R Total transition and recovery seconds Station transitions, between-round recovery, and optional final transition.
P Preparation seconds The optional start countdown before the first work phase.
T Total session seconds Preparation, work, transitions, round breaks, and final cleanup when included.

Session emphasis changes the density review because a technique circuit should usually leave more reset time than a conditioning-density circuit. The warning rules use buffer zones around each profile rather than marking every small difference as a problem.

Session emphasis Target density Watch if below High if above Planning meaning
Technique practice 35% to 68% < 28% > 75% More reset time helps movement quality stay deliberate.
Strength stations 42% to 70% < 35% > 77% Recovery protects setup, bracing, and repeatable force output.
Balanced circuit 55% to 78% < 48% > 85% Mixed circuits need enough movement time without excessive idle time.
Conditioning density 65% to 86% < 58% > 93% Higher density is expected, but very compressed plans still need safe transitions.

Other checks are rule-based. They do not measure physiology, but they expose timing patterns that often make a circuit hard to run.

Check Rule Output effect
Session length < 8:00 is Short; > 35:00 is Watch; > 55:00 is Long. Flags unusually short, long, or fatigue-prone plans.
Movement balance Needs more than two focus groups and coverage from lower-or-hinge, upper, and core work. Returns Covered or Watch.
Station logistics For 5 or more stations, average transition below 10 seconds is Tight; average transition above 60 seconds is Watch. Highlights station changes that may be rushed or too padded.
Round recovery For multiple rounds, recovery below 30 seconds with density above 75% is Tight. Prompts a reset break when repeated rounds are dense.
Roster parsing Up to 30 station lines are used; empty-name lines are skipped; duplicate station names are allowed. Shows setup warnings when the roster needs review.
Global warning Density above 88% with more than 10 minutes of work, or a total time above 75 minutes, adds a warning. Displays an alert before the timer is run.

Station focus is inferred from either the pipe-format focus field or words in the station name. Lower, hinge, upper push, upper pull, core, cardio, mobility, and mixed focus labels feed the Focus Mix chart. A station's focus share is calculated from its work duration multiplied by the round count, so long per-station overrides can change the mix even when the roster has the same number of stations.

Duration parsing accepts plain seconds, minute-and-second text, and clock-like values such as 1:15. Default fields are clamped to practical ranges: station length 10 to 300 seconds, transition 0 to 180 seconds, rounds 1 to 12, between-round recovery 0 to 300 seconds, and start countdown 0 to 60 seconds. Per-station pipe overrides can use 5 to 600 seconds for work and 0 to 300 seconds for transition.

Limitations:

This is a timing and planning aid, not a medical, rehabilitation, or personal-training prescription. It cannot know the user's health status, exercise technique, load selection, pain, environment, heat stress, or recovery capacity.

  • Official activity guidance is weekly and person-specific; one circuit run does not prove that aerobic or muscle-strengthening recommendations have been met.
  • Audio, voice, vibration, and screen wake behavior depend on browser and device support after the timer is started.
  • Browser timers can drift slightly if the device sleeps, the tab is heavily throttled, or the system is under load. Use the run sheet for the planned schedule and the live timer for practical session cues.
  • Station names and cues can contain sensitive participant or class information. Routine modeling happens in the browser, and chart rendering may use network-loaded charting code. Copied links, downloads, and shared files should be handled like workout notes.

Worked Examples:

Full-body class circuit

The Full-body class circuit preset uses 6 stations, 45 seconds per station, 15-second transitions, 3 rounds, 60 seconds between rounds, and a 10-second start countdown. Run Sheet starts with Prep, then repeats the station work and transition pattern across all rounds. The summary shows 19m 25s total, 13m 30s work, and about 70% work density. Coaching Checks should read as a balanced plan because movement coverage includes lower, upper, core, and cardio work, and the transition time is not unusually tight.

Dense conditioning plan

A custom conditioning session with 5 stations, 45-second work blocks, 0-second transitions, 3 rounds, and no between-round recovery creates 11m 15s of work with 100% work density, plus any start countdown. Coaching Checks marks Work density as High, Station logistics as Tight, and Round recovery as Tight. The alert also warns when high density is paired with more than 10 minutes of total work, so the practical correction is to add transition or round recovery before using it with mixed-ability participants.

Roster parsing correction

A roster line such as | core | Brace and breathe | 40 | 10 has no station name, so the setup alert reports that the line was skipped. The timer may still run if other valid stations remain, but Run Sheet and Focus Mix will omit that unnamed station. Add a name, for example Dead bug | core | Brace and breathe | 40 | 10, then check the roster status line and Run Sheet before pressing Start.

FAQ:

What does work density mean?

Work density is total station work time divided by station work plus transition and round-recovery time. The start countdown is part of total time, but it is not part of the density calculation.

Can each station have its own time and cue?

Yes. Use the pipe format in Station roster: station name, focus, cue, work duration, and transition duration. The Normalize roster button rewrites the parsed roster so those values are easier to review.

Why did my running timer not change after I edited the settings?

Pressing Start freezes the current run sheet for that session. Edits made while the timer is running or paused apply after reset or the next start, which prevents mid-phase timing changes from shifting the active schedule unexpectedly.

Why are sound, vibration, or screen wake cues unavailable?

These cues depend on the browser and device. Audio begins only after pressing Start, voice cues require speech support, vibration requires mobile browser support, and screen wake uses the browser wake-lock feature when available.

Does a Ready label mean the workout is safe?

No. Ready means the timing structure passed the local checks. Exercise selection, load, movement skill, health status, supervision, and environmental conditions still need a separate review.

Are my station names sent away for timing?

The schedule, charts, live timer, and exports are built in the browser. Shared links or downloaded files may include station names, cues, and settings, so avoid putting private participant details in the roster unless that sharing is intentional.

Glossary:

Station
A named exercise or task block that receives a work duration, movement focus, and cue.
Work phase
The active timed period for a station in a round.
Transition
The movement or setup time after a station before the next station begins.
Round break
The recovery period between repeated passes through the station roster.
Work density
The percentage of work-and-recovery time spent in station work.
Focus Mix
The result view that groups station work seconds by movement focus.
Session Ledger
The live event record for starts, pauses, skips, phase changes, resets, and completion.
Wake lock
A browser feature that can ask the device to keep the screen awake during an active run.

References: