Preparation, outbound recovery, critical work, and home return on one phase timelineLive current inputs
Date & Time
Jet Lag Timeline Calculator
Lay out pre-adaptation, outbound travel, destination adjustment, critical work, return travel, and home readjustment on one continuous timeline so each operational event can be compared with the modeled body-clock state.
Shift completed before departure—
Residual on arrival—
Residual on critical workday—
Destination alignment day—
Clock shift carried home—
Home realignment day—
Total modeled timeline—
Critical-work timing—
Dual-leg circadian ribbon
Preparation, outbound recovery, critical work, and home return on one phase timeline
A continuous ribbon changes color by stage while a body-clock line shows pre-shift, destination convergence, the return shock, and home readjustment.
Operational event timeline
Phase state at each travel and work checkpoint
Checkpoints preserve the order of events and make it clear when critical work occurs before destination alignment.
| Checkpoint | Timeline day | Stage | Clock shifted | Residual offset | Operational meaning |
|---|
Timeline setup
Place the demanding event inside the travel sequence
- Enter the geographic clock shift and outbound direction.
- Reserve only preparation days you can actually follow.
- Enter the number of destination days before returning.
- Place the critical event on its real day after arrival.
- Use separate adaptation rates for destination and home recovery.
State propagation
The return shock depends on how far the clock moved while away
A traveler who never fully adapts at destination does not return with a full reverse shift. The model carries the achieved phase movement into the homebound leg rather than resetting at either flight.
The critical-event marker is evaluated against the residual on that exact destination day. Moving the event later can improve the phase position without changing flight dates.
Calculation method
Propagate body-clock state through both travel legs
Pre-adaptation removes part of the outbound displacement. Destination adjustment continues during the stay. The return shock equals the total clock movement completed away from home and is then reduced at the home rate.
Detailed calculation process and general formulas
S_pre = min(Δ, P × r_p)R_arr = Δ - S_preS_away(t) = min(R_arr, t × r_a)R_crit = max(R_arr - d_c × r_a, 0)S_home = S_pre + min(R_arr, L × r_a); t_home = S_home / r_hSymbols, meanings, and units
- Δ
- full destination clock displacementhours
- P, L
- pre-adaptation days and destination staydays
- r_p, r_a, r_h
- preparation, away, and home phase rateshours/day
- d_c
- destination day of the critical work eventdays after arrival
- R_arr, R_crit
- residual offset at arrival and critical workhours
Agenda design
Checkpoints for protecting demanding work
The timeline turns a general recovery estimate into a sequence of operational decisions.
Arrival state
—Unresolved displacement after pre-adaptation.
Critical work
—Residual offset on the selected demanding day.
Return shock
—Phase movement that must be reversed at home.
Home alignment
—Timeline day when modeled home realignment completes.
Decision takeaway: Move critical work later, add pre-adaptation, or lengthen recovery when the event sits inside the steepest part of the phase ribbon.
Timeline controls
Events that deserve explicit placement
- Overnight flight and arrival day
- First safety-sensitive activity
- Critical negotiation or examination
- Return-day commute or shift
- Recovery days before normal duty
Timeline evidence
Documents to align before approving the agenda
- Door-to-door itinerary
- Local agenda with start times
- Planned sleep opportunities
- Destination and home duty rosters
- Previous trip recovery observations
Practical applications
Decisions this calculator is designed to support
Technical commissioning visit
A traveler crosses ten hours east, works a critical site day two, and returns after eight days.
What the result clarifies: The critical marker quantifies how early the task falls in destination adaptation.
Short executive round trip
A traveler pre-shifts for three days but stays only four days.
What the result clarifies: The return shock may be smaller than the destination offset because alignment never finishes.
Worked example
Current-input substitution and reconciliation
Model limitations
The timeline is deterministic and does not predict alertness, medical safety, or exact circadian phase. Travel fatigue, sleep loss, illness, chronotype, irregular duty, medication, and light timing can materially change outcomes.
Jet Lag Timeline Calculator FAQ
Why is the home return shock not always the full time-zone difference?
It equals the clock movement actually completed away from home, which can be smaller on a short trip.
What does critical day zero mean?
The demanding event occurs on arrival day before any full destination-recovery day is credited.
Can pre-adaptation eliminate arrival residual?
Only if the entered preparation days and rate cover the entire clock displacement; the model caps pre-shift at that displacement.
Does the timeline include flight duration?
It focuses on phase-state days around arrival and return; use the itinerary itself for elapsed travel duration.