Weekly allocation bars crossing the ISO week-year seamLive current inputs
Date & Time
Week Number Schedule Calculator
Build an ISO-week delivery plan that carries a numeric target across ramp, steady, blackout, and close weeks without losing the year boundary or hiding the weekly capacity constraint.
Schedule ending week—
Steady weekly allocation—
Peak weekly allocation—
Blackout-week allocation—
Peak capacity margin—
ISO week-year boundaries—
Target completion week—
Schedule feasibility—
ISO week cadence ridge
Weekly allocation bars crossing the ISO week-year seam
Ramp and close shoulders frame the delivery ridge, the blackout notch stays visible, and a cumulative line proves that the full target survives the calendar transition.
Week-by-week delivery ledger
ISO labels, phase weights, planned units, and capacity margin
Use the ledger to audit every label at a 52- or 53-week year boundary and identify the exact week that completes the target.
| ISO week | Phase | Weight | Planned units | Cumulative | Capacity | Margin |
|---|
Schedule setup
Anchor the plan to a real ISO week-year
- Enter the ISO week-year and starting week shown by the governing calendar.
- Choose the number of weekly planning buckets.
- Set the total output that must be completed inside the horizon.
- Reserve ramp, close, and one known blackout week.
- Compare the resulting peak with demonstrated weekly capacity.
Week-year logic
Week 01 can begin before January 1
ISO weeks start on Monday and week 01 is the week containing January 4. The schedule advances by actual ISO-week labels instead of assuming every year has 52 weeks.
A blackout is not deleted from the calendar. It remains as a zero-output slot, so downstream work moves to the remaining weighted weeks and the capacity consequence is explicit.
Calculation method
Normalize phase weights before assigning the target
Each schedule week receives a phase weight. A blackout week receives zero, ramp and close weeks receive reduced weights, and steady weeks receive one. Dividing the target by total weight preserves the target before capacity is tested.
Detailed calculation process and general formulas
w_i = phaseWeight(i); blackout week: w_i = 0W = sum(i=1..n) w_ib = T / Wq_i = b * w_i; Q_i = sum(j=1..i) q_jmargin_peak = C - max(q_i)Symbols, meanings, and units
- T
- total delivery targetunits
- w_i
- phase weight assigned to ISO week idimensionless
- b
- steady-week allocation before capacity testingunits/week
- q_i
- planned allocation in week iunits
- C
- maximum deliverable weekly capacityunits/week
Cadence decisions
Four checks before approving the weekly plan
Target preservation, label accuracy, capacity, and completion timing answer different planning questions.
Calendar landing
—The exact ISO week in which the schedule ends.
Steady burden
—The normalized load carried by a full-weight week.
Constraint signal
—Capacity left after the most demanding week.
Delivery evidence
—The first week whose cumulative allocation reaches the target.
Decision takeaway: Approve the schedule only when the target reconciles and the ridge remains under real weekly capacity.
Planning controls
Challenge the week plan before it becomes a commitment
- Confirm the calendar uses ISO rather than US week numbering.
- Model known shutdowns as visible zero-output weeks.
- Use sustainable, not record, weekly capacity.
- Rebalance after changing ramp or close assumptions.
Schedule evidence
Records that make the allocation defensible
- Published ISO planning calendar
- Historical weekly throughput
- Approved blackout calendar
- Backlog or target source
- Capacity and staffing roster
Practical applications
Decisions this calculator is designed to support
Cross-year release train
A product group schedules 7,200 validation units from ISO week 47 through the new year with a holiday blackout.
What the result clarifies: The ridge keeps week 53 or week 01 labels correct while redistributing the lost week.
Seasonal fulfillment plan
An operations team ramps for two weeks, sustains output, then tapers into a close period.
What the result clarifies: The capacity line reveals whether the weighted plan is deliverable before dates are promised.
Worked example
Current-input substitution and reconciliation
Model limitations
This is a deterministic allocation model. It does not sequence individual tasks, resolve daily holidays, optimize staffing, or guarantee throughput. Week labels follow ISO 8601; organizations using Sunday-start or non-ISO fiscal weeks need a different calendar.
Week Number Schedule Calculator FAQ
Why can an ISO year contain week 53?
A year has week 53 when its ISO-week structure requires a final Monday-to-Sunday week before the next week-year begins.
Does the blackout week disappear?
No. It remains in the schedule with zero allocation, forcing the target into the other weeks.
Why is the steady load not target divided by weeks?
Ramp, close, and blackout weights reduce effective full-load weeks, so the normalized base must use total phase weight.
What happens when peak load exceeds capacity?
The plan is infeasible without more capacity, a longer horizon, a smaller target, or different phase weights.