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Methodology

Four-Day Workweek Calculator methodology

Compare two workweeks using entered pay, work time and commute assumptions.
Duc Nguyen X.By Duc Nguyen X.· Founder, Wage101Last reviewed: View update historyMethodology

Educational only: Work and pay decision support, not tax, legal, financial or career advice.

Privacy: Calculations run locally; Wage101 does not receive your work or pay inputs.

Update policy: Reviewed when formulas or official dependencies change.

Scope: Market-neutral work and pay planning using your own assumptions.

1. Formulas and units

Committed-time comparison
annualHoursSaved = currentCommittedHours − proposedCommittedHours

Where

annualHoursSaved
Annual committed hours saved (hours/year)Source: Calculated output
currentCommittedHours
Current Committed Hours (hours/year)Source: Calculated output
proposedCommittedHours
Proposed Committed Hours (hours/year)Source: Calculated output
Annual commute cost saved
annualCommuteCostSaved = currentCommuteCostPerDay × currentWorkDaysPerWeek × paidWeeksPerYear − proposedCommuteCostPerDay × proposedWorkDaysPerWeek × paidWeeksPerYear

Where

paidWeeksPerYear
Paid weeks per year (weeks/year)Source: Work record
currentWorkDaysPerWeek
Current workdays (days/week)Source: Work record
currentCommuteCostPerDay
Current daily commute cost (currency units/day)Source: Work record
proposedWorkDaysPerWeek
Proposed workdays (days/week)Source: User decision
proposedCommuteCostPerDay
Proposed daily commute cost (currency units/day)Source: User decision
annualCommuteCostSaved
Annual commute cost saved (currency units/year)Source: Calculated output
Annual pay difference
annualPayDifference = proposedAnnualPay − currentAnnualPay

Where

currentAnnualPay
Current annual pay (currency units/year)Source: Work record
proposedAnnualPay
Proposed annual pay (currency units/year)Source: User decision
annualPayDifference
Annual pay difference (currency units/year)Source: Calculated output
Adjusted hourly value difference
commuteAdjustedHourlyValueDifference = proposedCommuteAdjustedHourlyValue − currentCommuteAdjustedHourlyValue

Where

commuteAdjustedHourlyValueDifference
Adjusted hourly value difference (currency units/hour)Source: Calculated output

Money inputs and outputs use the currency selected in the scenario without changing the canonical methodology. Pay, time, benefits and work-related costs use the units stated beside each input.

2. Worked example

Input assumptions

Compare 40 hours over five days with 32 hours over four days at the same annual pay.

Calculation and outputs

Example

Compare 40 hours over five days with 32 hours over four days at the same annual pay.

Annual committed hours saved
468
Annual commute cost saved
520.00 currency units
Annual pay difference
0.00 currency units
Adjusted hourly value difference
8.55 currency units

Time, commute cost and pay differences remain visible rather than collapsing to one score.

Interpretation

Use the schedule comparison with time, commute and pay differences kept separate.

3. Validation and boundary checks

  • Both schedules use the same paid weeks.
  • Committed hours include work and commute time.
  • Pay and weekly hours must be positive.

4. Assumptions and source classification

  • Commute figures are round-trip per workday.
  • Schedules repeat for every entered paid week.
  • No tax or local work rule is applied.

This calculator has no current policy-data dependency. Its work and pay assumptions are user supplied. Registered family-level regression suites exercise the shared work-logic engine and worked-result reconciliation.

5. Limitations

  • A four-day schedule may redistribute rather than reduce hours.
  • Work intensity and flexibility are not valued.
  • Commute conditions can vary.

This is educational decision support, not personalised tax, legal, financial or career advice. Check the treatment of your circumstances under the rules that apply to you and seek qualified advice where appropriate.

6. Update and evidence policy

Registered family-level suites test formula invariants and example reconciliation; the release ledger records that coverage without claiming a separate oracle for every line of public copy. There is no official threshold or benchmark to refresh for this calculator. Work and pay inputs remain user-supplied because they vary by person, job and contract.

Change history

  1. : Initial public release of the Four-Day Workweek planner and methodology.

Related reading

Use these practical guides to interpret the decision and its assumptions.

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