Date calculators · Projects & operations
Backward Scheduling Calculator
Start with the deadline. Find when each task must begin, with room for the workweek you actually have.
Your calculation
Ready when you are
Choose your dates.
Select your counting rules and calculate.
Calculation details
| Step | Value |
|---|
How to use this calculator
Enter a finish-by date and, optionally, your earliest available start. Add tasks in the order they must happen, with durations in working days. Set working weekdays, closures and a buffer after the final task. Calculate to see the latest start and whether it fits your availability.
Tasks run sequentially with no overlapping work. Every task's start and finish count toward its duration. A non-working deadline rolls back to the previous workday; buffer days occupy the last available working dates. Plans are limited to 30 tasks, 1,500 combined workdays and a ten-year calendar search. An infeasible availability date is flagged without silently moving the deadline.
A worked example
For a Friday November 20, 2026 deadline, use Design: 2 days, Build: 5 days, Review: 2 days and a one-workday buffer. With Monday–Friday work and no closures, start November 9, finish Review November 19 and reserve November 20 as the buffer.
Is this a critical-path or resource-allocation scheduler?
This tool plans a single ordered sequence. It does not calculate parallel dependencies, staff capacity or project uncertainty. Calendar exports span each task's start through finish, including any intervening weekend; the workday count follows your entered calendar.
Further reading: Microsoft Project scheduling concepts. Your entered rules determine this result.
Which calendar and years are supported?
Use Gregorian dates from 1900 through 2100. Calculations run in your browser on request. Holidays must be entered for your own workplace. Calendar downloads contain all-day markers; trip checkout dates are excluded, while project markers span through each task's finish date. Unix conversion uses UTC-year bounds and your browser's time-zone database.
What happens to my dates?
Calculations run on your device. Saving a calculation is optional and keeps it in this browser. A setup link contains the dates and settings you entered; anyone with the link can read them. Use one tab per saved calculator. Clear saved data from Privacy & settings.