Project Deadline Calculator
Count working days, skip holidays, plan milestone dates, and back-solve schedules from total project hours.
📖 Understand this document
The deadline calculator helps you work backward from a final due date to set milestone dates, factor in buffer days, and account for non-working days like weekends and holidays.
Key components
- Final deadline — the hard due date from your client.
- Milestones — intermediate deliverable dates.
- Buffer days — extra time for revisions or unexpected delays.
- Working days only — automatically skips weekends.
Working week
Project phases
Break work into phases with duration and optional buffer. Milestones can anchor to phase ends.
Milestones
Your project
1
working days remaining
Deadline: May 26, 2026
Start: May 26, 2026
ON TRACK
| Phase | WD | Buffer | Start | End | Status |
|---|---|---|---|---|---|
| Discovery | 5 | 1 | 2026-05-26 | 2026-06-02 | not-started |
- Kickoff complete — 2026-06-02 (pending)
Works well with
Capacity Planner
Model weekly capacity against project commitments, see an eight-week forecast, and sanity-check new work before you say yes
Weekly Planner
Plan your week in a time grid with goals, recurring blocks, drag-and-resize scheduling, and reflections — saved locally in your browser
Estimate Maker
Send professional project estimates and quotes to clients
Frequently asked questions
Instead of asking when you will finish, you start from a fixed deadline and calculate the latest date you can start while still fitting the required working days.
Deadlines fail when “two weeks” means different things to different people. This calculator turns calendars into countable working days, then shows milestone cutoffs when you express progress as percentages.
Use it during scoping conversations with our estimate maker so promised dates match how you actually work—not just optimistic wall calendars.