Calculate a project duration and completion date online: add a duration to a start date, count working days between two dates, or back-schedule a start date, with weekends and statutory holidays excluded and makeup workdays included
Use this when weather or a work stoppage delays the project; the value is added to the completion date in calendar days.
One date per line or comma-separated, formatted as 2026-12-24. Use this to add holidays for years that are not built in, or to match your own company calendar.
* Holiday and makeup-workday data comes from the General Office of the State Council's annual Notices on Holiday Arrangements (2024-2026). The next year's arrangement is usually published around November, so dates outside the built-in range can be added under "custom rest days / makeup days" above. Results are for reference only; contract schedules should follow the parties' agreement.
Find a completion date, measure a duration, or back-schedule a start date — forward and backward planning in one place.
Count every calendar day, or count only days that skip weekends and holidays. Switch with one click.
China's 2024-2026 holiday arrangements are included; holidays are skipped and makeup workdays still count as working days.
Two-day weekends, single-day weekends or rotating shifts — pick whichever days your organisation actually rests.
Add a delay for work stoppages, and enter holidays or makeup days manually for years that are not built in.
All calculations run inside your browser. Dates and durations are never uploaded and no sign-up is needed.
Pick "Completion date" when you know the start date and duration, "Duration" when you know both dates, or "Back-schedule" to work backwards from a deadline.
Select the start date (or end date), type the duration, and choose whether to count in calendar days or working days.
Change the weekly rest days, toggle statutory holidays and makeup workdays, and add an extension if work was delayed.
The result panel shows the completion date (or start date) with its weekday plus a breakdown of calendar days, working days, weekends and holidays. Click "Copy result" to paste it anywhere.
Work out the completion date from a start date and agreed duration, avoiding holidays and weekends when booking deliveries and inspections.
Check whether a tender's required calendar-day or working-day duration is achievable before you bid.
Back-schedule the latest date to submit a leave request from the day you need to be back, counting working days only.
Work backwards from a delivery deadline to set the latest finish date for each stage, with buffer built in.
Estimate production lead times and arrival dates in working days; the difference before and after holidays becomes obvious.
Convert a "within N working days" requirement into a real date so you never miss a registration or payment window.
Calendar days are counted one by one through the calendar, including weekends and holidays. Working days count only days on which work can actually proceed, so weekends and statutory holidays are skipped and makeup workdays are treated as working days. For the same period, the working-day count is always less than or equal to the calendar-day count, and long holidays such as Spring Festival or National Day can widen the gap by more than ten days.
Under China's Measures for Holidays of National Annual Festivals and Memorial Days, New Year's Day, Spring Festival, Qingming, Labour Day, Dragon Boat, Mid-Autumn and National Day are public holidays. The General Office of the State Council publishes the detailed arrangement for the following year each November, specifying both the holiday ranges and the weekends that become working days. Holiday data is therefore year-specific and cannot be derived by assuming the same dates every year.
Most construction and renovation contracts count the start date as day 1, so the completion date equals the start date plus the duration minus 1 day. Others count from the day after the start date. The two conventions differ by a full day even on short projects, so confirm which one applies; the "duration includes start date" switch lets you align the calculation with your contract.
When design changes, suspension for the client's reasons, force majeure or prolonged bad weather occur, the contractor may claim an extension under the contract, normally for the number of days actually affected. Extensions should be recorded in writing within the agreed period, otherwise a later claim may be weakened. The "extension" field adds the agreed number of days straight onto the completion date.
| Holiday | Dates | Days | Makeup working days |
|---|---|---|---|
| New Year's Day | Jan 1 (Thu) – Jan 3 (Sat) | 3 | Jan 4 (Sun) |
| Spring Festival | Feb 15 (Sun) – Feb 23 (Mon) | 9 | Feb 14, Feb 28 (Sat) |
| Qingming | Apr 4 (Sat) – Apr 6 (Mon) | 3 | None |
| Labour Day | May 1 (Fri) – May 5 (Tue) | 5 | May 9 (Sat) |
| Dragon Boat | Jun 19 (Fri) – Jun 21 (Sun) | 3 | None |
| Mid-Autumn | Sep 25 (Fri) – Sep 27 (Sun) | 3 | None |
| National Day | Oct 1 (Thu) – Oct 7 (Wed) | 7 | Sep 20 (Sun), Oct 10 (Sat) |
Source: General Office of the State Council, Notice on the Arrangement of Public Holidays in 2026.