Writing Deadlines in Working Days Without Starting an Argument
By Mohak Mangal · Published October 26, 2026 · 6 min read
Most arguments about deadlines aren't about effort. They're about arithmetic nobody agreed on. One side counts from today, the other from tomorrow. One treats Saturday as a working day, the other doesn't. Both are sure they're right, and in a way they both are.
You can avoid nearly all of it with a few sentences of precision.
The five questions every deadline should answer
- When does the clock start? On the day the request is received, or the next working day? What if it arrives after a cut-off time, say 5 p.m.?
- Does that first day count as day one?
- Which days are non-working? Saturday and Sunday, Friday and Saturday, Sunday only?
- Whose holidays count? The supplier's, the customer's, or the national list of one specific country?
- What time of day does the deadline end? Midnight in whose time zone?
If you can answer all five in a sentence, you're unlikely to need a lawyer for the next part.
Three examples of vague vs clear
Vague: "We will respond within 3 days."
Clear: "We will respond within 3 business days of receiving your request, excluding Saturdays, Sundays and public holidays in Karnataka, India. Requests received after 5:00 p.m. IST are treated as received the next business day."
Vague: "Payment due in 30 days."
Clear: "Payment is due 30 calendar days after the invoice date shown on the invoice."
Vague: "Delivery in 5-7 working days."
Clear: "Orders placed before 2 p.m. IST on a business day ship the same day. Delivery typically takes 5-7 business days after shipping."
Calendar days vs business days: pick one on purpose
Thirty calendar days is about four and a half weeks. Thirty business days is about six weeks, and with a few public holidays it can run nearer seven. If you mean one and write the other, you've changed the deadline by two weeks without noticing. Use calendar days for things that don't depend on offices being open (a subscription period) and business days for things that do (a human review).
Holidays are the hardest part
Official holiday lists differ by country, state and sometimes industry. Some dates move each year. Banks can have their own closure days. The sturdy approach is to reference a named, published list ("the central government's list of gazetted holidays for that year") or to give explicit dates in the document. If you can, attach the dates.
Weekend rules vary
If a counterparty is in a region where the weekend is Friday and Saturday, a clause that quietly assumes Saturday-Sunday will give them three-day weekends and a one-day disagreement. Name the days.
State the resulting date when you can
The most effective sentence in any deadline is the last one: "...which makes the due date Thursday, 14 January 2027." A date can't be misread. If the stated date and the stated rule ever disagree, you at least know exactly where the confusion is.
Calculate it, don't guess it
Counting on a calendar by hand is where errors creep in, especially across month boundaries and holidays. The business days calculator lets you choose the weekend pattern, paste your holiday list, and either count days between two dates or add working days to a start date. Use it when you draft the clause, and again when you check that the final date matches the wording.
This is general information, not legal advice. For contracts with real stakes, have a qualified professional review the wording.