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Business Day Calculator

Subtract Business Days from a Date

Use this calculator when a deadline is fixed and you need to know the latest day to start to deliver on time. Enter the end date, the working-day duration of the prep work, and the holiday calendar; the result is the latest start date that still hits the deadline.

A worked example: a federal grant proposal is due to grants.gov by 11:59pm Eastern on Friday, October 30, 2026. The internal sign-off pipeline at the principal investigator's university takes 15 business days end to end (legal review, finance review, dean approval, sponsored programs office submission). Subtracting 15 business days from October 30 under the US calendar lands at Friday, October 9, 2026, which is the latest the principal investigator can hand the draft to the sponsored programs office. The same backward-counting logic applies to bid submissions under FAR Part 15, regulatory comment periods, audit finding remediation deadlines, clinical-trial site activation timelines, and any other contractual deadline where the prep work has to fit inside a working-day envelope.

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Common calculations: business days ago

5 business days ago7 business days ago10 business days ago14 business days ago15 business days ago20 business days ago21 business days ago25 business days ago28 business days ago30 business days ago45 business days ago60 business days ago90 business days ago100 business days ago120 business days ago

For informational purposes only

This calculator provides general estimates based on business day counting rules. It does not constitute legal advice. Deadlines in legal, regulatory, or contractual matters may be subject to jurisdiction-specific rules, court orders, or statutory exceptions. Always verify critical deadlines with a qualified professional.

Frequently Asked Questions

How do I find the latest start date for a fixed deadline?
Enter the deadline date in the end-date field, then enter the working-day duration of the prep work in the days field. The calculator subtracts the working days, skipping weekends and your country's public holidays, and returns the latest day to start. A grant proposal due Friday October 30, 2026 with a 15-business-day internal review needs to be in the review committee's hands no later than Friday October 9, 2026 under the US calendar.
How is this different from the Business Days Ago calculator?
Subtracting business days lets you choose any deadline date, which is the right tool for back-planning from a fixed contract or regulatory date. Business Days Ago uses today's date as the anchor, which is the right tool when you need to know what working day fell N days back from now (e.g., for service-of-process or notice-of-claim windows that started in the past).
Can I use this for press release embargo dates?
Yes. A common workflow: a press release is embargoed until a public launch date set five business days from the editorial cutoff. Subtract 5 business days from the launch date to find the latest internal sign-off deadline. Wire-service embargoes (Business Wire, PR Newswire, Reuters Connect) all run on working-day calendars in the country of release, and the same math applies whether the launch is on a Monday in New York or a Tuesday in Tokyo.
What happens to the start date if the deadline shifts by a week?
Re-enter the new deadline and the calculator recomputes the start date with the same working-day duration. The new start date will rarely shift by exactly seven calendar days because the recomputation has to skip whichever weekends and holidays fall in the new window. A one-week deadline slip can move the start date by five to nine calendar days depending on where holidays land.
How does subtracting business days handle observed holidays?
Observed-day shifts are baked into the country's holiday data. When Independence Day falls on a Saturday, for example, the federal observance moves to Friday, and the calculator treats that Friday as the closure day rather than the literal Saturday. Subtraction across the observed Friday is therefore correct without any manual adjustment.