Contract deadline calculator

Work out notice periods, payment due dates, renewal dates and response deadlines. Month arithmetic stops at month end, so January 31 plus one month is the last day of February.

Start date

Number

Unit

Direction

Holidays to skip for business days (optional, one date per line or comma-separated, YYYY-MM-DD)

Things to check

Is the start day counted? This calculator counts from the day after the start date, which is the usual rule, but some contracts and courts say otherwise.
Weekends and holidays. Many rules move a deadline that falls on a non-business day to the next business day.
Time zones and cut-off times. "By 5pm" or "close of business" matters for filings and notices.

A calculation aid, not legal advice. Court and statutory deadlines follow their own rules.

Clausery templates can calculate these dates for you with add_days, add_months and add_years.

Add this calculator to your website

Free for blogs, accountants, law firms, trade associations and anyone who helps small businesses. Paste the code where you want the calculator to appear. It runs in your visitors' browsers, with no cookies, no tracking, and nothing they type sent anywhere.

Embed code

<iframe src="https://getclausery.github.io/free-tools/embed/deadline-calculator.html" title="Contract deadline calculator" width="100%" height="570" style="border:0;max-width:760px" loading="lazy" allow="clipboard-write"></iframe>
<p style="font-size:13px;margin:4px 0 16px">Contract deadline calculator by <a href="https://getclausery.github.io/free-tools/deadline-calculator.html">Clausery</a></p>
<script>window.addEventListener('message',function(e){if(e.origin!=='https://getclausery.github.io'||!e.data||!e.data.clauseryHeight)return;var f=document.getElementsByTagName('iframe');for(var i=0;i<f.length;i++)if(f[i].contentWindow===e.source)f[i].style.height=e.data.clauseryHeight+'px';});</script>

Preview

The last line of the code resizes the calculator to fit; if your site strips scripts, leave it out and the calculator still works at a fixed height. On a dark website, add ?theme=dark after deadline-calculator.html. Please keep the credit line under the calculator.

Questions

How do you count days for a contract deadline?

The usual convention, used by this calculator, is to exclude the start day and count from the next day, so 10 days from 1 March is 11 March. Some contracts and court rules also move a deadline that falls on a weekend or holiday to the next business day; check the wording that applies to you.

What happens when adding months to the end of a month?

If the target month is shorter, the date moves to its last day, so one month after 31 January is 28 February (29 in a leap year).

What counts as a business day?

Monday to Friday, excluding any holidays you enter. Public holidays differ by country and state, so add the ones that apply to your contract.

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