The calculation of time is important because it determines when deadlines begin and expire and when various legal consequences arise (e.g., limitation periods, preclusion, maturity of claims, etc.).

There are several types of deadline:

• imperative, strict deadlines – a legal transaction cannot stipulate a longer or shorter deadline than the one prescribed by law (e.g., limitation periods, preclusive deadlines);
• dispositive deadlines – deadlines prescribed by law, but allowing the parties to agree otherwise regarding the passage of time (an example of dispositive time calculation is Article 62(4) of the Obligations Code, which states that the beginning of the month means the first day of the month, the middle the fifteenth, and the end the last day of the month);
• deadlines set by the parties to a legal transaction – these deadlines must be set clearly and unambiguously.¹³⁹

Fundamental rules for counting deadlines:

a) Beginning of the deadline
Starting day. The deadline begins the day after the event that triggers the deadline (e.g., contract conclusion, receipt of a submission, etc.).
The first day does not count. The first day when the event occurs is not included in the deadline (unless otherwise specified).
b) Duration of the deadline
Fixed deadline. The deadline is expressed in days, weeks, months, or years, depending on how it is set. A deadline set in weeks, months, or years ends on the day that corresponds in name and number to the day the triggering event occurred. If such a day does not exist in the final month, the deadline expires on the last day of that month.¹⁴⁰
Fixed time. If the deadline is set in days, it is counted by calendar days, not by working days or holidays.
c) Calculation of the final day
Last day of the deadline. The deadline expires at the end of the day specified (e.g., at midnight or 24:00).
Holidays and Sundays. If the last day of the deadline falls on a holiday or Sunday, the deadline is extended to the next working day.
d) Setting deadlines in contracts
Parties can agree in a contract on the determination of the deadline for fulfilling obligations. This deadline must be set clearly and unambiguously to avoid potential disputes.¹⁴¹

Example: A and B enter into a contract on 3 March 2012, stipulating that A will deliver 60 towels for B’s hotel within 30 days of the contract signing. The deadline starts on 4 March 2012 and runs until 2 April 2012.

Example: A and B enter into a contract on 3 March 2012, stipulating that A will deliver 60 towels for B’s hotel within one month from the date of the contract signing. The deadline starts on 4 March 2012 and runs until 4 April 2012.

Example: A and B enter into a contract on 31 January 2012, stipulating that A will deliver 60 towels for B’s hotel within 30 days of the contract signing. The deadline starts on 1 February 2012 and runs until 1 March 2012.

Exercise:

1. Mike and Veronica agreed on Friday, 30 April 2010, that Mike must fulfil the contract within one month. Using the following calendar as a reference: Monday, 24 May 2010; Tuesday, 25 May 2010; Wednesday, 26 May 2010; Thursday, 27 May 2010; Friday, 28 May 2010; Saturday, 29 May 2010; Sunday, 30 May 2010; Monday, 31 May 2010; Tuesday, 1 June 2010.

Indicate the date by which Mike must fulfil the contract!¹⁴²

2. Heather’s grandfather lent her money on Saturday, 2 May 2015, for two years.

By what date must she return it?