business-rules.md

Business rules

SlaCalculator allows an SLA to follow the actual working rules of an organization.

Business rules are only applied when:

UseBusinessHoursOnly = true

Otherwise, the SLA uses wall-clock time.

Business hours

Business hours define the portion of each business day that can contribute to the SLA.

For example:

BusinessHoursStart = TimeSpan.FromHours(9);
BusinessHoursEnd = TimeSpan.FromHours(17);

This gives 8 applicable hours per business day.

A task started at 16:00 with a 4-hour SLA would have:

• Day 1: 16:00 → 17:00 1 hour
• Day 2: 09:00 → 12:00 3 hours

The deadline is therefore 12:00 on the following business day.

Business days

BusinessDays determines which days are eligible to contribute time.

For example, a Monday–Thursday schedule:

BusinessDays = new List<DayOfWeek>
{
    DayOfWeek.Monday,
    DayOfWeek.Tuesday,
    DayOfWeek.Wednesday,
    DayOfWeek.Thursday
};

Friday is not considered a business day even though it would normally be part of a Monday–Friday schedule.

Holidays

Holidays are additional exclusions.

For example:

Holidays = new List<DateTime>
{
    new DateTime(2026, 9, 7)
};

If September 7 is a Monday, it will not contribute business time even if Monday is included in BusinessDays.

Business Days and Holidays Together

The two settings are independent. For example:

BusinessDays = new List<DayOfWeek>
{
    DayOfWeek.Monday,
    DayOfWeek.Tuesday,
    DayOfWeek.Wednesday,
    DayOfWeek.Thursday
};

Holidays = new List<DateTime>
{
    new DateTime(2026, 9, 7)
};

This means:

• Monday is normally a business day, but September 7 is a holiday.
• Tuesday–Thursday are business days.
• Friday is not a business day.
• Saturday and Sunday are not business days.

Example: SLA spanning a weekend and holiday

Consider:

• Business hours: 09:00–17:00
• Business days: Monday–Friday
• Friday: holiday
• Monday: holiday
• Saturday/Sunday: weekend
• SLA starts Thursday at 09:00
• SLA duration: 15 hours

The calculation is:

• Thursday 09:00 → 17:00 8 hours
• Friday holiday
• Saturday weekend
• Sunday weekend
• Monday holiday
• Tuesday 09:00 → 16:00 7 hours

Total: 15 hours → deadline Tuesday at 16:00.

Custom working schedules

The library does not require a Monday–Friday schedule. For example, a business operating Tuesday–Saturday can configure:

BusinessDays = new List<DayOfWeek>
{
    DayOfWeek.Tuesday,
    DayOfWeek.Wednesday,
    DayOfWeek.Thursday,
    DayOfWeek.Friday,
    DayOfWeek.Saturday
};

Similarly, a support team operating 24 hours but only on weekdays could use:

BusinessHoursStart = TimeSpan.Zero;
BusinessHoursEnd = TimeSpan.FromHours(24);

BusinessDays = new List<DayOfWeek>
{
    DayOfWeek.Monday,
    DayOfWeek.Tuesday,
    DayOfWeek.Wednesday,
    DayOfWeek.Thursday,
    DayOfWeek.Friday
};

Wall-clock vs business time

There are two fundamentally different SLA models.

Wall-clock (UseBusinessHoursOnly = false):

The SLA continuously counts elapsed time.

• Monday 16:00 + 4 hours = Monday 20:00

Business time (UseBusinessHoursOnly = true):

Only configured business time counts.

• Monday 16:00 → 17:00 = 1 hour
• Tuesday 09:00 → 12:00 = 3 hours

Deadline = Tuesday 12:00

This distinction allows the same calculator to support both 24/7 and business-hours-based service agreements.