bizdurr

A lightweight, flexible business duration calculator

Calculate the amount of time that falls within your defined business hours — accounting for weekly schedules, holidays, and per-date overrides.

Installation

uv add bizdurr

Or with pip:

pip install bizdurr

Or install from source:

git clone https://github.com/patclrk/bizdurr.git
cd bizdurr
uv pip install .

Quick Start

from datetime import datetime
from bizdurr import BusinessDuration

# Define your weekly business hours
schedule = {
    "monday":    {"start": "09:00", "end": "17:00"},
    "tuesday":   {"start": "09:00", "end": "17:00"},
    "wednesday": {"start": "09:00", "end": "17:00"},
    "thursday":  {"start": "09:00", "end": "17:00"},
    "friday":    {"start": "09:00", "end": "17:00"},
}

# Create a BusinessDuration instance
bd = BusinessDuration(
    business_hours=schedule,
    business_timezone="America/New_York",
)

# Calculate the business duration between two datetimes
start = datetime(2025, 12, 8, 8, 0)   # Monday 8:00 AM
end   = datetime(2025, 12, 8, 18, 0)  # Monday 6:00 PM

duration = bd.calculate(start, end)
print(duration)  # 8:00:00 (8 hours of business time)
type(duration)  # <class 'datetime.timedelta'>

Features

Weekly Schedule

Pass a dict mapping weekday names (case-insensitive) to start/end times in HH:MM 24-hour format:

schedule = {
    "monday": {"start": "09:00", "end": "17:00"},
    "tuesday": {"start": "10:00", "end": "16:00"},
    # ...
}

Shorthand Schedule (Monday–Friday)

For a fixed Monday through Friday schedule, use the shorthand format:

bd = BusinessDuration(
    business_hours={"start": "09:00", "end": "17:00"},  # Expands to Mon-Fri
    business_timezone="America/New_York",
)

This automatically expands to Monday through Friday with the same hours. Weekend days (Saturday and Sunday) are excluded.

Holidays

Exclude specific dates from business hours:

bd = BusinessDuration(
    business_hours=schedule,
    business_timezone="America/New_York",
    holidays=["2025-12-25", "2026-01-01"],  # ISO date strings or date objects
)

Per-Date Overrides

Override business hours for specific dates (e.g., early close):

bd = BusinessDuration(
    business_hours=schedule,
    business_timezone="America/New_York",
    overrides={
        # Christmas Eve: half day
        "2025-12-24": {"start": "09:00", "end": "12:00"},
    },
)

Timezone Handling

The business_timezone parameter specifies where the business is located. All business hours are interpreted in this timezone, and all calculations are performed relative to it.

from datetime import datetime
from zoneinfo import ZoneInfo
from bizdurr import BusinessDuration

# Business is located in New York
bd = BusinessDuration(
    business_hours={"start": "09:00", "end": "17:00"},
    business_timezone="America/New_York",
)

# 1. Naive datetimes are assumed to be in the business timezone
bd.calculate(
    datetime(2025, 12, 8, 10, 0),
    datetime(2025, 12, 8, 15, 0)
)  # 5 hours

# 2. Aware datetimes in the same timezone work as expected
eastern = ZoneInfo("America/New_York")
bd.calculate(
    datetime(2025, 12, 8, 10, 0, tzinfo=eastern),
    datetime(2025, 12, 8, 15, 0, tzinfo=eastern)
)  # 5 hours

# 3. Aware datetimes in different timezones are converted automatically
pacific = ZoneInfo("America/Los_Angeles")
bd.calculate(
    datetime(2025, 12, 8, 7, 0, tzinfo=pacific),   # 7 AM Pacific = 10 AM Eastern
    datetime(2025, 12, 8, 12, 0, tzinfo=pacific)   # 12 PM Pacific = 3 PM Eastern
)  # 5 hours