Date Add / Subtract Calculator
About Calendar Generator
The Universal Customizable Calendar Generator creates printable, exportable monthly and yearly calendars with custom start days (Sunday vs. Monday), highlighted event markers, week numbers (ISO-8601), and CSV/PDF/HTML export options.
How to Use Calendar Generator
Step 1
Select Month and Year.
Step 2
Choose Week Start day (Sunday or Monday) and toggle ISO week numbers.
Step 3
Optionally add highlighted event dates.
Step 4
Click "Print Calendar" or "Copy Text Grid".
Practical Use Cases for Calendar Generator
Custom Printable Desk & Wall Calendar Creation
Generate clean, printable high-resolution monthly and yearly calendars with custom branding, notes areas, and marked holidays.
Project Schedule & Team Shift Rotation Visualization
Generate visual monthly grid calendars highlighting team on-call rotations, release sprints, and corporate holidays.
Input & Output Examples
Generating Calendar for October 2026 (Monday Start)
Month: `October 2026`, Week Start: `Monday`, ISO Weeks: `Enabled`
Grid: `31 Days` | Weeks 40-44 | First Day: `Thursday, Oct 1` | Last Day: `Saturday, Oct 31` | Weekends: `9 days`
Key Features & Performance
- ✓Custom Week Start Day: toggle Sunday start (US standard) or Monday start (ISO-8601 / European standard).
- ✓Export Formats: 1-Click Print (CSS Print Optimized), Plain Text ASCII Grid, CSV, and HTML snippet.
- ✓Highlight Custom Dates: mark birthdays, deadlines, and project milestones directly on the grid.
- ✓100% Client-Side calendar rendering.
- ✓1-Click Copy or Download generated calendar.
Key Terminology & Definitions
ISO-8601 Week Start
The international standard specifying that Monday is the first day of the week and that Week 1 is the week containing the first Thursday of the year.
Perpetual Grid Matrix
A 7-column calendar grid displaying days of the month aligned to their respective weekdays.