The right size mostly depends on your space and preference. If you have a large empty wall, maybe adding in a big calendar will bring everything together. If you’re getting the calendar for your desk, then a smaller one is usually the better option, to ensure you don’t crowd your workspace too much. However, a smaller calendar has the downside of having a limited area for writing, so if you’re someone who makes a lot of notes and reminders for your day, then perhaps the big wall calendar is the best fit for you.