It’s possible to experience Bryce Canyon National Park in just a day, including a hike into the amphitheater to spend a few hours among the hoodoos, walk a segment of the rim trail, and perhaps have lunch in the Lodge at Bryce Canyon.
Three to 4 days, however, will provide plenty of time to explore most of the park (except the backcountry), including hiking the length of the Rim Trail, biking the Shared-Use Path, and taking the various trails through the amphitheater. Spending the night at the Lodge is highly recommended for its convenience and history; it’s the best way to ensure an early arrival to watch the sun come up at nearby Sunrise Point, for example. A multi-day visit will also allow visitors the opportunity to drive the southern section of the park road and make stops for additional hikes, and venture to the more distant Fairyland and Mossy Cave areas of the park.