Choosing the right size for your countertop clear acrylic magnetic photo frames based on the size of your photos involves a few simple steps:

1. Measure Your Photos: Start by measuring the dimensions of your photos in inches or centimeters. It's important to note both the length and the width.

2. Standard Sizes: Familiarize yourself with standard photo sizes. Common sizes include 4x6 inches, 5x7 inches, and 8x10 inches, among others. These sizes often correspond to the dimensions of the photo frames available in the market.

3. Match Frame to Photo: Select a frame size that matches or is slightly larger than your photo. If the frame is larger, you may need to consider adding a mat or spacer to ensure the photo fits snugly within the frame.

4. Consider the Display Area: Think about where you plan to display the photo. The size of the frame should complement the space without overwhelming it. For a countertop, a smaller frame may be more suitable to avoid clutter.

5. Check Frame Dimensions: When shopping for frames, pay attention to the internal dimensions, which should be listed in the product specifications. These are the dimensions of the area that will hold the photo.

6. Magnet Placement: Since these are magnetic frames, consider how you will be using the magnet feature. Will it be on a refrigerator, a filing cabinet, or another magnetic surface? The size of the frame should be manageable for the intended use.

7. Visual Balance: Ensure that the frame size creates a visual balance with the photo. A frame that is too large or too small can detract from the photo's impact.

8. Future-Proofing: If you plan to print more photos in the future, you might want to consider a frame size that is versatile and can accommodate different photo sizes.

9. Online Tools: Some retailers offer online tools that allow you to upload a photo and see how it would look in different frame sizes.

10. Trial and Error: If possible, try placing your photo in different sized frames to see which size best suits your aesthetic preference.

By following these steps, you can ensure that you choose the right size for your countertop clear acrylic magnetic photo frames that will beautifully showcase your photos while fitting comfortably in your space.