There is an option to make your design look smaller or larger on the artboard depending on your needs. We use proportional scaling that is why formats with different resolutions look all the same on the artboard. This is why you need to pay attention to the number on the scale- for instance, if it is 200%, it means that you need to decrease the scale to 100% to preview the actual size of the design and how it will look after exporting from Crello.
When you work on a Business card design, there is a 280% scaling by the default- click on the scale to adjust the percentage to 100% and you will see how the image will look when printed out:
See the difference in size:
Image 1 enlarged to 280% of the initial size:
Image 2- the actual size of the card when the scale is set to 100%:
The same applies to the formats that have a larger res and need to fit onto the artboard and there is a smaller scaling used in such cases: