There are many ways to hang pictures depending on fastening methods available, personal preferences, tools and equipment etc. These can range from simple arbitrary placement, use of centerlines, center points or edges; and may use simple tools like a spirit level and tape measure, or precision location using lasers. All are perfectly valid methods.
If you consult YouTube or an AI Chatbot, chances are you will get complicated instructions often involving lots of painter's tape and placing mock-up layouts on the wall. I think these are often unnecessary and wasteful.
The approach I prefer is to simply lay the works out in front of the wall, or on the floor, then arrange and rearrange until the set feels right. Maybe so that no one piece dominates and there is an appealing distribution of content, colors and tones etc. After that, do a sketch on paper with key parameters, like alignment heights, inter-work and end spaces. These will set the framework. As a reference the center point (mid-line alignment height) is generally suggested to be 57 inches or 1450 mm high. Spacing between works will be closer in clustered works - perhaps 3 inches or 80 mm, but wider to expansive layouts. Centerline and other key positions are useful to mark on the wall with tape, eg. to mark golden ratio positions (eg. with scratchpad calculator's length/phi
) etc.
Then measure the works. Three or four measurements may be needed for each artwork:
Armed with these measurements, use the calculator to determine fastener positions. Other distances used for positioning: vertical height on wall; horizontal inter-work or first/end spacing (ie. to previous edge); and, vertical inter-work spacing for a vertical group.
All this can be done without sticking mock-ups on the wall. Painters tape is super useful for marking start and end points, reference heights, and center points. But, there is no need to cover a wall with it. All the work can be done with a pencil, tape measure and spirit level (ideally one with a measurement scale on it).
I hope the calculators can be used to make relevant and helpful calculations for your purposes.