Building a box calculator?

[Gaogier]

Hello

Please note, I am autistic and things that seem simple never are for my brain. Where my knowledge, especially maths, sciences, technology, history, geography etc is questioned by my brain into either overthinking or convincing myself that the answer is wrong, even if it is correct.

I need to build a simple wooden box, that I will get the store to cut down for me, I can do it but if it saves me a couple of days (I am also disabled and would need to wait for a good day with mobility and pain, where I won’t take any morphine is not predictable.

Anyway, a simple box I fully understand but what about the thickness of the wood, that will need to be calculated into correct?

Example.

A box with that is 200mm x 400mm x 600mm. I would need 2, 200mm x 400mm, 2 200mm x 600mm and 2 400mm x 600mm however if the thickness of wood is calculated into the same box, with 18mm thick, wouldn’t I need 2 200mm x 382mm 2 200mm x 582mm and 2 382mm x 582mm

Could someone please just confirm my thinking here, and if so, do you know of a simple way to calculate all of this? Even an online free calculator would be helpful.

Thank you.

 

[Alec_t]

It rather depends on how you want to assemble the pieces. Your second set of figures is correct if you assemble the pieces as in Figre A below, but would differ if you assembled them as in Figure B.

 

[foxhole]

Buy a box .

 

[Harry Bloomfield]

It rather depends on how you want to assemble the pieces. Your second set of figures is correct if you assemble the pieces as in Figre A below, but would differ if you assembled them as in Figure B.

It might differ again depending if the box measurements are intended to be internal, or external.

 

[big-all]

Simplest way to do it is 2 sides and the base identical widths so one pass 3 components
plan the sides to be full height and screwed sideways into the base
you now take the height from the sides to cut off
you can actually do it from only 3 moves off the fence on a table saw

first action ,,,,,,,move fence too width two ends and base cut to width
second action..........move fence .....to required height ,,,ends cut off the base section both ends iff cut as one ...and 2 sides cut to height
assemble base and ends...... measure outer size ..... this is the third fence set up and cuts the sides to length

you can cut the components a bit oversized and individual iff easier then just pass 3 though first pass [ends and base ]
then 4 through second pass [all sides] then 3rd pass 2 through last pass[ 2 sides to length]

much much easier to cut at home than trying to get accurate in store cutting assuming your table saw has the inside width capacity [blade to fence]