That is four columns and 2 formulas surely

I thought that... You could have written one in the time it took to post!

I used this one:

Why re-invent what you can re-use? That looks comprehensive, thx Alex.

laziness

I used a thing called a pen and something called paper.. Worked for me.

I used a thing called a pen and something called paper

No I couldn't find the links unfortunately.. Try raking in a drawer at home or robbing some scrap paper from work. I think I may have even seen paper stacked up and bound together in a "notepad" (I think the shop assistant called it that) for sale in shops.

I've got an old envelope, some space on the back

This is a serious document - not to be taken lightly. 😉

You need rows for components, then columns for item, cost, weight (if necessary), colour, source, lead time, received. Then you need options for the above, where you balance out better wheels v groupset spec level etc. All this give a gross cost.

Then, most importantly, you need a selling list with predicted and actual sale prices to knock off the gross cost of the above giving a predicted net cost that is far below the actual.

You present the predicted net cost to the approving authority and congratulate yourself on the frugality of your new build. 🙂

pm me. I have one I've used in the past. You just input the various component options and prices then you can tweak the build accordingly.

I used a thing called a pen and something called paper.. Worked for me.

"laziness" or efficiency? Or simply lacking the hubris to think I can do a better job than someone who has already done it 😉

pm me if you want mine.

Yak has it right. I had a spreadsheet very similar to that. Thankfully the selling section was never properly audited 🙂

Don't forget the columns for upgrades (weight/cost/difference) before you've even finished the build.