The job
The sum you do every single day.
Dose by weight. Chemical by area. Load by axle. Yield by tray. Margin by cost. Different trades, same problem: a calculation you have done a thousand times, still done in your head, still occasionally wrong.
The cost is not the arithmetic. It is the second-guessing, and the one time in fifty you get it wrong and only find out later.
What you get
The same answer, every time.
Your inputs, your names for them
Not generic fields. If you think in trays and bands, it asks for trays and bands.
It shows the working
So you can sanity-check it against what you already know, and trust it on the day you are tired.
Your rounding, your safety margin
The bits you would never write down but always apply. Say them once and they are baked in.
Everyone gets the same number
Whoever is on shift. The judgement stops living in one person’s head.
Who it suits
Anyone whose answer gets used and forgotten.
This is the best fit we build. You need the number now, you act on it, and the number itself does not need keeping. The tool computes and stops there, which is exactly the shape of the job.
If the calculation has to be filed, audited, or pulled up again in six months against a customer record, that is not this. The tool lives in the browser it was made in, so it is a calculator you trust rather than a record you keep.
Getting one
Describe the sum out loud.
The way you would teach it to someone on their first week. What goes in, what you multiply, where you round, and the bit you always add on that is not written anywhere.
Usually about three minutes8 from that to a working tool you can open.