The job
Their units. Your units.
The supplier quotes in one thing, you order in another, and the stock comes in a third. Somewhere in that chain is a sum you do on your phone in a car park, and the one time you get it wrong you are either short on site or sitting on stock you did not want.
A search engine will convert the units. It will not know your drums come in twenty-fives, that you allow ten percent for wastage, or that you always round up to the next full box.
What you get
The conversion you actually do.
Your pack sizes, not the textbook
Whatever the thing actually arrives in. The answer comes back in units you can order.
Your allowance is built in
Wastage, offcuts, the bit you always add. It is part of the sum rather than something to remember afterwards.
It rounds your way
Up to the next box, down to the nearest half, whatever you actually do. Rounding is where these go wrong.
Both directions
Theirs to yours and back again, because you need it both ways and always on the wrong side of the counter.
Who it suits
As right as the rule you give it.
This is a good fit for anyone ordering across a unit boundary: a supplier who thinks in one measure, a job that consumes another. A conversion is used and discarded, so nothing here needs keeping, which is exactly the shape of what we build.
The honest caution is different for this one. The tool will do your sum perfectly and it has no way of knowing whether your sum is right. If you tell it the wrong wastage figure it will apply the wrong wastage figure, quickly and consistently, forever. Check the first few against a job you already know.
Getting one
Describe it the way you explain it.
What comes in, what you need out, what the supplier calls it, and the adjustment you make that is not written down anywhere.
Usually about three minutes8 from that to a working tool you can open.