Product Mix and Bottleneck Calculator

Three products. One makes 60% margin, one makes 50%, one makes 45%. Everybody knows which to push.

Now add the oven. The 60% product takes eight hours and earns $30 an oven hour. The 50% one takes one hour and earns $60. The ranking is not just different, it is reversed at the top — and on the figures this ships with, filling the oven with the best-margin product earns $4,800 while the honest plan earns $11,250 from exactly the same hours.

That is the whole product. Margin percentage is the right ranking when nothing is short. The moment one machine, one oven, one person or one licence is the limit, the right ranking is contribution per unit of THAT, and almost nobody switches.

The page fills the constraint for you, best use first, and tells you how much of each to make and how much demand you will have to turn away. With one constraint and demand you can take part of, that greedy plan is not an approximation — it is provably the best possible answer, which is the one genuinely tidy result in this subject.

It also says when nothing is actually scarce. If all the demand you have listed fits in the capacity you have, there is no allocation problem and the page says so rather than manufacturing a finding.

One constraint at a time. If two things are short at once this will hand you a plan that breaks the other one, and the page says that rather than pretending otherwise.

And it does not tell you to drop anything. A product making nothing in this plan may be the reason customers come at all, and dropping it does not drop its share of the fixed costs — those stay exactly where they are and get spread over less. This ranks. It does not decide.

Save as many versions as you like and put any two side by side, figure against figure, with the better one on each line marked and the difference in its own column. That screen is the one that decides things, and it is the part a free calculator cannot do at all. What is scarce changes with the season, and so does the answer.

One HTML file. No account, no subscription, no internet needed. Opens on Windows, Mac and Android; the readme explains the extra step on iPhone and iPad, where Apple blocks JavaScript in downloaded files and every tool of this kind is affected.

Everything lives in your browser on your device. Nothing is uploaded, which is why it works offline and why nobody else can see your figures — and it also means clearing your browsing data deletes it. The tool does not pretend otherwise: the header shows how long since your last export at all times, turns amber after three days and red after seven, and export is one click that produces a plain file you keep.