Like-for-Like Comparison Calculator

Two hundred and forty-eight thousand last period, two hundred and seventy-one thousand this one. Up nine and a quarter per cent.

Down five per cent once the rest comes out.

There was an eighteen thousand order that will not repeat, two extra trading days, and prices went up four per cent. All three put money in the top line without anything happening to the business, and all three are commoner than they sound. A comparison is only worth as much as its two halves are alike.

Each adjustment is shown separately and in turn — the one-off comes off in money, the trading days scale what is left, the price rise divides it — so somebody who disagrees with one of them can disagree with that one without throwing away the others. An argument about the price rise should not become an argument about everything.

The gap between the reported figure and the comparable one is fourteen and a quarter points, and that gap is the part of the headline that was not business.

It is entirely possible to adjust away a real change, and the page says so rather than selling the adjusted figure as the truth. If you strip out every good thing that happened as a one-off, you will produce a comparable figure showing that nothing ever improves. A one-off is something that will not repeat — not something that happened to go well — and that distinction is a judgement the page cannot make for you.

The price adjustment assumes the rise stuck. If you put prices up and lost volume because of it, that lost volume is a real result, and dividing it out would hide the very thing you wanted to know.

None of this is pessimism. It is what has to happen before two periods are answering the same question.

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. Two comparisons side by side is how a run of adjusted figures becomes a trend rather than an argument.

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.