A price rise and a fall in purchasing power are not the same number. This is the thing almost every inflation figure gets wrong, and it is what this page is built around.
If prices double, they have risen 100% — and your money now buys half as much, a fall of 50%. Not 100%. A hundred per cent fall in purchasing power would mean your money buys nothing whatsoever. The two figures are reciprocals, not opposites, and they diverge enormously over long periods: prices up 900% is a 90% loss, not a 900% one.
There are also two directions, and people mean both by "what is my money worth now". What you would need today to buy what a past sum bought is one answer. What that same sum, still in your pocket, buys today is the other. Both are on this page, because answering only one leaves half of readers with the wrong figure.
Inflation compounds. 5% a year for twenty years is 165%, not 100% — each year's rise is charged on the year before it. The linear reading is shown beside the real one so the gap is a figure rather than a warning.
This uses a rate you choose, not a published index. PRD-wise the tool has two possible modes and only one is built: a proper historical answer needs the published consumer price index as a versioned dataset, and this site does not hold one yet. A series typed from memory would produce a confident, wrong history of the peso — so the honest mode ships and the other waits.
No — it lost about 62%. A price rise and a fall in purchasing power are not the same number, and this is the mistake the tool exists to prevent. They are reciprocals, not opposites: if prices double they have risen 100%, and your money buys half as much, which is a fall of 50%. However far prices climb you can never lose more than 100% of what your money buys, because that would mean it buys nothing at all.
Because people mean two different things by "what is my money worth now". One is what you would need today to buy what a past sum bought — that is the big figure. The other is what that same sum, still in your pocket, buys today. They are opposite directions and both are shown, because answering only one of them leaves half of readers with the wrong number.
No, it means 165%. Inflation compounds — each year’s rise is charged on the year before it, not on the original amount. Over short periods the difference is small; over twenty years the linear reading understates the result by about a third, and over forty it is not close. The page shows both figures so the gap is visible.
No, and that is deliberate. It applies one average rate that you choose, evenly across the whole period. A proper historical answer needs the published consumer price index, and that is a versioned dataset this site does not yet hold — a CPI series typed from memory would produce a confident, wrong history of the peso. Use the calculator for "what if" questions, and the PSA’s published index for historical fact.
That is your assumption to make, which is why the field is labelled one. For a forward-looking question many people use the central bank’s target band as a starting point; for a backward-looking one the actual average over your period is what you want, and it may be very different. Try a range rather than a single figure — the spread between 3% and 6% over twenty years is large, and seeing it is more useful than one confident number.
Yes. Put the later year in "From" and the earlier one in "To" and it deflates instead of inflating. The answer is the exact mirror of running it the other way round.
Enter a negative rate. Prices falling means the same money buys more, so purchasing power rises. The one thing refused is −100% or beyond, which would put prices at zero.
The last two lines are reciprocals of one another, which is why they never add to zero.
165% and 62% describe the same twenty years.Reading the price rise as the loss would overstate it by more than two and a half times. And the linear reading — 5% × 20 — gives ₱2,000, understating the real ₱2,653.30 by ₱653.30.
This applies one average rate that you choose, spread evenly across the period. It uses no published price index, so it answers 'what if' questions rather than historical fact. Real inflation moves year by year and differs by what you actually buy. Nothing you type here is sent to our servers — the calculation runs entirely in your browser.
