AI Calculator — Ask a Calculation in Plain English

Type the sum the way you would say it — "15% of 240", "20% off 85", "5 km in miles" — and the answer appears straight away, with the working underneath and a link to the calculator that does the same job in more depth. No sign-up, no cost, and nothing you type is stored.

What It Understands

This is the whole of it. Each line is a calculation the page knows how to do, and anything outside the list gets a straight admission rather than an invented answer.

Where the Number Actually Comes From

There is a split inside this page, and it is the whole reason the figure can be trusted. Reading a question is one job. Working out the answer is a completely different one. They are never done by the same thing here.

The arithmetic is never handed to anything that predicts text. Models that write fluent sentences are fluent, confident and occasionally wrong about 17 × 23, and a wrong answer that looks exactly like a right one is more dangerous than no answer at all. Every number below the line on this page comes out of the same expression parser that runs the calculator on our homepage. It either knows the sum exactly or it admits it does not.

Understanding the sentence is the part where being clever costs nothing, because a misreading cannot hide. The working is printed under every answer. Ask for 15% of 240 and the 0.15 and the 240 are there in plain sight. Checking that it understood you takes about a second. That is the point of showing it.

Why Asking in Words Beats Hunting for the Right Calculator

Most people do not arrive knowing that the thing they want is called a reverse percentage. They know they paid £180 and £30 of it was VAT, and they want to know what the shirt cost. Somewhere between those two sentences is a menu of forty tools, and the honest truth about calculator websites is that the menu is where most visits end.

Typing the question in your own words skips all of that. You do not need the name of the operation, or the order the numbers go in, or to know whether you want an increase or the reverse of a decrease. You describe the situation. The page works out which calculation that is and does it, then points you at the dedicated tool if you want to change the numbers and watch the answer move.

The Questions People Actually Bring Here

These are not invented examples. They are the shapes of question the page was built around — phrased the way people type them, including the ones with no formula name attached. Every line below answers exactly as written; nothing here is an illustration of something you would have to rephrase.

Standing in a shop

Sale maths is the most common reason anyone opens a calculator on a phone, and it is also where the mental shortcut most often fails — 20% off then a further 10% off is not 30% off.

• 20% off 85
• 59.99 less 20%
• what is 15 percent of 240
• 240 reduced by 15%

Looking at a payslip or an invoice

VAT is the one that catches people out in both directions. Adding it to a net figure and pulling it back out of a gross one are different sums, and the second is not 20% of the price you paid.

• add VAT to 150
• remove VAT from 180
• my pay went from 50,000 to 62,000
• what percent is 30 of 120

At the end of a meal

The bill split with a tip on top is four operations deep and everyone does it at the table with a phone in one hand.

• 15% tip on 68 split 4 ways
• split 240 between 5
• 12.5 percent service on 94

Working out a mark

A score out of an odd total is the single most searched calculation among students, and it is almost never asked as a percentage sum.

• 15/20 as a percentage
• what grade is 34 out of 50
• 34 out of 50 as a grade

Changing money

This is the one answer on the page that is not worked out from first principles, because an exchange rate is not a fact about arithmetic — it is a fact about today. The rate is fetched, the multiplication happens here, and the rate used is printed underneath along with the date it was published, so you can see what you are being told.

• 200 usd to pkr
• how much is 50 pounds in euros
• 1000 inr to gbp
• 200 dollars in pakistani rupees

A bare "rupees" is read as Indian, because that is what most people mean by it. The answer says so rather than hoping you agree — type pkr, lkr or npr and it uses those instead.

Everything else

• 5 km in miles
• -40 f to c
• days between 1 Jan 2026 and 25 Dec 2026
• bmi 80 kg 1.8 m
• 2 to the power of 10
• generate a strong password

That last one is the odd member of the list, and it earns its place for the same reason as the rest: your browser can do it without asking anyone. The password comes from the machine's own cryptographic random source, so it is never sent anywhere, never stored, and gone the moment you close the tab. Put a number in the question — password 24 — to set the length.

If a question lands outside all of that, the page says so and points at the tool that does handle it, rather than producing a number to fill the silence. That is a deliberate trade and the next section explains where the lines are.

What It Will Not Do

A tool that admits its limits is more useful than one that improvises past them, so three refusals are deliberate.

• Ambiguous dates. 03/04/2026 is the 3rd of April in Britain and the 4th of March in America. The page asks for 3 April 2026 or 2026-04-03 rather than picking one and being wrong for half its readers.
• Gallons and pints. A US gallon is about 3.79 litres and an imperial one about 4.55 — a difference of roughly a fifth. Length, weight and temperature are unambiguous, so those are supported and volume is not.
• A rate it cannot reach. Currency is the one answer that depends on something outside this page. When the rate is not available the question goes to the converter rather than to a figure from memory, and it is never quietly reinterpreted as some other sum that happens to fit the same numbers.
• Anything that is not a calculation. It will not tell you the weather, summarise an article or write anything. Ask it for those and it says so.

Verification and Review Date

The interpreter is covered by 119 tests that drive it exactly as the chat box does — every pattern in the table above, the conversions against their defined factors, and a set of questions it is expected to refuse, so that a future change cannot quietly turn a refusal into a guess. The arithmetic itself runs through that same expression parser, which carries 75 tests of its own.

Every example printed on this page is also a test in its own right. They are read out of the page itself and run against the live interpreter, so a phrase cannot sit here claiming to work after it has quietly stopped working — the check fails instead. Three of the examples above were rewritten because that test caught them doing exactly that. This page was last reviewed on 10 October 2026. Our about page describes how tools on this site are built and verified.

AI Calculator Questions