Finance Calculators

Everyday money maths

These finance calculators handle the questions that come up in ordinary life and planning — not stock-picking, just the arithmetic of borrowing, saving, and comparing. The loan calculatorworks out a monthly payment (or how long a loan will take to clear) along with the total interest you'll pay, so you can see the real cost of borrowing before you sign. Thecompound interest calculatordoes the opposite job for savings, showing how a lump sum grows over time and what the effective annual rate really is.

The percentage calculator covers the small daily calculations — discounts, tips, test scores, and tracking how much a number has gone up or down — while theVAT calculator adds or removes sales tax at any rate. The savings goal calculatorworks out what to put aside each month to hit a target, or how long a set amount will take. Each tool shows the formula it uses and a worked example, so the result is something you can follow and check rather than just trust. Figures are estimates for planning; they don't account for fees, tax, or changing rates.

Simple, compound, and why the difference grows

The most important distinction in this category is whether interest earns interest. Simple interest is charged on the original principal only, which is how many short-term notes and bonds work. Compound interest is charged on the balance including previously accrued interest, which is how savings accounts, mortgages and credit cards work.

Over one year at annual compounding the two agree exactly. Beyond that they diverge, slowly at first and then not slowly at all — which is the entire argument for saving early, and the entire danger of carrying a credit card balance.

Rates are quoted in more than one way

A "5% rate" can mean several different things. A nominal annual rate compounded monthly does not deliver 5% over the year — it delivers slightly more, because each month's interest starts earning. Lenders and savings providers are generally required to quote a comparable effective figure precisely because the nominal number is easy to misread. When you enter a rate here, enter the one your provider actually applies, and check whether it is nominal or effective.

What these deliberately do not model

Tax, fees and inflation are absent unless a page says otherwise. A savings projection that ignores tax on the interest overstates what you keep. A loan comparison that ignores arrangement fees can rank two offers the wrong way round. And a long-run figure in today's money says nothing about what it will buy — theinflation calculator exists to make that adjustment separately.

These are planning tools for understanding the shape of a decision, not a substitute for the actual terms of an actual product. For anything with real money behind it, read the agreement, and where the sums are significant take advice from someone qualified to give it.