Free Calculators Tools

Which one do you actually need?

Four of these are about money you are about to spend: the discount calculator for what a sale price really is, the VAT calculator for adding or stripping tax, the tip calculator for splitting a bill, and the percentage calculator for everything else of that shape.

Two are about money over time, and they are the ones worth slowing down for. The loan calculator shows the monthly payment and, more usefully, the total interest, which is the number lenders quote last. The compound interest calculator shows the same force working in your favour, and the gap between a monthly and an annual compounding period over twenty years surprises most people.

The unit converter and temperature converter handle measurements, and the BMI calculator is here with a caveat large enough that it has its own article.

What this category will not do for you

None of this is financial advice, and two of these calculations are regularly used as if they answered a question they do not. A loan payment you can afford is not the same as a loan worth taking; the total interest is the figure that decides that. BMI is a ratio of weight to height that was devised to describe populations, and it says nothing about an individual's muscle, frame or health.

Tax rules also vary by country and by what is being sold. The VAT calculator does the arithmetic correctly for the rate you give it, and choosing the right rate is still on you.

Frequently asked questions

How do I remove VAT from a price that already includes it?

Divide by one plus the rate, rather than subtracting the percentage. At 21 percent, a gross price of 121 becomes 121 divided by 1.21, which is 100. Subtracting 21 percent from 121 gives 95.59, which is wrong, and the gap grows with the rate.

Why is a 20 percent discount then a 10 percent discount not 30 percent off?

Because the second discount applies to the already reduced price rather than the original. Twenty percent off 100 gives 80, and ten percent off 80 gives 72, which is 28 percent off in total. Stacked discounts always come to less than the sum of their parts.

Does the loan calculator include fees and insurance?

No. It calculates payments from the principal, the rate and the term, which is the arithmetic of the loan itself. Origination fees, insurance and administrative charges vary by lender and are added on top. The annual percentage rate on a lender’s offer is usually the figure that includes them.