calcular.eu

Online calculator

Plus a calculator for everything else: percentages, VAT, money, health, dates, currencies and units. Free, no sign-up.

All calculators

Maths

• Scientific calculator — Sines, logarithms, powers, roots and factorials, with history.
• Percentages — X% of an amount, what percentage, increases, decreases and change.
• Rule of three — Direct and inverse proportion, with the working.
• Fractions — Add, subtract, multiply, divide and simplify fractions.
• Powers, roots and logarithms — Any exponent, nth root and logarithm in any base.
• Equations — Linear, quadratic and systems of two equations.
• Mean, median and mode — Mean, median, mode, range, variance and standard deviation of a list.
• GCD and LCM — Greatest common divisor, least common multiple and prime factors.
• Area and perimeter — Square, rectangle, triangle, circle, trapezoid, rhombus and polygons.
• Roman numerals — Convert numbers to Roman numerals and back.
• Random numbers — Random numbers between two values, with or without repeats.

Finance

• Loans and mortgages — Monthly payment, interest and amortization schedule. Part-fixed mortgages too.
• Compound interest — How your money grows with regular contributions and reinvested interest.
• Currency converter — Euros, dollars, pounds and 30+ currencies at the official ECB rate.
• Gold and precious metals — Value of your gold, silver, platinum or palladium jewellery, coins or bars by weight and purity.
• Loan comparison — Compare two loan offers and see which one is cheaper.
• Mortgage overpayment — How much you save by paying off early: lower payment or shorter term.
• Fixed-term deposits — Interest and APY by term or by exact days, with tax withholding.
• Investment return — Year-by-year projection after inflation and tax.
• Inflation and purchasing power — How much your money loses to inflation over the years.
• Financial independence (FIRE) — When you could live off your investments with the 4% rule.
• Emergency fund — How many months until you reach your savings cushion.
• Debt payoff planner — Avalanche or snowball method to get out of debt sooner.
• Loan or lease — Compare the real cost of a loan against a lease.

Housing

• How much can I borrow? — Maximum mortgage and home price from your income and savings.
• Rent increase (CPI) — New rent after the annual review: a percentage, or Spain’s IRAV and CPI updated automatically.
• Rent or buy — Wealth from buying versus renting and investing the difference.
• Rental yield (Spain) — Gross and net yield, cash flow and payback of a rental property, with Spanish tax.

Work and pay

• Spain net salary (IRPF 2026) — Gross to net and net to gross in Spain, with overtime and self-employed.
• Hourly wage — Turn an hourly rate into a monthly or annual salary, and back.
• Hours worked — Weekly hours with several schedules, split shifts and earnings.
• Severance pay (Spain) — Final settlement and severance pay under Spanish employment law.
• Holiday entitlement (Spain) — Days you’re entitled to in Spain, days left and what they’re worth.

Business and marketing

• VAT — Add or remove VAT with UK and European rates.
• Margin and markup — Profit margin, markup and selling price from cost.
• Break-even point — How many units you need to sell to cover your costs.
• Profit margin and VAT — Margins, VAT and break-even for a product, with a product library.
• ROAS and ad ROI — Return on ad spend and the minimum ROAS to make money.
• CPM, CPC and CTR — Cost per thousand, per click, per acquisition and click-through rate.
• CAC and LTV — Cost to acquire a customer, what they’re worth and payback time.
• Conversion rate — Share of visits that buy, and what each visit is worth.

Health and fitness

• BMI — Body mass index with its category and your healthy weight.
• Daily calories — Basal metabolic rate and calories to maintain, lose or gain weight.
• Ideal weight — Ideal weight for your height with four formulas and the healthy range.
• Body fat — Body fat percentage with a tape measure (US Navy method).
• Daily water — How much water to drink a day based on weight, exercise and heat.
• Pregnancy due date — Estimated due date, weeks pregnant and trimester.
• Ovulation and fertile days — Your fertile window and ovulation date for the next cycles.
• Running pace — Pace per kilometre or mile, finish time or distance.
• Heart rate zones — Maximum heart rate and your five training zones.

Dates and time

• Days between dates — Days, weeks, months and business days between two dates.
• Exact age — Your age in years, months and days, and days until your birthday.
• Anniversary — How long you’ve been together, days until your anniversary and its traditional name.
• Add days to a date — Add or subtract days, weeks, months or years from a date.
• Business days — Working days between two dates, without weekends or holidays.
• Add hours and minutes — Add and subtract times in hours, minutes and seconds.

Unit converters

• Length — Metres, kilometres, inches, feet, miles and more.
• Weight — Kilograms, grams, pounds, ounces, tonnes and stone.
• Temperature — Celsius, Fahrenheit and Kelvin.
• Volume — Litres, millilitres, cubic metres, gallons, cups and spoons.
• Area — Square metres, hectares, acres, square feet and more.
• Speed — km/h, m/s, miles per hour and knots.
• Time — Seconds, minutes, hours, days, weeks, months and years.
• Digital data — Bytes, KB, MB, GB, TB and their binary versions (KiB, MiB…).
• Pressure — Bar, pascals, atmospheres, PSI and mmHg.
• Energy — Joules, calories, kilocalories, kWh and BTU.
• Fuel economy — L/100 km, km/L and miles per gallon (US and UK).
• Binary, decimal and hex — Convert between binary, octal, decimal and hexadecimal.

Everyday

• Discounts and sales — Final price with one or two discounts, and the real percentage off.
• Tip and bill splitter — Tip, total and how much each person pays.
• Car trip cost — Fuel or electricity cost of a journey and each passenger’s share.
• Weighted average grade — Average of your grades with their weight or credits.
• Unit price and deals — Price per kilo, litre or unit and the real saving of every deal.