Free UK Calculators

Most money questions start the same way. You've got a number in front of you, a payslip, a house price, an invoice or a quote for a new driveway, and you want to know what it really means for you. AllCalculator is built for exactly that moment. It brings together 178 free UK calculators in one place, each one designed around UK rules, UK rates and the way people here actually search for answers.

Every calculator shows its working, so you can see how the answer was reached rather than trusting a single number. Tax and benefit calculators use the latest rates for the 2026/27 tax year, and each one comes with a plain-English guide that explains the rules, walks through an example and points you to the official source.

There's no sign-up and nothing to download. The figures you type stay in your browser.

Tax and salary calculators

If you want to know what you'll actually take home, start with our Salary Calculator. Enter your annual salary and it works out your take-home pay after Income Tax, National Insurance, pension contributions and student loan repayments, by year, month and week. It handles Scottish tax bands too.

From there you can dig into the detail. The Income Tax Calculator shows how much you pay in each band, including the 60% trap between £100,000 and £125,140. The National Insurance Calculator covers employee and employer Class 1 contributions. Thinking about a new job or a change in hours? The salary to hourly, pay rise and pro rata salary calculators show what the change means in your pocket.

For statutory pay, there are calculators for maternity pay, sick pay and redundancy pay, all using the current weekly rates and caps. You can also check your State Pension amount and age, work out overtime at time-and-a-half or double time, and make sure your hourly pay is above the National Minimum Wage.

• Salary Calculator: See your monthly pay after tax, NI, pension and student loan.
• Income Tax Calculator: Work out your income tax band by band, including Scotland.
• National Insurance Calculator: Employee and employer Class 1 NI on any salary.
• Salary to Hourly Calculator: Convert an annual salary to hourly, daily, weekly and monthly pay.
• Pay Rise Calculator: How much more you'll take home after a pay rise.
• Minimum Wage Checker: Check your hourly pay against the National Minimum Wage.
• Pension Contributions Calculator: Tax relief and employer contributions on your pension.
• Overtime Pay Calculator: Time-and-a-half, double time and your real overtime pay.
• Statutory Redundancy Pay Calculator: What you're owed by law if you're made redundant.
• Statutory Maternity Pay Calculator: SMP week by week for your leave.
• Statutory Sick Pay Calculator: How much SSP you'll get while off sick.
• UK State Pension Calculator: Your State Pension amount and the age you can claim it.
• Pro Rata Salary Calculator: Part-time and part-year pay from a full-time salary.
• NHS Annual Leave Calculator: Agenda for Change annual leave in hours, pro rata for part-time staff.

Mortgage and property calculators

Buying a home involves more sums than almost anything else. Our Stamp Duty Calculator covers SDLT in England and Northern Ireland, LBTT in Scotland and LTT in Wales, including first-time buyer relief and the surcharge on additional homes.

The mortgage affordability calculator gives you a realistic idea of how much you can borrow, while the Mortgage Payment Calculator shows your monthly repayment, the total interest and your balance year by year. Already have a mortgage? See how much you'd save by paying it off early.

Renting or letting? Check how much rent you can afford on your salary, or work out the gross and net yield on a buy-to-let. There are also calculators for council tax bands, Capital Gains Tax when you sell a second home, and whether a house extension is likely to count as permitted development.

• UK Stamp Duty Calculator: SDLT, LBTT and LTT for England, NI, Scotland and Wales.
• Mortgage Payment Calculator: Monthly repayments, total interest and your balance year by year.
• How Much Can I Borrow Mortgage Calculator: How much you could borrow from your income, deposit and commitments.
• Rent Affordability Calculator: How much rent you can afford on your salary.
• Council Tax Calculator: Your annual bill by band, including discounts.
• Buy-to-Let Yield Calculator: Gross and net rental yield on an investment property.
• Capital Gains Tax on Property Calculator: CGT when you sell a second home or buy-to-let, at 18% and 24%.
• Paying Mortgage Off Early Calculator: See how overpaying shortens your mortgage and saves interest.
• PD Calculator: Check whether a house extension is likely to be permitted development.
• Buy to Let Mortgage Calculator: Monthly payments and how much you can borrow against the rent.
• Land Registry Fee Calculator: The HM Land Registry fee for a purchase, remortgage, lease or first registration.
• Lease Extension Calculator: Estimate the premium to extend a flat lease by 90 years.

Business and self-employed calculators

Running a business means keeping on top of VAT, profit and tax. Our VAT Calculator adds or removes VAT at 20%, 5% or any custom rate in a couple of seconds. The Profit Margin Calculator shows margin and markup side by side, so you never confuse the two when pricing.

Sole traders can estimate their Income Tax and Class 4 National Insurance with the Self-Employed Tax Calculator. Limited company directors can compare Corporation Tax, dividend tax and the most tax-efficient mix of salary and dividends. In construction, the CIS Calculator works out the 20% or 30% deduction on a subcontractor's invoice after materials are taken off.

If you're buying equipment, vehicles or machinery, the finance calculators compare hire purchase and leasing costs, including VAT and balloon payments.

• VAT Calculator: Add or remove VAT at 20%, 5% or a custom rate.
• Self-Employed Tax Calculator: Income tax and Class 4 NI on your sole-trader profits.
• Dividend Tax Calculator: Tax on dividends alongside your salary.
• Corporation Tax Calculator: Small profits rate, main rate and marginal relief.
• Profit Margin Calculator: Margin, markup and profit from cost and selling price.
• Salary vs Dividends Calculator: The most tax-efficient way to pay yourself as a director.
• Machinery Finance Calculator: Hire purchase payments on plant and machinery, with VAT and balloon.
• Asset Finance Calculator: Compare hire purchase and leasing costs for business equipment.
• HGV Finance Calculator: Monthly payments on HGV hire purchase with deposit, balloon and VAT.
• CIS Calculator: Work out the CIS deduction and net payment on a subcontractor invoice.
• Financial Calculator: Solve for payment, future value, present value, term or interest rate.

Savings, loans and investment calculators

Small differences in interest rates add up over time. The Compound Interest Calculator shows how regular saving grows, and the savings interest calculator tells you how much of your interest is covered by your Personal Savings Allowance.

When you borrow, it pays to see the full cost. The Loan Repayment Calculator gives you the monthly payment and total interest on a personal loan, and the overpayment calculator shows how much you'd save by clearing it early. There are calculators for PCP car finance and boat loans too.

Looking further ahead, you can project a pension pot or an investment with fees and inflation, see what today's money will be worth in the future, estimate Inheritance Tax on an estate, and work out zakat on savings and gold.

• Compound Interest Calculator: Grow your savings with monthly deposits and compound interest.
• Loan Repayment Calculator: Monthly payments and total cost of a personal loan.
• Inheritance Tax Calculator: IHT on an estate, including the residence nil-rate band.
• Boat Finance Calculator: Monthly payments and total cost of a boat loan or marine mortgage.
• Savings Interest Calculator: Interest on your savings and how much is covered by your allowance.
• Pension Fund Calculator: Project your pension pot at retirement, including tax relief and charges.
• PCP Calculator: Monthly PCP payments, total cost and your options at the end.
• Inflation Calculator: What prices will cost in future and how inflation erodes savings.
• Investment Calculator: Project an investment with monthly contributions, fees and inflation.
• Zakat Calculator: Work out zakat on savings, gold, silver and investments.
• Loan Overpayment Calculator: How much interest you save by overpaying or settling a loan early.
• United States Inflation Calculator: What US dollars from any year since 1913 are worth today, using US CPI.

Everyday calculators

Some of the most useful calculators are the simplest. Our Percentage Calculator handles percentage increases and decreases, and the Calculator to Find Percentage works out what percentage one number is of another or finds the original amount before a discount.

There's an Age Calculator for your exact age in years, months and days, a days calculator that counts UK working days, and a holiday entitlement calculator for full-time and part-time workers. Planning a trip? Work out the fuel cost of a journey or convert US dollars to pounds.

You'll also find an energy bill calculator based on the current price cap, an ILR calculator for anyone planning to apply for Indefinite Leave to Remain, and a few lighter ones, such as a round robin fixture generator and a sun, moon and rising sign calculator.

• Percent Change Calculator: Percent of a number, percentage change and more.
• Calculator to Find Percentage: Find what percentage one number is of another, a % of a number, or the original amount.
• BMI Calculator: Body Mass Index in stones and pounds or kilograms.
• Age Calculator: Your exact age in years, months and days.
• Fuel Cost Calculator: Journey fuel cost using miles, MPG and pence per litre.
• Holiday Calculator: Your statutory annual leave in days or hours.
• Energy Bill Calculator: Estimate your gas and electricity costs.
• USD to British Pound Calculator: Convert US dollars to pounds at today's reference rate.
• Days Calculator: Count days and UK working days between dates, or add days.
• Round Robin Calculator: Matches, rounds and a full fixture list for any league.
• Sun Moon Rising Sign Calculator (Free): Free calculator for your sun, moon and rising signs.
• Chaldean Numerology Calculator: Your Chaldean name number and its traditional meaning.
• ILR Calculator UK: Find the earliest date you can apply for Indefinite Leave to Remain.
• Currency Calculator Euro: Convert euros to pounds or pounds to euros at today's reference rate.
• Algebra Math Calculator: Solve linear, quadratic and simultaneous equations, with the steps shown.
• Calculate Duration of Time: Hours and minutes between two times or dates, with breaks and pay.
• Scientific Calculator: Powers, roots, trig, logs and factorials. Type a calculation and get the answer.
• Unit Converter: Convert length, weight, volume, area, speed, temperature, energy and more.
• Schengen Calculator: Check your days in the Schengen area against the 90 in 180-day rule.

Home improvement and energy calculators

Before you ask for quotes, it helps to know roughly what a job should cost. Our home calculators give typical UK price ranges for a new driveway, a resin driveway or patio, house rendering, a flat roof, a retaining wall, glass and made-to-measure blinds.

For DIY and building work, there are calculators for plasterboard sheets, suspended ceiling tiles, roof slates and an area-weighted U-value. If you're improving your heating, size a radiator with the Radiator BTU Calculator, choose the right air conditioner, and see whether solar panels or a heat pump with solar would pay for itself.

• Driveway Cost Calculator: Estimate a new driveway in tarmac, block paving, gravel, concrete or resin.
• Resin Driveway Cost Calculator: Price a resin-bound driveway by area, base and edging.
• Resin Patio Cost Calculator: Estimate a resin-bound patio, including base and edging.
• Render Cost Calculator: Cost to render your house by wall area, render type and scaffolding.
• Flat Roof Cost Calculator: Replacement cost for felt, EPDM rubber and GRP fibreglass roofs.
• Retaining Wall Cost Calculator: Estimate sleeper, block, gabion or concrete retaining walls.
• Glass Price Calculator: Price and weight of cut-to-size glass by size, thickness and type.
• Blinds Cost Calculator: Made-to-measure blinds for every window, with fitting.
• Solar Panels Calculator: Generation, bill savings, export income and payback for solar PV.
• Air Conditioning Calculator: Find the right air conditioner size in BTU for your room.
• ROI Calculator for Air Source Heat Pump with Solar Panels: Savings, payback and return from a heat pump with solar panels.
• Area Weighted U Value Calculation: Average U-value and fabric heat loss across walls, roof, floor and windows.
• False Ceiling Calculator: Tiles, grid and wall angle for a suspended ceiling.
• Plaster Board Calculator: How many plasterboard sheets, screws and tape you need.
• Slate Roof Calculator: Slates, battens and nails for a natural or fibre cement slate roof.
• Radiator BTU Calculator: Find the heat output in BTU and watts a radiator needs for your room.
• Concrete Calculator: Concrete for a slab, footing or post holes in m³, bags and tonnes.
• Square Meter Calculator: Work out an area in square metres and square feet, with an optional cost.
• Aggregate Calculator: Tonnes and bulk bags of gravel, sub-base, sand or topsoil for an area.
• Construction Calculator: Add, subtract and multiply feet, inches and fractions, or convert to metric.

Health and family calculators

Our BMI Calculator works in stones and pounds or kilograms and uses the NHS adult categories. The Calorie Calculator estimates how many calories you need to maintain, lose or gain weight, and the water intake calculator suggests how much to drink each day.

For families, there's a pregnancy due date calculator with key scan dates, an ovulation calculator, a bra size calculator and a child maintenance calculator that uses the Child Maintenance Service formula. If you've challenged a PIP decision, the PIP Back Pay Calculator estimates the arrears you're owed.

Runners and lifters can predict a marathon time, set Norwegian singles interval paces or estimate a one-rep max. And if you're flying across time zones, the jet lag calculator helps you plan.

• Pregnancy Calculator: Your due date, how many weeks pregnant you are and key scan dates.
• Cervical Mucus Calculator: Your fertile window and ovulation date, with cervical mucus signs.
• Child Maintenance Calculator: Estimate weekly child maintenance using the CMS formula.
• Calorie Calculator: Daily calories to maintain, lose or gain weight.
• 1RM Calculator: Estimate your 1RM from any set and get training percentages.
• Bra Sizing Guide Calculator: Find your UK bra size from two simple measurements.
• Marathon Run Time Calculator: Predict your marathon time and pace from a recent race.
• Norwegian Singles Calculator: Sub-threshold interval paces for the Norwegian singles method.
• How Much Water to Drink to Lose Weight Calculator: How much water to drink a day, including when losing weight.
• Jet Lag Calculator: How long jet lag may last and how to adjust before you fly.
• PIP Back Pay Calculator: Estimate PIP arrears after a successful claim, reconsideration or appeal.
• How Many Weeks Pregnant Calculator: Find out exactly how many weeks and days pregnant you are today.
• Pregnancy Trimester Calculator: See which trimester you're in and the dates each trimester starts and ends.
• IVF Due Date Calculator: Your due date from a day 3, day 5 or day 6 embryo transfer, or egg collection.
• Pregnancy Weight Gain Calculator: Typical healthy weight gain for your BMI, week by week, including twins.
• Pregnancy Countdown Calculator: Count down the days and weeks to your due date, with milestones.
• How Much Weight Have I Lost Calculator: How much weight you've lost, as a percentage, per week and to your goal.
• Nursing Dosage Calculator: Tablets, liquid volumes, mg/kg doses, infusion and drip rates.
• Body Fat Calculator: Estimate your body fat percentage from a few tape measurements.
• BMR Calculator: Work out the calories your body burns at rest.
• Macro Calculator: Daily calories split into grams of carbs, protein and fat.
• Ideal Weight Calculator: Ideal body weight for your height using four classic formulas.
• Conception Calculator: Estimate when you conceived from your due date, last period or baby's birth date.
• Pace Calculator: Work out running pace, finish time or distance, in km or miles.
• Army Body Fat Calculator: US Army one-site tape test body fat estimate and age standard.
• Carbohydrate Calculator: How many grams of carbohydrate to eat a day.
• Lean Body Mass Calculator: Estimate your lean body mass from your height and weight.
• Healthy Weight Calculator: The healthy weight range for your height, in kg and stones.
• Calories Burned Calculator: Calories burned by walking, running, cycling, swimming and more.
• Target Heart Rate Calculator: Your maximum heart rate and heart rate training zones.
• Protein Calculator: How much protein to eat a day for your weight and activity.
• Fat Intake Calculator: How much fat and saturated fat to eat a day.
• Period Calculator: Predict your next periods and fertile windows.
• GFR Calculator: Estimate kidney function (eGFR) from a creatinine blood test.
• Body Type Calculator: Find your body shape from bust, waist and hip measurements.
• Body Surface Area Calculator: Body surface area from height and weight using five formulas.
• BAC Calculator: A rough estimate of your blood alcohol level and units drunk.

Student finance calculators

Student finance has its own rules. The Student Loan Calculator shows your repayments on Plans 1, 2, 4 and 5 and postgraduate loans, based on what you earn rather than what you borrowed. The Maintenance Loan Calculator estimates how much you can get towards living costs, depending on where you live and your household income.

• Student Loan Calculator: Repayments for Plans 1, 2, 4, 5 and postgraduate loans.
• Maintenance Loan Calculator: How much maintenance loan you can get.
• NEB GPA Calculator: Work out your NEB GPA from subject marks and credit hours.

Maths, science and engineering calculators

For students, engineers and anyone who works with numbers, our Scientific Calculator has a full keypad with trig, logs, powers, fractions and memory. The Graphing Calculator plots up to four functions, and the 3D Graphing Calculator draws surfaces you can rotate.

There are calculators for derivatives, integrals, matrices, statistics, complex numbers and binary, plus engineering tools for subnets, voltage drop, three-phase power, batteries and beam sections, and lab calculators for molarity, error propagation and sample sizes.

• Graphing Calculator: Plot up to four functions, zoom and read values off the graph.
• 3D Graphing Calculator: Draw a 3D surface z = f(x, y) and rotate it to see its shape.
• Derivative Calculator: Differentiate a function and evaluate the slope and tangent line at a point.
• Integral Calculator: Work out a definite integral and the area under a curve.
• Matrix Calculator: Determinant, inverse, transpose, rank and matrix arithmetic.
• Statistics Calculator: Mean, median, mode, standard deviation, quartiles and more from your data.
• Complex Number Calculator: Add, multiply, divide and raise complex numbers, with polar form.
• Binary Calculator: Binary arithmetic, bitwise operations and conversions to decimal and hex.
• Subnet Calculator: Network, broadcast, host range and mask for any IPv4 address and prefix.
• Voltage Drop Calculator: Voltage drop for a cable run, checked against BS 7671 limits.
• Three-Phase Power Calculator: Convert between three-phase current, kW, kVA and kVAr.
• Battery Calculator: How long a battery will run a load, in hours and minutes.
• Moment of Inertia Calculator: Second moment of area and section modulus for beams and tubes.
• Molarity Calculator: Mass, molarity and volume of a solution, plus C₁V₁ = C₂V₂ dilutions.
• Error Propagation Calculator: Combine measurement uncertainties through any formula.
• Sample Size Calculator: How many responses you need for a survey's confidence and margin of error.
• Basic Calculator: A simple online calculator for adding, subtracting, multiplying and dividing.
• Fraction Calculator: Add, subtract, multiply, divide and simplify fractions and mixed numbers.
• Triangle Calculator: Solve any triangle from three sides, two sides and an angle, or two angles and a side.
• Volume Calculator: Volume of a cube, cuboid, cylinder, cone, sphere and more, with litres.
• Surface Area Calculator: Total surface area of 3D shapes, from cubes to cones.
• Area Calculator: Area and perimeter of rectangles, triangles, circles and other 2D shapes.
• Circle Calculator: Radius, diameter, circumference and area from any one of them.
• Pythagorean Theorem Calculator: Find the missing side of a right-angled triangle with a² + b² = c².
• Right Triangle Calculator: Solve a right-angled triangle from two sides or a side and an angle.
• Slope Calculator: Slope, equation of the line, angle and distance between two points.
• Distance Calculator: Distance between two points in 2D, 3D or on the Earth's surface.
• Random Number Generator: Pick random whole numbers or decimals in any range.
• Number Sequence Calculator: Find the nth term and sum of a sequence, or the pattern in your numbers.
• Percent Error Calculator: How far a measured value is from the true value, as a percentage.
• Exponent Calculator: Raise a number to any power, or find the exponent.
• Log Calculator: Logarithms in base 10, e, 2 or any base.
• Root Calculator: Square roots, cube roots and nth roots, with simplified surds.
• Half-Life Calculator: Amount remaining, half-life or time from exponential decay.
• Quadratic Formula Calculator: Solve ax² + bx + c = 0 with the quadratic formula.
• Probability Calculator: Probability of A and B, A or B, neither, and repeated events.
• Permutation and Combination Calculator: nCr and nPr, with and without repetition.
• Z-score Calculator: Z-score, percentile and probabilities for a normal distribution.
• Confidence Interval Calculator: Confidence interval for a mean or a proportion.
• P-value Calculator: P-value from a z, t, chi-square or F test statistic.
• Ratio Calculator: Simplify ratios, find missing values and share amounts in a ratio.
• Least Common Multiple Calculator: The lowest common multiple of two or more numbers.
• Greatest Common Factor Calculator: The greatest common factor (HCF) of two or more numbers.
• Common Factor Calculator: All the factors two or more numbers share.
• Factor Calculator: All the factors and factor pairs of a number.
• Prime Factorization Calculator: Break a number into its prime factors, with a division ladder.
• Rounding Calculator: Round to decimal places, significant figures or the nearest 10, 100…
• Scientific Notation Calculator: Convert to and from scientific notation (standard form), and do sums.
• Big Number Calculator: Exact arithmetic on whole numbers of any size.
• Long Division Calculator: Long division step by step, with the remainder and decimal.

Why use AllCalculator?

• Built for the UK. Every calculator uses UK rules, from Scottish tax bands to Welsh Land Transaction Tax and NHS health categories.
• Up to date. Tax, National Insurance, benefit and property tax rates are kept in one place and updated each April and after each Budget.
• Working shown. You'll see a breakdown, not just a total, so you can check every step.
• Private. Calculations run in your browser, and we don't store the numbers you enter.
• Explained properly. Each calculator has its own guide, written in plain English and linked to official sources such as GOV.UK and HMRC.