VAT Flat Rate vs Standard: Which Should My Business Pick?
Flat rate vs standard VAT — the maths and the trade-offs.
Mathematics
Every Maths calculadora on Calculadora.co.uk — free, fast and built for the UK.
Clear, reliable maths calculadoras for GCSE, A-Level, uni and everyday life. Percentages, areas, trigonometry, statistics and more — with the formulas shown, not hidden.
58 calculators in this category · updated weekly
Add, subtract, multiply and invert 2×2 matrices, plus determinant and transpose — ideal for A-Level further maths and first-year linear algebra.
Work with 3×3 matrices — determinant (cofactor expansion), inverse, transpose and multiplication — with every step shown.
Compute binomial probabilities P(X=k), P(X≤k) and P(X≥k) for n trials with success probability p — with mean np and variance np(1−p).
Work out the area of a circle from its radius, diameter or circumference using πr².
Work out the circumference of a circle using 2πr.
Count the number of ways to choose r items from n without regard to order, using the binomial coefficient n! / (r!(n−r)!).
Project the future value of savings or investments with compounding, regular contributions and inflation-adjusted returns.
Work out 90%, 95% or 99% confidence intervals for a mean or proportion, with sample-size guidance and margin of error shown.
Compute Pearson’s correlation coefficient r between two data sets, with strength, direction and coefficient of determination R² explained.
Compute cosine of any angle in degrees or radians, and use the inverse (arccos) to find an angle from a ratio. Ideal for trigonometry homework and surveying.
Calculate the cross product of two 3D vectors, giving a perpendicular vector with magnitude equal to the parallelogram area they span.
Work out the total or lateral surface area of a cylinder from its radius and height. Shows the formulas (2πrh + 2πr² and 2πrh) with a worked example in metric units.
Compute the determinant of a 2×2, 3×3 or 4×4 matrix using Leibniz expansion or cofactor expansion, with a worked example and sign chart.
Work out the probability of rolling a given sum, a specific pattern, or "at least N" on any number of D4–D100 dice.
Compute the Euclidean distance between two 2D or 3D points with d = √((x₂−x₁)² + (y₂−y₁)² + (z₂−z₁)²).
Compute the dot product of two vectors and the angle between them — scalar projection and work done (force·displacement) in one place.
Raise any base to any exponent — including fractional and negative exponents — and see the result in both decimal and scientific notation.
Calculate n! for any non-negative integer.
Add, subtract, multiply and divide fractions, convert decimals to fractions, and simplify to lowest terms — with each step shown clearly.
Find the greatest common divisor (also called GCF or HCF) of two or more integers using the Euclidean algorithm, with step-by-step working.
Calculate the hypotenuse of a right triangle from its two legs.
Work out the least common multiple of two or more integers using LCM × GCD = product, with a prime-factorisation method for larger numbers.
Solve any linear equation ax + b = c for x, with step-by-step rearrangement and tips for equations with fractions or brackets.
Evaluate log base 10, natural log (ln) and log of any custom base. Includes change-of-base formula and worked examples for compound interest and pH.
Divide any two integers with the full long-division workings shown — divisor, dividend, quotient, remainder and carry, row by row.
Add up your values and divide by how many there are — we show each step.
Find the middle value of any data set.
Find the midpoint of a line segment between two 2D or 3D points using the coordinate-average formula M = ((x₁+x₂)/2, (y₁+y₂)/2).
Find the most frequent value(s) in a data set.
Find the remainder when one integer is divided by another with a mod b = r, plus negative-dividend and modular-arithmetic cases.
Work out a percentage of a value, the percentage between two values, and percentage increases or decreases — with the formula shown.
Count ordered arrangements of r items out of n using n! / (n−r)! — with and without repetition cases explained.
Break any positive integer into its prime factors using trial division, with a factor tree and exponent form output.
Work out single-event, independent and conditional probabilities, plus union and intersection using the addition and multiplication rules.
Solve proportions of the form a/b = c/d for any missing term, with direct and inverse proportion worked through step by step.
Find the hypotenuse or a missing side of a right-angled triangle using a² + b² = c².
Solve ax² + bx + c = 0 using the quadratic formula — with discriminant and step-by-step working.
Solve any quadratic ax² + bx + c = 0 with the quadratic formula (also known as Bhaskara in Brazilian classrooms). Shows the discriminant, both roots and the nature of the solutions.
Simplify ratios, scale them up or down, and split a quantity in a given ratio — ideal for recipes, mixing fluids or sharing costs fairly.
Multiply length by width to find the area of any rectangle.
Work out the perimeter of a rectangle with the formula P = 2 × (length + width). Handy for skirting-board, fencing and picture-frame jobs.
Convert any number between 1 and 3,999,999 to and from Roman numerals — with the classic subtractive rules and vinculum overbar explained.
Round any number to the nearest whole, decimal place, significant figure or multiple, with tie-breaking modes (half-up, banker’s rounding) explained.
Solve a proportion by cross-multiplication — the classic rule-of-three used for recipe scaling, unit pricing and percent conversions.
Convert numbers to and from scientific notation and engineering notation, plus add, subtract, multiply and divide values expressed as a × 10ⁿ.
Calculate simple interest on a loan or savings account using principal, rate and time.
Calculate sine of any angle in degrees or radians, plus inverse sine (arcsin) for finding an angle from a side ratio. Includes unit-circle reference values.
Find the slope of a straight line from two points using m = (y₂ − y₁) / (x₂ − x₁), plus the equation of the line and its y-intercept.
Calculate the area of a square from its side length.
Multiply any side by four to get the perimeter of a square. Shows the formula P = 4s with a UK-sized worked example.
Measure the spread of a data set with sample or population standard deviation.
Solve 2×2 and 3×3 linear systems by substitution, elimination or Cramer’s rule, with the full step-by-step.
Work out tangent of any angle, and the inverse tangent (arctan or atan) for finding an angle from a ratio — including the opposite-over-adjacent shortcut.
Find the area of a triangle using base × height ÷ 2 or Heron's formula.
Add the three sides of any triangle to get the perimeter. Supports scalene, isosceles and equilateral, with shortcut formulas and a worked example.
Find the magnitude of a 2D or 3D vector from its components using the Pythagorean identity, plus the unit vector and direction cosines.
Compute a weighted mean where each value carries a different weight — ideal for coursework grades, portfolio returns and sample averages.
Convert a raw score into a z-score using z = (x − μ) / σ, plus the two-tailed p-value from the standard normal distribution.
Add, subtract, multiply and invert 2×2 matrices, plus determinant and transpose — ideal for A-Level further maths and first-year linear algebra.
Work with 3×3 matrices — determinant (cofactor expansion), inverse, transpose and multiplication — with every step shown.
Compute the determinant of a 2×2, 3×3 or 4×4 matrix using Leibniz expansion or cofactor expansion, with a worked example and sign chart.
Raise any base to any exponent — including fractional and negative exponents — and see the result in both decimal and scientific notation.
Solve any linear equation ax + b = c for x, with step-by-step rearrangement and tips for equations with fractions or brackets.
Evaluate log base 10, natural log (ln) and log of any custom base. Includes change-of-base formula and worked examples for compound interest and pH.
Solve any quadratic ax² + bx + c = 0 with the quadratic formula (also known as Bhaskara in Brazilian classrooms). Shows the discriminant, both roots and the nature of the solutions.
Solve 2×2 and 3×3 linear systems by substitution, elimination or Cramer’s rule, with the full step-by-step.
Compute binomial probabilities P(X=k), P(X≤k) and P(X≥k) for n trials with success probability p — with mean np and variance np(1−p).
Work out 90%, 95% or 99% confidence intervals for a mean or proportion, with sample-size guidance and margin of error shown.
Compute Pearson’s correlation coefficient r between two data sets, with strength, direction and coefficient of determination R² explained.
Work out the probability of rolling a given sum, a specific pattern, or "at least N" on any number of D4–D100 dice.
Work out single-event, independent and conditional probabilities, plus union and intersection using the addition and multiplication rules.
Compute a weighted mean where each value carries a different weight — ideal for coursework grades, portfolio returns and sample averages.
Convert a raw score into a z-score using z = (x − μ) / σ, plus the two-tailed p-value from the standard normal distribution.
Work out the total or lateral surface area of a cylinder from its radius and height. Shows the formulas (2πrh + 2πr² and 2πrh) with a worked example in metric units.
Compute the Euclidean distance between two 2D or 3D points with d = √((x₂−x₁)² + (y₂−y₁)² + (z₂−z₁)²).
Find the midpoint of a line segment between two 2D or 3D points using the coordinate-average formula M = ((x₁+x₂)/2, (y₁+y₂)/2).
Work out the perimeter of a rectangle with the formula P = 2 × (length + width). Handy for skirting-board, fencing and picture-frame jobs.
Find the slope of a straight line from two points using m = (y₂ − y₁) / (x₂ − x₁), plus the equation of the line and its y-intercept.
Multiply any side by four to get the perimeter of a square. Shows the formula P = 4s with a UK-sized worked example.
Add the three sides of any triangle to get the perimeter. Supports scalene, isosceles and equilateral, with shortcut formulas and a worked example.
Divide any two integers with the full long-division workings shown — divisor, dividend, quotient, remainder and carry, row by row.
Find the remainder when one integer is divided by another with a mod b = r, plus negative-dividend and modular-arithmetic cases.
Break any positive integer into its prime factors using trial division, with a factor tree and exponent form output.
Round any number to the nearest whole, decimal place, significant figure or multiple, with tie-breaking modes (half-up, banker’s rounding) explained.
Compute cosine of any angle in degrees or radians, and use the inverse (arccos) to find an angle from a ratio. Ideal for trigonometry homework and surveying.
Calculate sine of any angle in degrees or radians, plus inverse sine (arcsin) for finding an angle from a side ratio. Includes unit-circle reference values.
Work out tangent of any angle, and the inverse tangent (arctan or atan) for finding an angle from a ratio — including the opposite-over-adjacent shortcut.
Calculate the cross product of two 3D vectors, giving a perpendicular vector with magnitude equal to the parallelogram area they span.
Compute the dot product of two vectors and the angle between them — scalar projection and work done (force·displacement) in one place.
Find the magnitude of a 2D or 3D vector from its components using the Pythagorean identity, plus the unit vector and direction cosines.
A quick glossary covering the controlled vocabulary we keep consistent across every calculator in this cluster.
Flat rate vs standard VAT — the maths and the trade-offs.
Compound interest — the maths and the UK wrappers.
A Brazilian-classroom favourite explained for English readers too.