Middle School Calculators
207+ free calculators with step-by-step solutions. Search, filter, and solve.
Calculator tools
Full calculators for when you need more than one formula.
Percentage Calculation
Percentage = (part/whole) × 100
Calculate what percentage one number is of another
Percentage Increase/Decrease
Percentage Change = ((New Value - Old Value) ÷ Old Value) × 100
Calculate percentage increase or decrease between two values
Add Fractions
a/b + c/d = (ad + bc) / bd
Add two fractions and simplify the answer
Multiply Fractions
a/b × c/d = ac / bd
Multiply two fractions and simplify the answer
Divide Fractions
a/b ÷ c/d = ad / bc
Divide one fraction by another using the reciprocal
Subtract Fractions
a/b - c/d = (ad - bc) / bd
Subtract one fraction from another and simplify
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HCF / GCD Calculator
HCF(a, b) = largest number dividing both a and b
Find the Highest Common Factor (Greatest Common Divisor) of two numbers
LCM Calculator
LCM(a, b) = (a × b) ÷ HCF(a, b)
Find the Lowest Common Multiple of two numbers
Marks Percentage Calculator
Percentage = (Marks Obtained ÷ Total Marks) × 100
Calculate exam percentage and grade from marks scored
Median Calculator
Middle value of ordered data set
Find the median (middle value) of a set of numbers
Mode Calculator
Most frequently occurring value
Find the mode (most common value) in a set of numbers
Area of Circle
A = π × r²
Calculate the area of a circle using its radius
Area of Triangle
A = ½bh
Calculate the area of a triangle
Pythagorean Theorem
c² = a² + b²
Find the hypotenuse of a right triangle
Circumference of Circle
C = 2πr
Calculate the circumference of a circle
Slope Formula
m = (y₂ - y₁)/(x₂ - x₁)
Calculate the slope between two points
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Exponent Calculator
result = baseⁿ
Raise a number to a power
Square Root
√n
Find the square root of a number
Cube Root
∛n
Find the cube root of a number
Simple Interest
I = P × r × t
Calculate simple interest on a principal amount
Sales Tax / GST Calculator
Total = Amount + (Amount × Rate / 100)
Calculate tax amount and total price including sales tax, GST or VAT
Speed Calculator
Speed = Distance ÷ Time
Calculate speed from distance and time
Density Formula
ρ = m / V
Calculate density from mass and volume
Ratio Simplifier
a : b = (a ÷ HCF) : (b ÷ HCF)
Reduce a ratio to its simplest whole-number form
Proportion Solver
a/b = c/x → x = (b × c) / a
Solve for the missing value in a proportion using cross multiplication
Prime Factorization
n = p₁ × p₂ × p₃ × ...
Break a number down into its prime factors
Volume of Rectangular Prism
V = l × w × h
Calculate the volume of a rectangular prism
Area of Parallelogram
A = base × height
Calculate the area of a parallelogram
Area of Trapezoid
A = (a + b) × h ÷ 2
Calculate the area of a trapezoid
Linear Equation Solver
ax + b = c → x = (c - b) ÷ a
Solve linear equations in the form ax + b = c
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Profit/Loss Calculator
Profit/Loss = Selling Price - Cost Price
Calculate profit or loss percentage
Scientific Notation
n = m × 10ᵏ where 1 ≤ |m| < 10
Write a number in scientific notation
Area of Rhombus
A = (d₁ × d₂) / 2
Calculate the area of a rhombus from its diagonals
Surface Area of Cube
A = 6a²
Calculate the total surface area of a cube
Polygon Interior Angles
Sum = (n - 2) × 180°
Find the sum of interior angles of a polygon and each angle if regular
Diagonal of Rectangle
d = √(l² + w²)
Calculate the diagonal of a rectangle
Range Calculator
Range = maximum - minimum
Find the range of a data set
Weighted Average
Weighted Average = (v₁w₁ + v₂w₂) / (w₁ + w₂)
Calculate the weighted average of two values
Salary to Hourly Rate
Hourly = Annual Salary / (Hours per Week × 52)
Convert an annual salary into an hourly pay rate
Number Base Converter
Convert a value between number bases 2-10 via decimal
Convert a whole number (e.g. binary, octal, decimal) between number bases 2 through 10
Prime Number Checker
n is prime if it has no divisors other than 1 and itself
Check whether a whole number is a prime number
Speed Unit Converter
Various conversion factors
Convert between different units of speed (m/s, km/h, mph, knots)
Braces Cost Calculator
Monthly Payment = (Total Cost − Down Payment) ÷ Months
Estimate the monthly payment for orthodontic braces on a payment plan
Tutoring Cost Calculator
Total Cost = Rate × Hours per Week × Weeks
Estimate the total cost of tutoring sessions over a school term
GST / VAT Calculator
Add: Total = Amount × (1 + rate) · Remove: Base = Amount ÷ (1 + rate)
Add GST/VAT to a price or remove it from a tax-inclusive price. Mode: 1 = add tax, 2 = remove tax
Fuel Cost Calculator
Cost = (Distance ÷ Efficiency) × Price per litre
Trip fuel cost from distance, your vehicle's fuel efficiency and the fuel price
Ideal Weight Calculator
Devine: 50 kg (men) / 45.5 kg (women) + 2.3 kg per inch over 5 ft
Ideal body weight for your height using the Devine formula, compared with the Robinson, Miller and Hamwi formulas. Sex: 1 = male, 2 = female
Percentage Error Calculator
% error = |measured − actual| ÷ |actual| × 100
How far a measured or estimated value is from the true value, as a percentage
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