108 free calculators, one site.
Finance, health, math, physics, and business — fast, mobile-friendly, no sign-up.
Finance
View all →Simple Interest Calculator
Calculate simple interest earned on a principal amount over time.
Compound Interest Calculator
Calculate compound interest on an investment with configurable compounding frequency.
Loan EMI Calculator
Calculate the Equated Monthly Installment (EMI) for any loan.
Mortgage Calculator
Calculate monthly mortgage payment, total interest, and optional total housing cost including tax and insurance.
ROI Calculator
Calculate Return on Investment as a percentage of cost.
CAGR Calculator
Calculate the compound annual growth rate of an investment over multiple years.
Discount Calculator
Calculate sale price and savings after applying a percentage discount.
Future Value Calculator
Project the future value of a lump-sum investment.
Investment Growth Calculator
Project growth of an initial investment with optional monthly contributions.
Dividend Yield Calculator
Calculate dividend yield and annual income from a stock holding.
SIP Calculator
Calculate future value of a Systematic Investment Plan with monthly contributions.
Amortization Calculator
Generate a loan amortization schedule showing principal, interest, and balance per month.
Interest Rate Calculator
Solve for the annual interest rate given starting amount, ending amount, and time.
Inflation Impact Calculator
Calculate the real (inflation-adjusted) value of money in the future, and the loss of purchasing power.
Salary Increase Impact Calculator
Compare nominal vs real salary growth after inflation. See whether your raise is actually a raise.
Interest Rate Change Impact Calculator
Calculate how a change in interest rate affects your monthly mortgage/loan payment and total cost over the life of the loan.
Health
View all →BMI Calculator
Calculate Body Mass Index from weight and height. Get your category (underweight/normal/overweight/obese).
BMR Calculator
Calculate Basal Metabolic Rate using the Mifflin-St Jeor equation.
TDEE Calculator
Calculate Total Daily Energy Expenditure based on BMR and activity level.
Body Fat Calculator (US Navy)
Estimate body fat percentage using the US Navy circumference method.
Calorie Calculator
Calculate daily calorie target for weight loss, maintenance, or gain.
Ideal Weight Calculator
Calculate ideal body weight using four established formulas (Devine, Robinson, Miller, Hamwi).
Water Intake Calculator
Estimate daily water intake based on body weight and exercise duration.
Heart Rate Zone Calculator
Calculate the five heart rate training zones based on your age-predicted maximum.
Math
View all →Percentage Calculator
Solve the three core percentage problems: what is X% of Y, X is what % of Y, and percentage increase/decrease.
Fraction Calculator
Add, subtract, multiply, or divide two fractions and get a simplified result.
Ratio Calculator
Simplify a ratio and solve missing terms in proportional ratios.
Average Calculator
Compute the arithmetic mean of a list of numbers.
Median Calculator
Find the middle value of a list of numbers.
Mode Calculator
Find the most frequently occurring value(s) in a dataset.
Standard Deviation Calculator
Calculate population and sample standard deviation and variance.
Variance Calculator
Calculate the variance of a dataset.
Probability Calculator
Calculate single-event probability and the complement.
Permutation Calculator
Calculate the number of ordered arrangements (permutations) of r items from n.
Combination Calculator
Calculate the number of unordered selections (combinations) of r items from n.
LCM Calculator
Find the least common multiple of two or more integers.
GCD Calculator
Find the greatest common divisor of two or more integers.
Quadratic Equation Solver
Solve ax² + bx + c = 0 for both real and complex roots.
Linear Equation Solver
Solve ax + b = 0 for x.
Pythagoras' Theorem Calculator
Solve a² + b² = c² for any side of a right triangle.
Distance Formula Calculator (2D)
Calculate the straight-line distance between two points in a 2D plane.
Distance Formula Calculator (3D)
Calculate the straight-line distance between two points in 3D space.
Midpoint Calculator
Find the midpoint of the line segment between two 2D points.
Slope Calculator
Calculate the slope, y-intercept, and equation of the line through two points.
Trigonometry Calculator
Compute sin/cos/tan/sec/csc/cot of an angle, or arcsin/arccos/arctan of a value.
Logarithm Calculator
Compute logarithms in any base — natural log (ln), common log (log₁₀), or a custom base.
Exponential Calculator
Compute b^x (b raised to the power x) for any base and exponent, including e^x.
Geometry
View all →Square Area Calculator
Calculate area, perimeter, and diagonal of a square from its side length.
Rectangle Area Calculator
Calculate area, perimeter, and diagonal of a rectangle.
Triangle Area Calculator
Calculate triangle area from base × height, or from three sides using Heron's formula.
Circle Area Calculator
Calculate area, circumference, diameter, and radius of a circle. Solve from any one value.
Parallelogram Area Calculator
Calculate area and perimeter of a parallelogram.
Trapezoid Area Calculator
Calculate area and perimeter of a trapezoid (trapezium).
Rhombus Area Calculator
Calculate area of a rhombus from its two diagonals, plus perimeter from the side length.
Ellipse Area Calculator
Calculate area and approximate circumference of an ellipse from its semi-major and semi-minor axes.
Regular Polygon Calculator
Calculate area, perimeter, and interior angle of a regular polygon.
Cube Volume Calculator
Calculate volume, surface area, and space diagonal of a cube.
Cuboid Volume Calculator
Calculate volume, surface area, and space diagonal of a cuboid (rectangular box).
Sphere Volume Calculator
Calculate volume and surface area of a sphere from radius, diameter, volume, or surface area.
Cylinder Volume Calculator
Calculate volume, total surface area, and lateral (curved) surface area of a cylinder.
Cone Volume Calculator
Calculate volume, surface area, and slant height of a right circular cone.
Square Pyramid Volume Calculator
Calculate volume, surface area, and slant height of a square-based pyramid.
Torus Volume Calculator
Calculate volume and surface area of a torus (doughnut shape).
Time & Motion
View all →Speed Calculator
Calculate average speed from distance and time.
Distance Calculator
Calculate distance from speed and time.
Time Calculator
Calculate time required from distance and speed.
Work Hours Calculator
Calculate hours worked between two times, subtracting break duration.
Days Between Dates Calculator
Calculate the number of days, weeks, months, and years between two dates.
Time Zone Converter
Convert a date/time from one time zone to another.
Physics
View all →Acceleration Calculator
Calculate acceleration from initial velocity, final velocity, and time.
Force Calculator
Calculate force from mass and acceleration using Newton's second law.
Kinetic Energy Calculator
Calculate the kinetic energy of a moving object.
Potential Energy Calculator
Calculate gravitational potential energy at a given height.
Work Done Calculator
Calculate work done by a constant force over a displacement.
Density Calculator
Calculate density from mass and volume.
Pressure Calculator
Calculate pressure from force and area.
Electrical Power Calculator
Calculate electrical power from voltage and current.
Ohm's Law Calculator
Solve for voltage, current, or resistance given any two of the three.
Weight Calculator
Calculate weight (gravitational force) from mass and gravitational acceleration. Includes presets for planets.
Momentum Calculator
Calculate the linear momentum of a moving object.
Impulse Calculator
Calculate impulse from force × time, and the resulting change in momentum.
Universal Gravitation Calculator
Calculate the gravitational force between two masses using Newton's Law of Universal Gravitation.
Escape Velocity Calculator
Calculate the minimum speed needed to escape a celestial body's gravitational pull.
Orbital Period Calculator (Kepler's 3rd Law)
Calculate the orbital period of a satellite or planet using Kepler's 3rd law.
Projectile Motion Calculator
Calculate range, max height, and flight time for a projectile launched with given speed and angle.
Pendulum Period Calculator
Calculate the period of a simple pendulum (small-angle approximation).
Simple Harmonic Motion Calculator
Calculate period, frequency, and angular frequency for a spring-mass system in simple harmonic motion.
Engineering
View all →Concrete Volume Calculator
Calculate the volume of concrete needed for slabs, footings, or columns. For quantity estimation only — not structural design.
Simple Beam Deflection Calculator (Point Load, Center)
Estimate deflection at the midspan of a simply-supported beam with a centred point load. Educational use — not for design.
Brick Quantity Calculator
Estimate the number of bricks needed for a wall, including a mortar and wastage allowance.
Business
View all →Profit Margin Calculator
Calculate gross profit and profit margin from revenue and cost.
Break-even Calculator
Calculate the number of units required to cover all fixed and variable costs.
Conversion Rate Calculator
Calculate conversion rate from visitors and conversions.
Markup Calculator
Calculate markup percentage and selling price from cost.
Commission Calculator
Calculate commission earned on sales at a given rate.
Revenue Calculator
Calculate revenue from price and quantity sold.
Revenue Impact Calculator
See the combined impact of price and volume changes on revenue.
Price Change Impact Calculator (with Elasticity)
Project the impact of a price change on volume, revenue, and profit using price elasticity of demand.
Marketing Spend Impact Calculator
Project the revenue and profit impact of additional marketing spend at an expected ROAS.
CAC Impact Simulator
Model the financial impact of reducing your Customer Acquisition Cost. Calculates LTV/CAC ratio change and payback period improvement.
LTV Growth Simulator
Simulate the impact of churn reduction and ARPU improvement on customer Lifetime Value.
Property
View all →Rental Yield Calculator
Calculate gross and net rental yield on an investment property.
Buy vs Rent Calculator
Compare the total cost of buying vs renting the same property over a chosen time horizon.
Property ROI Calculator (Advanced)
Advanced investment property return analysis — cashflow, capital gain, cash-on-cash, total ROI.
Mortgage Stress Test Calculator
Test loan affordability if interest rates rise. Standard APRA-style assessment.
Property Cashflow Simulation
Project annual cashflow, mortgage paydown, and equity growth for an investment property over time.