Every Calculator You Need.
100% Free.
Financial, health, math, engineering, and specialty calculators — all in one place. No watermarks. No daily limits. Instant results in your browser.
Browse by Category
Choose your calculator type
Financial Calculators
Mortgage, loans, investments, tax, retirement, and personal finance.
Mortgage Calculator
Calculate monthly mortgage payments, total interest, and full amortization schedule.
Loan Calculator
Calculate monthly loan payments and total interest for any loan type.
Compound Interest Calculator
Calculate investment growth with daily, monthly, or yearly compounding.
ROI Calculator
Calculate return on investment, profit, and annualized ROI for any investment.
Currency Calculator
Convert between 170+ currencies with live exchange rates.
Discount Calculator
Calculate sale price, discount amount, and percentage savings instantly.
Salary Calculator
Convert hourly, daily, weekly, and annual salary. Includes tax deductions.
Inflation Calculator
Calculate the real value of money adjusted for inflation over any period.
Retirement Calculator
Estimate retirement savings and how long your money will last.
Income Tax Calculator
Estimate income tax, take-home pay, and effective tax rate by bracket.
Auto Loan Calculator
Calculate monthly car payments, total interest, and total cost for any auto loan.
Interest Calculator
Calculate simple or compound interest earned on any principal amount.
Payment Calculator
Find your monthly payment for any loan given principal, rate, and term.
Amortization Calculator
Generate a full loan amortization schedule showing each payment breakdown.
Investment Calculator
Project investment returns over time with regular contributions and compounding.
Finance Calculator
Comprehensive finance calculator for loans, investments, and savings goals.
Mortgage Payoff Calculator
Calculate how extra payments shorten your mortgage and reduce total interest.
401K Calculator
Estimate your 401(k) balance at retirement with employer match and contributions.
Interest Rate Calculator
Find the interest rate needed to reach a savings or repayment goal.
Sales Tax Calculator
Calculate sales tax amount and total price for any item and tax rate.
House Affordability Calculator
Find out how much house you can afford based on income, debts, and down payment.
Savings Calculator
Calculate how much you'll save over time with regular deposits and interest.
Rent Calculator
Calculate how much rent you can afford based on your income and expenses.
Marriage Tax Calculator
Compare your tax liability before and after marriage — the marriage tax penalty.
Estate Tax Calculator
Estimate federal and state estate tax liability on an inherited estate.
Pension Calculator
Estimate your defined-benefit pension payment at retirement.
Social Security Calculator
Estimate your monthly Social Security benefit based on your earnings history.
Annuity Calculator
Calculate annuity payments for a given present value, rate, and period.
Annuity Payout Calculator
Find how long an annuity lasts or how much you receive per period.
Credit Card Calculator
Calculate interest charges and time to pay off your credit card balance.
Credit Cards Payoff Calculator
Find how long it takes to pay off credit cards at different monthly payments.
Debt Payoff Calculator
Calculate how long it takes to pay off debt with avalanche or snowball strategies.
Debt Consolidation Calculator
Compare monthly payments and total interest before and after debt consolidation.
Repayment Calculator
Calculate the monthly repayment amount and total cost for any loan.
Student Loan Calculator
Calculate student loan payments and total interest over the repayment period.
College Cost Calculator
Estimate total college costs including tuition, room, board, and fees over 4 years.
Simple Interest Calculator
Calculate simple interest earned on a principal over a set period.
CD Calculator
Calculate the maturity value of a certificate of deposit with compounding.
Bond Calculator
Calculate bond price, yield to maturity, and accrued interest.
Mutual Fund Calculator
Project mutual fund returns over time with expense ratios and compounding.
Roth IRA Calculator
Project Roth IRA balance at retirement with annual contributions and growth.
IRA Calculator
Estimate traditional IRA balance and tax savings at retirement.
RMD Calculator
Calculate Required Minimum Distributions from retirement accounts at age 73.
VAT Calculator
Add or remove VAT from any price. Supports all VAT rates worldwide.
Cash Back or Low Interest Calculator
Compare cash-back rebate offers vs. low-interest financing to find the best deal.
Auto Lease Calculator
Calculate monthly car lease payments based on MSRP, residual, and money factor.
Depreciation Calculator
Calculate asset depreciation using straight-line, declining balance, or MACRS.
Average Return Calculator
Calculate the average annual return on an investment over a specified period.
Margin Calculator
Calculate gross profit margin, markup, and net margin for any product or service.
Business Loan Calculator
Calculate monthly payments and total cost for small business loans.
Debt-to-Income Ratio Calculator
Calculate your DTI ratio — a key factor lenders use in mortgage approval.
Real Estate Calculator
Calculate home purchase costs, net proceeds from sale, and ROI on property.
Take-Home-Paycheck Calculator
Estimate your net pay after federal, state, and local taxes and deductions.
Personal Loan Calculator
Calculate monthly payments and total interest for personal loans.
Boat Loan Calculator
Calculate monthly payments and total cost for boat or marine financing.
Lease Calculator
Calculate monthly lease payments for equipment, vehicles, or property.
Refinance Calculator
Calculate refinance savings, break-even point, and new monthly payment.
Budget Calculator
Build a monthly budget and track income vs. expenses by category.
Rental Property Calculator
Calculate ROI, cash flow, cap rate, and NOI for rental properties.
IRR Calculator
Calculate the internal rate of return for a series of cash flows.
APR Calculator
Calculate the annual percentage rate for any loan including fees.
FHA Loan Calculator
Calculate FHA loan payments including MIP, down payment, and eligibility.
VA Mortgage Calculator
Calculate VA loan payments with the VA funding fee for eligible veterans.
Home Equity Loan Calculator
Calculate payments and interest for a home equity loan or second mortgage.
HELOC Calculator
Calculate monthly payments during draw and repayment periods for a HELOC.
Down Payment Calculator
Calculate the down payment needed for a home and how long to save for it.
Rent vs. Buy Calculator
Compare total costs of renting vs. buying a home over any time horizon.
Payback Period Calculator
Calculate how long it takes for an investment to recoup its initial cost.
Present Value Calculator
Calculate the present value of future cash flows given a discount rate.
Future Value Calculator
Calculate the future value of a present sum or series of payments.
Commission Calculator
Calculate sales commission earnings based on rate, sales amount, or tiers.
Mortgage Calculator UK
UK mortgage repayment calculator with stamp duty and LTV support.
Canadian Mortgage Calculator
Canadian mortgage calculator with CMHC insurance and semi-annual compounding.
Mortgage Amortization Calculator
Generate a full mortgage amortization table with principal and interest breakdown.
Percent Off Calculator
Calculate the sale price after a percentage discount and how much you save.
Fitness & Health Calculators
BMI, calories, body fat, pregnancy, nutrition, and fitness metrics.
BMI Calculator
Calculate Body Mass Index with metric and imperial support. Includes healthy range.
Calorie Calculator
Calculate daily calorie needs based on age, weight, height, and activity level.
Body Fat Calculator
Estimate body fat percentage using the US Navy method.
Due Date Calculator
Calculate pregnancy due date from last menstrual period or conception date.
Ovulation Calculator
Calculate ovulation window and fertile days from your cycle length.
BMR Calculator
Calculate Basal Metabolic Rate — calories your body burns at rest per day.
Macro Calculator
Calculate daily protein, carbohydrate, and fat targets based on your goals.
Ideal Weight Calculator
Find your ideal body weight range based on height using multiple formulas.
Pregnancy Calculator
Calculate pregnancy week, trimester, and key milestone dates.
Pregnancy Weight Gain Calculator
Calculate recommended weight gain during pregnancy based on pre-pregnancy BMI.
Pregnancy Conception Calculator
Estimate your conception date from due date or last menstrual period.
Pace Calculator
Calculate running pace, finish time, or distance for any race or training run.
Army Body Fat Calculator
Calculate body fat % using the U.S. Army tape-measurement method.
Carbohydrate Calculator
Calculate daily carbohydrate intake based on calorie goals and activity level.
Lean Body Mass Calculator
Estimate lean body mass (muscle + bone + organs) using height and weight.
Healthy Weight Calculator
Calculate the healthy weight range for your height and body frame.
Calories Burned Calculator
Estimate calories burned during any physical activity or exercise.
One Rep Max Calculator
Estimate your 1RM for any lift from submaximal reps and weight lifted.
Target Heart Rate Calculator
Calculate target heart rate zones for cardio exercise based on age and fitness.
Protein Calculator
Calculate daily protein needs based on weight, activity level, and fitness goals.
Fat Intake Calculator
Calculate daily fat intake targets for your calorie goals and dietary preferences.
TDEE Calculator
Calculate Total Daily Energy Expenditure — your total calorie burn per day.
Conception Calculator
Estimate your most likely conception date based on your due date or LMP.
Period Calculator
Predict your next period dates and cycle phases over the coming months.
GFR Calculator
Estimate glomerular filtration rate (eGFR) to assess kidney function.
Body Type Calculator
Determine your body type (ectomorph, mesomorph, endomorph) based on measurements.
Body Surface Area Calculator
Calculate body surface area in m² used for medical dosing and burn area estimation.
BAC Calculator
Estimate blood alcohol content based on drinks consumed, weight, and time.
Anorexic BMI Calculator
Understand underweight BMI categories and healthy weight restoration goals.
Weight Watcher Points Calculator
Calculate Weight Watchers SmartPoints for any food based on nutrition info.
Overweight Calculator
Check if you are overweight using BMI, waist circumference, and body fat %.
Math Calculators
Algebra, geometry, statistics, fractions, and advanced mathematics.
Scientific Calculator
Full-featured scientific calculator with trigonometry, logarithms, and exponents.
Percentage Calculator
4 modes: % of a number, % change, % difference, and reverse percentage.
Fraction Calculator
Add, subtract, multiply, and divide fractions. Simplify to lowest terms.
Triangle Calculator
Solve any triangle given sides and angles using the law of sines and cosines.
Volume Calculator
Calculate volume of sphere, cube, cylinder, cone, and other 3D shapes.
Standard Deviation Calculator
Calculate population and sample standard deviation and variance from a data set.
Random Number Generator
Generate random integers or decimals within any range you specify.
Number Sequence Calculator
Identify and continue arithmetic and geometric sequences.
Percent Error Calculator
Calculate the percent error between an experimental and theoretical value.
Exponent Calculator
Calculate base raised to any power including fractional and negative exponents.
Binary Calculator
Perform binary arithmetic and convert between binary, decimal, hex, and octal.
Hex Calculator
Add, subtract, multiply hexadecimal numbers and convert to decimal and binary.
Half-Life Calculator
Calculate radioactive decay and the remaining quantity after any number of half-lives.
Quadratic Formula Calculator
Solve quadratic equations ax² + bx + c = 0 and find real or complex roots.
Slope Calculator
Calculate slope, y-intercept, and equation of a line from two points.
Log Calculator
Calculate logarithms in any base — log₂, log₁₀, ln, and custom bases.
Area Calculator
Calculate area of rectangle, circle, triangle, and other 2D shapes.
Sample Size Calculator
Determine the minimum sample size for a statistically valid survey or experiment.
Probability Calculator
Calculate event probability, conditional probability, and Bayes' theorem.
Statistics Calculator
Calculate mean, median, mode, range, variance, and standard deviation.
Mean, Median, Mode Calculator
Find mean, median, mode, and range from any list of numbers.
Permutation and Combination Calculator
Calculate nPr and nCr — the number of permutations and combinations.
Z-score Calculator
Calculate z-score, percentile, and area under the normal distribution curve.
Confidence Interval Calculator
Calculate 95% or 99% confidence interval for a population proportion or mean.
Ratio Calculator
Simplify ratios, find equivalent ratios, and solve ratio word problems.
Distance Calculator
Calculate distance between two points using coordinates or the distance formula.
Circle Calculator
Calculate area, circumference, diameter, and radius of a circle.
Surface Area Calculator
Calculate surface area of cube, sphere, cylinder, cone, and other 3D shapes.
Pythagorean Theorem Calculator
Find the missing side of a right triangle using the Pythagorean theorem.
Right Triangle Calculator
Solve right triangles — find all sides and angles from any two known values.
Root Calculator
Calculate square root, cube root, and nth root of any number.
Least Common Multiple Calculator
Find the LCM (Least Common Multiple) of two or more integers.
Greatest Common Factor Calculator
Find the GCF (Greatest Common Factor) of two or more integers.
Factor Calculator
Find all factors and prime factors of any integer.
Rounding Calculator
Round numbers to any decimal place — nearest whole, tenth, hundredth, etc.
Matrix Calculator
Add, subtract, multiply matrices, and find determinants and inverses.
Scientific Notation Calculator
Convert numbers to and from scientific notation and perform operations.
Big Number Calculator
Perform arithmetic on very large numbers beyond standard calculator precision.
Prime Factorization Calculator
Find the prime factorization of any integer using factor trees.
Common Factor Calculator
List all common factors shared between two or more numbers.
Basic Calculator
Simple four-function calculator for quick arithmetic — add, subtract, multiply, divide.
Long Division Calculator
Perform long division step-by-step with quotient, remainder, and working shown.
Average Calculator
Calculate the arithmetic mean from a list of numbers.
P-value Calculator
Calculate the p-value from t-test, chi-square, z-score, or F-statistic.
Other Calculators
Date & time, engineering, unit conversion, and specialty calculators.
Age Calculator
Calculate exact age in years, months, days, and hours. Birthday countdown included.
Days Between Dates
Calculate days, weeks, months, and years between two dates. Business days option.
Tip Calculator
Calculate tip amount and split the bill evenly among multiple people.
GPA Calculator
Calculate GPA for semester or cumulative across all courses.
Date Calculator
Add or subtract days, weeks, months, or years from any date.
Time Calculator
Add and subtract hours, minutes, and seconds. Convert between time formats.
Hours Calculator
Calculate total hours and minutes between start and end times for any shift.
Grade Calculator
Calculate your weighted course grade or the score needed on a final exam.
Height Calculator
Predict a child's adult height based on parent heights using multiple methods.
Concrete Calculator
Calculate cubic yards of concrete needed for slabs, footings, and columns.
IP Subnet Calculator
Calculate subnet mask, network address, broadcast address, and host range.
Bra Size Calculator
Find your correct bra size in US, UK, EU, and other international sizing systems.
Password Generator
Generate strong, random passwords with custom length and character sets.
Dice Roller
Roll any number of dice with any number of sides — d4, d6, d8, d10, d12, d20.
Conversion Calculator
Convert between common units of length, weight, volume, temperature, and more.
Fuel Cost Calculator
Calculate trip fuel cost based on distance, fuel economy, and local gas prices.
Voltage Drop Calculator
Calculate voltage drop in electrical wire runs for any circuit length and load.
BTU Calculator
Calculate BTUs needed to heat or cool a room based on size and climate.
Square Footage Calculator
Calculate total square footage for rooms, floors, and irregularly shaped areas.
Time Card Calculator
Calculate total work hours and pay from daily clock-in and clock-out times.
Time Zone Calculator
Convert times between any two time zones instantly with DST support.
Love Calculator
Calculate love compatibility percentage between two names — just for fun!
GDP Calculator
Calculate GDP using the expenditure, income, or production approach.
Gas Mileage Calculator
Calculate your car's MPG, litres per 100 km, and total fuel cost per trip.
Horsepower Calculator
Convert between horsepower units: HP, kW, PS, and metric horsepower.
Engine Horsepower Calculator
Estimate engine horsepower from torque and RPM using the HP formula.
Stair Calculator
Calculate riser height, tread depth, and number of steps for any staircase.
Resistor Calculator
Calculate resistor value from color bands or find series/parallel combinations.
Ohms Law Calculator
Calculate voltage, current, resistance, or power using Ohm's Law.
Electricity Calculator
Calculate electricity costs, kilowatt-hours, and energy consumption for devices.
Shoe Size Conversion
Convert shoe sizes between US, UK, EU, CM, and other international standards.
Mileage Calculator
Calculate mileage reimbursement, trip distance, or miles driven on a route.
Density Calculator
Calculate density, mass, or volume when you know any two of the three.
Mass Calculator
Convert mass between kilograms, pounds, ounces, grams, and other units.
Weight Calculator
Convert weight units between lb, kg, stone, oz, and metric tons.
Speed Calculator
Calculate speed, distance, or time — and convert between MPH, KPH, and m/s.
Molarity Calculator
Calculate molarity, moles, volume, or molecular weight for chemistry solutions.
Molecular Weight Calculator
Calculate molecular weight (molar mass) of any chemical formula.
Roman Numeral Converter
Convert any integer to Roman numerals or decode Roman numerals to decimal.
Golf Handicap Calculator
Calculate your USGA golf handicap index from recent score history.
Sleep Calculator
Find the best bedtimes and wake times to complete full sleep cycles.
Tire Size Calculator
Compare tire sizes and calculate speedometer difference and plus-sizing impact.
Roofing Calculator
Estimate roofing materials — shingles, underlayment, and ridge cap — for any roof.
Tile Calculator
Calculate how many tiles you need for any floor or wall area including waste factor.
Mulch Calculator
Calculate cubic yards or bags of mulch needed for garden beds at any depth.
Gravel Calculator
Calculate tons or cubic yards of gravel needed for driveways, paths, and beds.
Wind Chill Calculator
Calculate the real-feel temperature based on air temperature and wind speed.
Heat Index Calculator
Calculate apparent temperature from air temperature and relative humidity.
Dew Point Calculator
Calculate dew point, relative humidity, and absolute humidity from temperature.
Bandwidth Calculator
Calculate file transfer time, bandwidth needs, or network throughput.
Time Duration Calculator
Calculate the exact duration between two times in hours, minutes, and seconds.
Day Counter
Count the number of days until or since any date — countdown or up.
Day of the Week Calculator
Find what day of the week any date falls on — past, present, or future.
Free Online Calculators — Finance, Health, Math & More
RoughTools offers 203+ professional-grade calculators, all completely free and accessible without any account or signup. Whether you need to calculate your mortgage payment before speaking to a lender, estimate your BMI before a doctor's appointment, plan your retirement savings with compound interest, or simply figure out how to split a restaurant bill fairly — every calculation you need is here and ready in seconds.
Our calculators are designed for real people making real decisions. A 28-year-old planning their first retirement contribution, a couple calculating whether they can afford a home, a student figuring out their GPA before applying to graduate school, a parent calculating a pregnancy due date — these are the people our tools are built for. No finance degree required. No confusing jargon. Just enter your numbers and get clear, accurate results.
Unlike calculator apps that require installation or accounts, browser-based calculators like ours work on any device — smartphone, tablet, or desktop — without downloading anything. They load instantly, work offline once cached, and keep your financial and health data completely private on your device.
Our calculators span five major categories. Finance calculators cover mortgages, loans, compound interest, retirement savings, tax estimation, and more — the essential tools for anyone managing their financial future. Health calculators include BMI, daily calorie needs, body fat percentage, pregnancy due date, and ideal weight — built to the same clinical standards used by healthcare providers.
Math calculators handle everything from percentages and fractions to quadratic equations and statistical analysis. Unit converters make it easy to switch between metric and imperial across length, weight, temperature, speed, area, and volume. And everyday calculators tackle tip splitting, discount pricing, GPA calculation, and date differences.
Every calculator follows these principles:
- ✓Transparent formulas — we show you the exact math
- ✓Honest disclaimers — we say when to consult a professional
- ✓100% private — no data is ever transmitted or stored
- ✓No account needed — start calculating immediately
- ✓Mobile-first design — works perfectly on any screen size
Explore other free tools:
Why Our Calculators Are Trustworthy
Transparent Formulas
Every calculator shows the exact mathematical formula it uses — not a black box. See the formula, understand the variables, verify the math yourself.
Honest Disclaimers
Finance and health calculators clearly say when results are estimates and when you should consult a professional. We never overstate what a calculator can tell you.
100% Private
No data you enter is ever transmitted to our servers, stored in any database, or shared with third parties. All calculations happen on your device only.
No Account Needed
Start calculating immediately — no email, no password, no signup form. Every tool on RoughTools is open to everyone, always, for free.