All Calculators

401(k) Early Withdrawal Calculator

Estimate how much you actually keep after taking an early 401(k) withdrawal — the 10% penalty, federal income tax, state tax, and lost long-term growth.

401(k) Retirement Calculator

Project your 401(k) balance at retirement using your salary, contribution rate, employer match, and expected return.

Auto Loan Calculator

Calculate your monthly car payment, total interest, and total cost for any auto loan — new or used.

Compound Interest Calculator

See how savings, a 401(k), IRA, or brokerage account grows with compound interest and monthly contributions.

Credit Card Payoff Calculator

See how many months it takes to pay off a credit card balance and how much interest you will pay at your chosen monthly payment.

Forex Pip / Lot Size / Margin Calculator

Calculate pip value, optimal lot size, and required margin for any forex trade. Built for retail forex traders managing risk per trade.

Income Tax Calculator

Estimate your 2025 federal income tax, effective rate, and marginal bracket from taxable income and filing status.

Loan Calculator with Interest

Calculate monthly payment, total interest, and total cost for any loan — personal, student, business, RV, or anything else with a fixed rate and term.

Mortgage Calculator

Estimate your monthly mortgage payment, total interest, and total cost for any home loan amount, rate, and term.

Mortgage Extra Payment Calculator

See how making extra mortgage payments shortens your loan and slashes total interest. Compare monthly extra, yearly lump sum, or one-time prepayment scenarios.

Rent vs Buy Calculator

Compare the total cost of renting versus buying a home over a chosen time horizon.

Sales Tax Calculator

Calculate U.S. sales tax on any purchase — or work backwards from the total to find the pre-tax amount.

Savings Calculator with Interest

See how a savings goal grows with monthly contributions and compound interest. Includes a year-by-year breakdown of your balance, total deposits, and interest earned.

Savings Goal Calculator

Calculate the monthly amount you need to save to hit a financial goal by a target date.

Simple Interest Calculator

Calculate simple interest on a loan, CD, or short-term note — principal, rate, and time with no compounding.

Take-Home Paycheck Calculator

Convert your gross salary to take-home pay after federal tax, FICA, state tax, and 401(k) contributions.

Tip Calculator

Calculate a fair tip at restaurants, bars, and for services — and split the bill evenly among any number of people.

Baby Formula Feeding Calculator

Estimate how many ounces of formula your baby needs each day and per feeding, based on weight and age. Includes typical feeding-interval guidance.

BMI Calculator

Calculate your Body Mass Index (BMI) from your height and weight in U.S. or metric units.

Body Fat Calculator

Estimate body fat percentage using the U.S. Navy method — just a tape measure, your height, and a few body circumferences.

Body Shape Calculator

Determine your body shape — apple, pear, hourglass, rectangle, or inverted triangle — from bust, waist, and hip measurements.

Calorie Calculator

Estimate your daily calorie needs (TDEE) based on age, sex, height, weight, and activity level — using the Mifflin-St Jeor equation.

Ideal Weight Calculator

Find your ideal body weight using four classic medical formulas: Robinson, Miller, Devine, and Hamwi.

Macro Calculator

Calculate your daily protein, carbs, and fat targets based on your goal — cutting, maintenance, or bulking — using TDEE and popular macro splits.

Pregnancy Due Date Calculator

Estimate your baby's due date from your last menstrual period (LMP) using Naegele's rule — the standard OB/GYN method in the U.S.

Algebra Equation Solver

Solve linear, quadratic, and 2-equation systems with full step-by-step working. Supports ax + b = c, ax² + bx + c = 0, and {ax+by=c, dx+ey=f}.

Distance Formula Calculator

Find the straight-line distance between two points in the coordinate plane — uses the Pythagorean-derived distance formula.

Exponent Calculator

Calculate any base raised to any power — including negative, fractional, and decimal exponents. Get the result, scientific notation, and explanation.

Fraction Calculator

Add, subtract, multiply, or divide two fractions. Get a simplified fraction, mixed number, and decimal.

GCF and LCM Calculator

Find the greatest common factor (GCF) and least common multiple (LCM) of any set of integers.

Logarithm Calculator

Compute log_b(x) for any base — common log (base 10), natural log (base e), or any custom base. Includes change-of-base details.

Midpoint Calculator

Find the midpoint of a line segment between two points (x₁, y₁) and (x₂, y₂) — averages the x and y coordinates separately.

Percentage Calculator

Quickly calculate X% of Y, what percentage one number is of another, or the percentage change between two values.

Pythagorean Theorem Calculator

Solve a² + b² = c² for any missing side — find the hypotenuse from two legs, or a leg from the hypotenuse and one leg.

Quadratic Equation Solver

Solve any quadratic equation ax² + bx + c = 0. Get both roots — real or complex — and see the discriminant and vertex.

Ratio Calculator

Simplify ratios and solve proportions — find the missing term in A:B = C:D for cooking, scaling recipes, maps, and mixing ratios.

Slope Calculator

Find the slope of a line through two points — plus the y-intercept, the slope-intercept form (y = mx + b), and the angle of inclination.

Square Root Calculator

Find the square root, cube root, or any nth root of a number — with simplified radical form for whole-number radicands.

Standard Deviation Calculator

Compute mean, variance, and standard deviation of a list of numbers — both sample (n−1) and population (n) versions.

Statistics Calculator

Enter any set of numbers to find the mean, median, mode, range, variance, and standard deviation.

TI-84 Calculator

A free online TI-84 style scientific calculator. Evaluate any expression — trig, logs, roots, exponents, and parentheses — instantly.

Age Calculator

Calculate exact age in years, months, weeks, days, hours, and minutes from any date of birth — or how old you will be on any future date.

Date Add / Subtract Calculator

Add or subtract years, months, weeks, or days from any date to find the resulting calendar date.

Date Difference Calculator

Find the exact number of years, months, weeks, and days between any two dates.

Days Until Date Calculator

Countdown to any future date — days, weeks, months, and total hours remaining until a birthday, holiday, wedding, or deadline.

Time Duration Calculator

Calculate duration between two times — hours, minutes, and total minutes. Handles times that cross midnight.

Working Days Calculator

Count the number of business days (Mon–Fri) between two dates — project deadlines, invoice due dates, vacation planning.

Area Converter

Convert between square feet, square meters, square yards, square inches, acres, hectares, and more.

Length Converter

Convert between inches, feet, yards, miles, millimeters, centimeters, meters, and kilometers.

Speed Converter

Convert speed between miles per hour, kilometers per hour, meters per second, feet per second, and knots.

Temperature Converter

Convert between Fahrenheit, Celsius, and Kelvin instantly.

Volume Converter

Convert volume between U.S. cups, teaspoons, tablespoons, fluid ounces, pints, quarts, gallons, milliliters, and liters.

Weight Converter

Convert weight between pounds, ounces, stones, grams, kilograms, and metric tons.

Car Depreciation Calculator

Estimate how much a car has lost in value — and what it will be worth after another few years — using typical U.S. depreciation curves.

Car Lease Calculator

Estimate your monthly car lease payment from the MSRP, cap cost, residual value, money factor, and lease term.

Gas Trip Cost Calculator

Find the total fuel cost of any road trip from the trip distance, your MPG, and current gas prices.

Horsepower Calculator

Estimate engine horsepower from vehicle weight and quarter-mile trap speed using Huntington's formula — plus rough wheel-to-crank conversion.

MPG Calculator

Calculate your vehicle's miles per gallon (MPG) from the miles driven and gallons used at your last fill-up.

Tire Size Calculator

Decode a P-Metric tire size (like 225/45R17) into overall diameter, sidewall, circumference, and revolutions per mile — and compare two sizes.

Concrete Calculator

Calculate how many cubic yards and 80-lb bags of concrete you need for a slab, footing, patio, or column.

Drywall Calculator

Estimate how many drywall sheets, screws, joint tape, and compound you need for a room — based on total wall and ceiling area.

Mulch Calculator

Figure out how many cubic yards or bags of mulch you need for any garden bed — by length, width, and depth.

Paint Calculator

Find out how many gallons of paint you need for a room — walls, ceiling, and trim — including doors and windows subtracted.

Roofing Calculator

Estimate total roof area, number of squares, bundles of shingles, and underlayment rolls — adjusted for roof pitch.

Tile Calculator

Calculate how many tiles and boxes you need for a floor or wall, with built-in waste allowance for cuts and breakage.

CFA Level 1 Financial Calculator

CFA-style time-value-of-money, NPV, and IRR calculator. Solves for any of N, I/Y, PV, PMT, FV given the others — using CFA Institute conventions.

Class Attendance Calculator

Track your class attendance percentage and see how many more classes you can miss while staying above a required threshold.

Cumulative GPA Calculator

Combine your existing cumulative GPA with a new semester's GPA to see your updated overall GPA — weighted by credit hours.

Final Grade Calculator

Find out what grade you need on your final exam to earn a target course grade.

GPA Calculator

Calculate your unweighted GPA from course grades and credit hours, on the standard U.S. 4.0 scale.

Reading Time Calculator

Estimate how long a text will take to read — adjustable for silent reading, reading aloud, or speed reading.

SAT to ACT Score Converter

Convert SAT total scores to ACT composite (and back) using the College Board / ACT official concordance table.

Test Score Calculator

Convert the number of correct answers on a test into a percentage and U.S. letter grade.

Typing Speed Calculator

Calculate gross WPM, net WPM (adjusted for errors), and accuracy percentage from words typed, time elapsed, and error count.

Word Count to Page Count Calculator

Convert a word count to an estimated page count for essays, reports, and manuscripts — for any common font and line spacing.

Bread Hydration Calculator

Calculate baker's percentages and hydration ratio for bread recipes. Enter flour, water, salt, and yeast weights to see standard baker math.

Butter Stick Calculator

Convert butter between U.S. sticks, tablespoons, ounces, cups, and grams. The U.S. stick is 1/2 cup or 8 tablespoons or 113 grams.

Cake Pan Converter

Convert a recipe written for one pan size to a different pan. Enter original and new pan dimensions; get a scale factor for ingredient adjustment.

Cooking Time by Weight Calculator

Estimate roasting time for beef, pork, chicken, or turkey based on weight and target doneness — using standard time-per-pound guidelines.

Cup to Gram Converter

Convert U.S. cup measurements to grams for common baking ingredients — flour, sugar, butter, milk, oil, and more.

Oven Temperature Converter

Convert oven temperatures between Fahrenheit, Celsius, and British Gas Mark. Includes fan-oven adjustment.

Recipe Scale Calculator

Scale any recipe up or down — multiply every ingredient amount by your serving ratio. Works for cups, grams, ounces, and tablespoons.

Recipe Yield Calculator

Convert between total recipe weight, servings, and per-serving size. Useful for meal prep, portioning, and nutrition labeling.

Yeast Conversion Calculator

Convert between fresh, instant, and active dry yeast. Includes amount adjustment when substituting one type for another.

Currency Converter

Convert any amount between currencies using a manual exchange rate. Useful for trip budgeting and quick conversions abroad.

Flight Time Calculator

Estimate flight duration from distance and average aircraft cruise speed. Add headwind/tailwind for more accurate planning.

Hotel Cost vs Airbnb Calculator

Compare total trip cost between a hotel and an Airbnb (or VRBO), accounting for nightly rate, fees, taxes, and meal savings from a kitchen.

Jet Lag Recovery Calculator

Estimate how many days it will take to recover from jet lag based on time zone difference and direction of travel.

Layover / Connection Time Calculator

Check whether your connection time is enough — accounting for arrival type (domestic/international), terminal change, and whether you need to clear customs.

Luggage Weight Estimator

Sum your packed luggage weight and check against airline limits — including overweight bag fees by major U.S. airline.

Mileage / Points Value Calculator

Calculate the cents-per-point value of using miles or points for a flight or hotel — and decide whether to redeem or pay cash.

Time Zone Converter

Convert a time from one zone to another. Handles common U.S. and international time zones with daylight-saving aware UTC offsets.

Trip Budget Calculator

Plan a trip budget by daily category — lodging, food, transport, activities — and see total cost with a buffer.

Bandwidth Calculator

Calculate bandwidth needs for video streaming, downloads, or office connectivity. Convert between Mbps, MB/s, and GB per hour.

Base64 String Length Calculator

Estimate Base64-encoded string length from raw byte count. Useful for sizing API payloads and storage estimates.

Binary, Decimal, Hex Converter

Convert numbers between binary (base 2), decimal (base 10), hexadecimal (base 16), and octal (base 8).

Color Hex / RGB Converter

Convert between hex color codes (#FF5733) and RGB triplets (255, 87, 51). Includes HSL representation and color preview.

Data Storage Converter

Convert between bytes, kilobytes, megabytes, gigabytes, and terabytes — using both decimal (1000) and binary (1024) bases.

File Size Estimator (Video/Image)

Estimate file size for video and image files based on resolution, bitrate, duration, or compression quality.

IP Subnet Calculator

Calculate network address, broadcast address, host range, and number of usable hosts for any IPv4 CIDR block.

Password Strength Checker

Estimate password entropy and crack time. Built for educational illustration; do not enter real passwords here.

Unix Timestamp Converter

Convert between Unix timestamps and human-readable dates. Supports seconds and milliseconds.

Acceleration Calculator

Calculate acceleration from initial velocity, final velocity, and time. Plus distance traveled.

Density Calculator

Calculate density (ρ = m/V), mass, or volume. Convert between g/cm³, kg/m³, and lb/ft³.

Force Calculator (F = ma)

Calculate force, mass, or acceleration using Newton's second law: F = m × a.

Ideal Gas Law Calculator

Solve PV = nRT for any one variable. Useful for chemistry, engineering, and atmospheric science.

Molarity Calculator

Calculate molarity (mol/L) from moles and volume, or required moles/grams for a target solution.

Ohm's Law Calculator

Calculate voltage, current, resistance, or power using Ohm's law: V = I × R and P = V × I.

pH Calculator

Calculate pH from hydrogen ion concentration, or compute [H⁺] and [OH⁻] from a known pH.

Velocity Calculator

Calculate velocity, distance, or time using v = d/t. Convert between m/s, km/h, mph, and knots.

Wave Frequency / Wavelength Calculator

Calculate wavelength, frequency, or wave speed using v = f × λ. Light, sound, and any wave phenomenon.

Break-Even Calculator

Calculate the units or revenue needed to cover fixed costs and reach break-even.

Customer Acquisition Cost Calculator

Calculate CAC from total sales and marketing spend divided by new customers acquired.

Discount Calculator

Calculate discounted price from original price and discount percentage, or determine the discount from price difference.

Employee Cost Calculator

Calculate true employee cost — salary plus benefits, taxes, and overhead.

Inventory Turnover Calculator

Calculate inventory turnover ratio and days of inventory on hand.

Lifetime Value (LTV) Calculator

Calculate customer lifetime value from average revenue, retention, and lifetime length.

Markup Calculator

Calculate selling price from cost and markup percentage, or determine markup from cost and selling price.

Profit Margin Calculator

Calculate gross, operating, and net profit margins. Compare profitability across businesses or product lines.

ROI Calculator

Calculate return on investment as a percentage and dollar gain from investment cost and final value.

Cat Age in Human Years Calculator

Convert your cat's age to human years using veterinary research-based formulas.

Cat Food Portion Calculator

Calculate daily food portions for your cat based on weight, activity, and life stage.

Dog Age in Human Years Calculator

Convert your dog's age to "human years" using the modern AVMA-recommended formula.

Dog Calorie Calculator (Treats)

Stay under the 10% treat-calorie rule. Calculate maximum daily treat calories from total daily intake.

Dog Food Portion Calculator

Calculate daily food portions for your dog based on weight, activity level, and life stage.

Dog Walking Distance Calculator

Calculate appropriate walking distance for your dog based on age, breed size, and fitness level.

Fish Tank Volume Calculator

Calculate aquarium volume in gallons or liters from tank dimensions. Plus stocking estimate.

Pet Food Cost Calculator

Estimate monthly and yearly pet food cost from daily portion size and bag price.

Pet Vaccination Cost Calculator

Estimate annual vet costs for routine care — vaccinations, checkups, flea/tick, dental.

Cap Rate Calculator

Calculate the capitalization rate for any rental property — annual NOI divided by purchase price. The standard valuation metric for income real estate.

Down Payment Calculator

How much do you need to save for a down payment? Calculate by target home price, percent down, and timeline.

Fix and Flip Profit Calculator

Estimate net profit on a flip — purchase price, repairs, holding costs, and resale minus all costs. Includes 70% rule benchmark.

House Affordability Calculator

How much house can you afford? Uses the 28/36 rule and your income, debts, down payment, and rate to show your max purchase price.

Property Tax Calculator

Estimate annual property tax from assessed value and millage (or tax rate). Includes common exemptions.

Rental Yield Calculator

Calculate gross and net rental yield for any property. Quick check on whether a rental purchase makes financial sense.

Cycling Speed Calculator

Calculate average cycling speed and finish time from distance and ride time. Or find finish time given target average speed.

Heart Rate Zones Calculator

Calculate your maximum heart rate and the five training zones (Zone 1-5) using the Tanaka formula and percent-of-max method.

Marathon Pace Calculator

Find your required marathon pace per mile and per kilometer to hit a target finish time. Includes split markers at 5K, 10K, half, and 30K.

Race Time Predictor

Predict your race time at a different distance from a recent result. Uses the Riegel formula, the standard predictor for endurance running.

Running Pace Calculator

Calculate your running pace per mile or per kilometer from total time and distance. Or work backward — find finish time given a target pace.

Swimming Pace Calculator

Calculate swim pace per 100m or per 100 yards from total time and distance. Convert between yards and meters automatically.