Trusted, formula-transparent calculators
The calculator you can
The calculator you can
actually trust
128 fast, ad-light online calculators for math, finance, health, and everyday life — each one shows the formula and step-by-step working behind the answer.
Math
22 tools Percentage Calculator — 7 Modes, Step-by-Step Work Calculate percentages 7 ways: find percent, find whole, percent change, percent difference, add/subtract percent, and reverse percent. Fraction Calculator — Step-by-Step Solver Add, subtract, multiply, divide, compare, and solve fractions with full step-by-step work. Chain up to 9 fractions, mixed numbers, simplify, and decimal conversions. Equivalent Fractions Calculator — First 100 Results Find equivalent fractions for any proper, improper, or mixed fraction. Shows the first 100 equivalent fractions instantly. Average Calculator — Mean, Median, Mode, Range, SD Calculate mean (sum divided by count), median, mode, range, and standard deviation with step-by-step work. Includes weighted average mode and a full statistics measures reference. Ratio Calculator — Simplify, Solve, Scale, Compare Simplify ratios, solve proportions, scale, split, compare, and generate equivalent ratio tables — all in one tool. Exponent Calculator — Powers, Roots, Logs, e^x Calculate powers, roots, exponentials, and logarithms. Solve xⁿ, ⁿ√x, eˣ, and log expressions with full work shown. Square Root Calculator — Simplify Radicals + Steps Calculate square roots, cube roots, and nth roots. Simplify radicals with prime factorization steps and the Babylonian method walkthrough. Quadratic Formula Calculator — Roots, Discriminant Solve quadratic equations using the quadratic formula. Find real and complex roots, discriminant, vertex, and full step-by-step solution. Scientific Calculator — Trig, Log, Exponents, Memory Full scientific calculator with trigonometry, logarithms, exponents, parentheses, and memory functions. Works on mobile and desktop. LCM Calculator — Least Common Multiple + Prime Steps Find the Least Common Multiple of two or more numbers. Shows prime factorization, GCD, and full step-by-step work. Long Division Calculator — Show Work Step-by-Step Long division with full step-by-step work shown. Get quotient, remainder, decimal, and mixed fraction results.
Roman Numeral Converter — Numbers, Dates Both Ways Convert between Roman numerals and Arabic numbers. Includes a date converter with separator support for full date strings. Mean, Median, Mode, Range Calculator — With Chart Calculate mean, median, mode, range, and geometric mean. Includes column chart visualization and sorted data display. Density Calculator — ρ = m/V, All Units, Materials Calculate density, mass, or volume using ρ = m/V. Supports multiple units with common material reference values. Molality Calculator — b = n/W, Solve Any Variable Calculate molality, solute mass, solvent mass, or molar mass. Solve b = n/W with unit conversions and a common solute reference. Mass Calculator — m = ρ × V, Density to Mass Calculate mass from density and volume (m = ρ × V). Supports multiple units with conversions and material presets. Matrix Calculator — Multiply, Inverse, Determinant Perform matrix operations: addition, subtraction, multiplication, transpose, determinant, inverse, power, and scalar multiply. Hex Calculator — Add, Subtract, Convert Hex/Dec/Bin Hex arithmetic and conversions between hexadecimal, decimal, binary, and octal. Includes bitwise operations. Slope Calculator — Steps, Graph & Line Equation Calculate slope m = (y2 − y1) / (x2 − x1) with the full step-by-step solution, visual graph, angle, distance, and line equation — from two points or a point and slope. Volume Calculator — 11 Shapes, ft³, m³, L, Gallons Calculate volumes of 11 common 3D shapes with unit conversions between cubic feet, cubic meters, liters, and gallons. Permutation & Combination Calculator — nPr, nCr Calculate permutations (nPr) and combinations (nCr) with factorial breakdown. Supports large numbers up to n=170. Circumference to Diameter — All Circle Values Convert circumference to diameter, radius, and area. Enter any circle measurement and get all others instantly.
Finance
33 tools Pay Raise Calculator — % or Flat, Hourly to Yearly Calculate your new pay after a raise — percentage, flat amount, or new rate. See hourly, weekly, monthly, and yearly breakdowns. Auto Loan Calculator — Trade-In, Tax, Amortization Calculate monthly car payments, total interest, and view amortization schedules. Factor in trade-in, down payment, taxes, and fees. 401(k) Calculator — Retirement, Match, Withdrawal Estimate your 401(k) balance at retirement, calculate early withdrawal costs, and optimize employer match contributions. Simple Interest Calculator — Solve I = Prt Any Way Calculate simple interest on loans and investments. Solve for balance, principal, rate, or term with step-by-step work. Compound Interest Calculator — Daily, Monthly, Yearly Calculate compound interest with contribution timing, cumulative breakdown, and year-by-year growth showing principal vs contributions vs interest. APY Calculator — Annual Yield from Nominal Rate Calculate annual percentage yield from a nominal interest rate and compounding frequency. Estimate future value and total interest. Cap Rate Calculator — Rental Property NOI & Yield Calculate cap rate from NOI and property value, or reverse it to find a property's value at a target cap rate. Free real estate calculator with NOI breakdown. Rule of 72 Calculator — Time to Double Investment Calculate the time or rate needed to double an investment using the Rule of 72. Shows both estimated and exact results. Future Value Calculator — FV with Periodic Deposits Calculate the future value of an investment with periodic deposits. See growth schedule with full interest breakdown. Amortization Calculator — Schedule + Extra Payments Calculate loan amortization with extra payments, principal vs interest breakdown, and annual or monthly schedules. Mortgage Calculator — Payment, Interest, Amortization Calculate monthly mortgage payments, total interest, and view amortization schedules for home loans. Mortgage Payoff Calculator — Biweekly + Extra Payments Calculate how extra payments or biweekly payments accelerate mortgage payoff and save on interest. Salary Calculator — Hourly to Yearly, Take-Home Pay Convert between salary, hourly, and monthly pay with overtime, 401(k), and health insurance deductions. See take-home across all periods. Debt Payoff Calculator — Avalanche vs Snowball Side-by-side avalanche vs snowball comparison showing interest saved and payoff timeline for each debt strategy. Loan Calculator — Payment, Extra Payment, Schedule Calculate monthly loan payments with extra payment comparison showing interest and time saved. Includes donut chart and amortization schedule. Tax Bracket Calculator 2025 — Federal + FICA + Deductions Calculate 2025 federal income tax with FICA, optional deductions (401k, HSA, itemized), and total tax burden breakdown. Take-Home Pay Calculator 2026 — Net Pay After Tax Calculate your 2026 take-home pay after federal tax, FICA, state tax, and deductions. Includes OBBB tip and overtime exemptions.
Sales Tax Calculator — Add, Reverse, By State Calculate sales tax, reverse-calculate pre-tax prices, or find the tax rate. Includes 2026 US state rates. Currency Calculator — 30+ Currencies, Live Rates Convert between 30+ currencies with live exchange rates. Includes custom rate converter and major currency cross-rate table. Credit Card Payoff Calculator — Min Payment Trap See how long to pay off credit card debt. Compare minimum vs fixed payments, and analyze balance transfer savings. Rent vs Buy Calculator — Break-Even + Investment Cost Compare renting vs buying with investment opportunity cost, PMI, HOA, equity tracking, and break-even year highlight. Retirement Calculator — How Much to Save & Withdraw Plan your retirement with 4 calculation modes. See how much to save, withdraw, and how long savings last. Rent Affordability Calculator — 30% & 40% Rules Calculate maximum affordable rent based on income, debts, and expenses. Uses the 30/40% income rules with budget breakdown. HELOC Calculator — Draw + Repayment Period Payments Calculate HELOC payments for draw and repayment periods. See total interest, amortization schedule, and compare costs. Refinance Calculator — Break-Even + Lifetime Cost Compare your current mortgage with a refinanced loan. See monthly savings, break-even point, APR, and lifetime cost. Roth IRA Calculator — Tax-Free Growth vs Taxable Estimate Roth IRA balance at retirement and compare tax-free growth vs a taxable brokerage account. Lease Calculator — Monthly Payment & Money Factor Calculate lease monthly payment or find the effective interest rate. See depreciation, money factor, and payment schedule. Boat Loan Calculator — Payment, Tax, Amortization Calculate boat loan monthly payments with down payment, trade-in, sales tax, and fees. See total cost and amortization schedule. Debt Consolidation Calculator — Side-by-Side Compare Compare existing debts against a consolidation loan. See monthly payment, total interest, and time savings side by side. Interest Rate Calculator — Solve Rate, Payment, Term Multi-solve loan calculator: find rate, payment, principal, or term from any 3 values. Includes donut chart and amortization schedule. ROI Calculator — Return on Investment + Annualized Calculate return on investment (ROI) and annualized ROI. Compare investment profitability over any time period. Savings Calculator — Compound Growth + Contributions Calculate savings growth with compound interest, periodic contributions, annual increases, and tax impact. VAT Calculator — Add, Remove, Find Rate from 2 Values Calculate VAT from any two values: rate, net price, gross price, or tax amount. Add or remove VAT instantly.
Health
21 tools Weight Loss Percentage Calculator — Track Loss kg/lb Calculate your weight loss percentage from initial and current weight. Shows total loss in pounds and kilograms. BMI Calculator — Asian Thresholds, Prime, Trefethen Calculate BMI, BMI Prime, Ponderal Index, and Trefethen BMI. Visual gauge, weight targets, and Asian-adjusted thresholds. Body Fat Calculator — U.S. Navy Tape Method Estimate your body fat percentage using the U.S. Navy method. Enter your measurements for an accurate body composition assessment. TDEE Calculator — Maintenance Calories + Macros Find maintenance calories with 3 BMR formulas plus macros for cutting or bulking. Most adults: 1,800–2,800 cal/day. Includes goal timeline. Calorie Calculator — Mifflin-St Jeor Daily Needs Calculate daily calorie needs using the Mifflin-St Jeor equation. Find calories for weight loss, maintenance, and gain. Sleep Calculator — Bedtime, Wake Time, Nap Cycles Calculate optimal bedtimes, wake times, and nap durations based on sleep cycles. Includes age-based sleep recommendations. Running Pace Calculator — Race Predictor + Splits Calculate running pace (time divided by distance) with race time prediction, training pace zones, per-mile and per-km splits, and a pace-to-finish-time chart for 5K, 10K, half, and marathon. Macro Calculator — Protein, Carbs, Fat from TDEE Calculate daily macros with built-in TDEE. Enter body stats or calories directly to get protein, carbs, and fat targets. BAC Calculator — Blood Alcohol from Drinks & Weight Estimate blood alcohol content based on drinks, weight, gender, and time elapsed. Educational use only. Period Calculator — Cycle, Ovulation, Fertile Window Track menstrual cycle and predict next period. Calculate fertile window and ovulation dates for the next 6 months. Pregnancy Calculator — Due Date from LMP or Conception Calculate pregnancy due date from LMP or conception. Track gestational age, trimesters, and milestones.
Conception Calculator — Estimate from Due Date or LMP Estimate conception date from due date, last period, or ultrasound. Includes the fertile window and full timeline. Bra Size Calculator — US, UK, EU, Australian Sizing Calculate bra size from bust and band measurements. Convert between US, UK, EU, and Australian sizing standards. Lean Body Mass Calculator — Boer, James, Hume Calculate lean body mass using Boer, James, and Hume formulas. Estimate fat-free mass from height, weight, and body fat. Body Surface Area Calculator — 8 Clinical Formulas Calculate body surface area using 8 formulas: Du Bois, Mosteller, Haycock, and more. Used for drug dosing and clinical assessments. Ideal Weight Calculator — 4 Formulas + Healthy BMI Calculate ideal body weight using Robinson, Miller, Devine, and Hamwi formulas. Compare results with healthy BMI range. BMR Calculator — Basal Metabolic Rate (Mifflin-St Jeor) Calculate your Basal Metabolic Rate using the Mifflin-St Jeor equation. See daily calorie needs for 6 activity levels. Army Body Fat Calculator — AR 600-9 Tape Test Calculate body fat using the Army tape test method (AR 600-9). Check compliance with military body composition standards. 1RM Calculator — One Rep Max + Training % Table Calculate one rep max from weight and reps. Get percentage-based training recommendations across 5 formulas. GFR Calculator — CKD-EPI 2021, MDRD, Cockcroft-Gault Estimate glomerular filtration rate using CKD-EPI 2021, MDRD, and Cockcroft-Gault. Includes pediatric Schwartz formula. Calories Burned Walking — Pace, Weight, MET-Based Calculate calories burned walking based on pace, body weight, and duration. Uses MET values from the Compendium of Physical Activities.
Everyday
27 tools Age Calculator: Your Exact Age in Years, Months, Days Calculate your exact age in years, months, and days from your date of birth. See age in weeks, hours, and total days, plus a reference table of common ages in every unit. How Old Was I Calculator — Age on Any Past Date Find out how old you were on any date. Calculate age in years, months, days, hours, minutes, and seconds. Add Times Calculator — Sum HH:MM:SS Durations Add multiple time durations together in hours, minutes, and seconds. Get results in HH:MM:SS and decimal hours. Time Until Calculator — Live Countdown to Any Date Calculate the time remaining until a specific time and date. Live countdown in days, hours, minutes, and seconds. How Many Days Until School Ends? Live Countdown Live countdown to the end of the school year showing remaining school days (weekdays) and calendar days in real time, plus a weeks-to-school-days reference and dismissal-time mode. Weeks Between Dates Calculator — Plus Days & Months Calculate the number of weeks between two dates. Also shows total days, months, weekdays, and weekend days. Inch Fraction Calculator — Decimal, Fraction, mm Convert inch fractions to decimal, decimal to fractions, and inches to metric. Supports all standard precisions. Years Ago Calculator: What Date Was X Years Ago? Calculate the exact date a specified number of years ago from any start date. Find the day of the week, weeks ago, and days ago, with full leap-year accuracy. Tip Calculator — Compare %, Split Bill, Pre-Tax Mode Calculate tips (bill times percentage) with rounding options, pre-tax tipping, service charge support, and bill splitting. Includes a 15%, 18%, and 20% tip reference table. GPA Calculator — 4.0 Scale, Cumulative, by Credit Calculate your GPA on a 4.0 scale. Add courses with grades and credit hours for an accurate cumulative GPA. Date Calculator — Days Between, Add, Business Days Calculate days between dates or add/subtract days with business day counting and US federal holiday exclusion. Discount Calculator — Sale Price, % Off, Reverse Calculate sale prices, percent off savings, and reverse-calculate original prices from discounted amounts. Hours Calculator — Time Card, Overtime, Pay Calculate work hours, overtime, and pay from your time card. Track regular and OT hours with easy daily entry. Wind Chill Calculator — NOAA Formula + Frostbite Calculate the wind chill "feels like" temperature using the NOAA formula. Includes frostbite risk estimates.
Time Calculator — Add, Subtract, Duration, Date Offset Add, subtract, and calculate time in days, hours, minutes, and seconds. Includes time expression parser and date offset calculator. Tire Size Calculator — Compare Diameter, Speedometer Compare tire sizes side by side. See differences in diameter, width, sidewall, circumference, and speedometer impact. Unit Conversion Calculator — Length, Weight, Volume, ° Convert between common units of length, temperature, area, volume, and weight in one tool. IP Subnet Calculator — IPv4, IPv6, CIDR, Broadcast Calculate IPv4 and IPv6 subnet details including network address, broadcast, host range, and CIDR notation. CIDR Calculator — Visualize IPv4 Network Ranges Interactive CIDR calculator with live binary visualization. Adjust each octet and prefix to see the netmask, base IP, broadcast, address count, and usable range instantly. Time Card Calculator — Weekly, Biweekly, OT, CSV Weekly or biweekly time card with daily/weekly overtime, break tracking, CSV export, and browser save. Ohm's Law Calculator — Volts, Amps, Ohms, Watts Calculate voltage, current, resistance, and power using Ohm's Law. Enter any 2 values to solve the other 2. Time Zone Calculator — Convert Between Any 2 Zones Convert times between time zones. Enter a date and time, select source and target zones, and see the result instantly. Resistor Calculator — Color Code, Series, Parallel Calculate resistance from color codes (4/5 band), series and parallel combinations, and conductor resistance. Electricity Calculator — kWh Cost per Appliance Estimate electricity usage and cost for any appliance. Calculate daily, weekly, monthly, and annual energy costs. Fuel Cost Calculator — Trip Gas Cost by MPG & Price Estimate fuel cost for a trip based on distance, fuel efficiency, and gas price. Horsepower Calculator — Torque, HP↔kW, Quarter Mile Calculate HP from torque × RPM ÷ 5252, convert between HP, kW, PS, and watts, or estimate engine HP from quarter-mile time and trap speed. EV Fuel Savings Calculator — Gas vs Electric Annual Compare gas vs electric vehicle fuel costs. Estimate annual savings, cost per mile, and long-term fuel savings.
Cooking
4 tools Recipe Scaler — Convert Servings + Ingredient Math Scale recipes up or down for any number of servings. Get instant ingredient conversions with imperial and metric units. Cooking Conversion Calculator — Cups, Tbsp, g, °F/°C Convert cooking measurements: cups, tablespoons, ounces, grams, and oven temperature between °F and °C. Meat Cooking Time Calculator — Roast, Grill, Slow Calculate cooking times by method (oven, grill, slow cook) with rest time and carryover guidance. Includes a per-pound roasting chart and USDA safe internal temperatures for beef, pork, chicken, turkey, and lamb. Baking Ratio Calculator — Baker's % for Bread, Cake Calculate ingredient weights using baker's percentages for bread, cake, cookies, and more.
Home
14 tools Slope Percentage Calculator — % Grade, Angle, Ratio Calculate slope percentage from rise and run, or convert between percent grade, degrees, and 1:N ratio. Includes ADA ramp, driveway, road, and drainage standards. Acreage Calculator — Land Area in Acres, Hectares Calculate land area in acres from length and width. Converts to sq ft, hectares, sq m, and more. Square Yards Calculator — Carpet, Flooring, Cost Calculate square yardage from length and width. Includes unit conversion and optional cost estimation for carpet and flooring. Square Footage Calculator — Room Area + Paint Estimate Calculate square footage for rooms and spaces. Get paint and flooring estimates from one entry. Paint Calculator — Coats, Doors, Windows, Cost Calculate paint and primer needed with custom door/window dimensions, ceiling toggle, and cost estimates. Flooring Calculator — Multi-Room with Pattern Waste Calculate flooring for multiple rooms with waste presets by pattern (straight/diagonal/herringbone) and box/carton calculator. Concrete Calculator — Slabs, Footings, Columns, Bags Calculate concrete for slabs, footings, columns, and stairways with quantity multiplier and adjustable waste factor. Get cubic yards and bag counts.
Fence Calculator — Posts, Pickets, Rails, Gates Calculate fence materials with gate support: posts, rails, pickets, concrete bags, screws, and gate hardware by fence style. Mulch Calculator — Bagged vs Bulk, 8 Materials Calculate mulch, gravel, or stone for rectangle, circle, or triangle beds. Compare bagged vs bulk cost with 8 material types and overage slider. Gravel Calculator — Cubic Yards, Tons, Driveway Calculate gravel, crushed stone, or pea gravel needed. Get cubic yards, tons, and cost estimates. Tile Calculator — Floor or Wall Coverage with Grout Calculate tiles needed for floors, walls, and surfaces. Account for grout gaps, box sizes, and total cost. BTU Calculator — AC and Heating Size by Room Calculate BTU needed for AC and heating. Estimate AC size based on room size, insulation, climate, and more. Voltage Drop Calculator — NEC Wire Sizing Calculate voltage drop for electrical wire runs. Check NEC compliance for copper and aluminum wiring. Pool Volume Calculator — Gallons by Pool Shape Calculate how many gallons of water your pool holds. Supports rectangular, circular, oval, and oblong shapes.
Education
3 tools Student Loan Calculator — Repayment Plans + Schedule Calculate student loan payments with extra payment comparison showing interest and time saved. Includes amortization schedule and 3 repayment plans. College Cost Calculator — Net Price After Aid Calculate the true cost of college after financial aid. Compare sticker price vs net price across schools. Test Grade Calculator — % Score + Letter Grade Calculate your test grade as a percentage, fraction, and letter grade from total questions and wrong answers.
Business
4 tools Profit Margin Calculator — Gross, Net, Op + Markup Calculate gross, operating, and net profit margins with markup conversion table. Includes stock trading and forex margin calculators. Break-Even Calculator — Units, Revenue, Margin Calculate break-even point in units and revenue. Understand contribution margin and fixed cost coverage. YouTube Revenue Calculator — AdSense by Niche, Views Estimate YouTube AdSense earnings based on views and niche. Understand CPM and RPM differences. CTR Calculator — Click-Through Rate, CPC, CPM Calculate click-through rate, expected clicks, required impressions, and CPC/CPM for ads, search, email, and social campaigns.