Math Tools
Do math faster: algebra, geometry, statistics and conversions with accurate calculators and clean visualizations for maximum efficiency.
Calculators 97
Engineering Calculators 33
ADA ramp calculator
Wheelchair ramp calculator for 2010 ADA Standards & IBC/A117.1: slope percent, length, landings, handrail length, and 1:8/1:10 alteration compliance.
Area calculator
Area & square footage calculator for rectangle, circle, triangle and more. Add a waste factor and unit price to estimate material quantity and total cost.
Asphalt calculator
Asphalt calculator for driveways, roads and parking lots: estimate hot mix tonnage, cubic yards, metric tonnes, aggregate base and total cost by area and thickness.
BTU calculator
Free air conditioner size calculator: find how many BTU you need by room size, then convert BTU to tons & kW with cooling/heating modes.
Beam load calculator
Compute maximum deflection, bending moment and shear force for simply supported and cantilever beams under point or distributed loads. Free for engineers.
Brick calculator
Free brick calculator: bricks per m2, mortar bags and waste for any wall. Deducts door and window openings for an accurate brickwork estimate.
CFM calculator
ASHRAE 62.1 CFM calculator for HVAC fan & duct sizing. Compute air flow from room size, air changes, or BTU load with altitude density correction & L/s output.
Concrete calculator
Concrete calculator for slabs, columns, footings, curb and stairs. Get cubic yards, m3, 60/80 lb bag counts and the M20 mix ratio take-off.
Drywall calculator
Drywall calculator: estimate 4x8/4x10/4x12 sheets, sheet weight, screws, tape and compound for walls and ceilings, with 5/8" Type X fire-rated guidance.
Duct size calculator
Duct size calculator for HVAC: get round or rectangular dimensions, equivalent round diameter, friction loss per 100 ft, and an ASHRAE velocity check.
FAR & lot coverage calculator
Calculate Floor Area Ratio (FAR/FSI/FSR), chargeable buildable area, lot coverage and minimum open space for zoning compliance. For architects and planners.
Flow rate calculator
Flow rate and pipe sizing calculator for volumetric flow, velocity and pipe area. Convert m³/h, L/min, GPM, CFM and check velocity against code limits.
Gear ratio calculator
Free gear ratio calculator: output RPM, torque multiplication, compound trains, plus AGMA service factor and gearbox sizing for motor reduction drives.
Grade calculator
Grade calculator with slope ratio (V:H) and code-compliance pass/fail. Compute grade percent, angle and ratio against ADA, AASHTO and drainage limits.
Gravel calculator
Free gravel calculator: find how much gravel you need for a driveway or path in cubic yards, tons and bags, plus the total cost with a waste/compaction margin.
Insulation calculator
Estimate insulation needed for walls, attics and ceilings. Calculate area, R-value, thickness and ballpark material cost for fiberglass, foam or cellulose.
Material weight calculator
Material weight calculator for steel, aluminum, copper and metal. Get total weight plus weight per meter and per foot for plates, bars, tubes and pipe.
Mulch calculator
Mulch calculator for landscaping: volume for rectangular, circular and triangular beds in yd³, ft³, m³, plus bags-vs-bulk cost and waste overage.
Occupant load calculator
Calculate occupant load and IBC 2021 egress: occupancy load factor, exits, stairway width, travel distance. Verify your design and Certificate of Occupancy.
Paint calculator
Paint calculator with spread rate, two coats and textured-surface presets. Estimate liters & gallons and the real quantity to order, not just sq ft per gallon.
Parking calculator
Parking ratio calculator: required spaces by building type, editable ITE/zoning ratio, ADA & van accessible spaces, and parking lot area estimator.
Pipe volume calculator
Pipe volume calculator: internal volume from inner diameter and length in liters/gallons, plus pipe weight per meter (empty + water-filled) for steel, PVC, copper.
Pressure drop calculator
Pressure drop calculator for pipes and ducts. Compute pressure loss for water, air and gas with Darcy-Weisbach — for HVAC, plumbing and fluid mechanics.
Pulley & belt calculator
Calculate pulley speed ratio, output RPM, belt length, wrap angle and belt speed for V-belt and flat-belt drives, with a 120-degree wrap check.
Rebar calculator
Calculate rebar quantity, length and weight for concrete slabs, then verify the steel-to-concrete ratio (kg/m³) against ACI/EC2 benchmark ranges. Free.
Refrigerant charge calculator
Estimate HVAC/AC refrigerant charge by capacity, line set length and pipe diameter, with A2L charge-limit check. R-410A, R-32, R-454B, R-22, R-134a, R-404A.
Roofing calculator
Roofing calculator: estimate roof area by pitch or angle, shingle bundles, metal panels, underlayment, ridge cap and drip edge for a pro takeoff.
Slope calculator
Slope calculator for rise over run: percent grade, angle in degrees, ratio and length. Checks ADA ramp, roof pitch X:12, driveway and pipe-fall code limits.
Square footage calculator
Square footage calculator for flooring, tile, paint and drywall. Get area in m², ft², yd², in², cm², plus waste factor, units needed and total cost.
Stair calculator
Stair calculator with IRC/IBC code pass-fail checks. Get riser count, rise, run, stringer length, pitch angle and headroom compliance for safe stair design.
Tile calculator
Tile calculator for floors and walls: estimate tiles, full boxes, thinset adhesive bags, grout bags and cost by square footage or room size, with waste.
Torque calculator
Torque calculator with bolt torque mode: reverse-solve force or lever arm, and get bolt clamp load (preload) from T = K × D × F. N·m, lb·ft, kN.
Volume calculator
Volume calculator for sphere, cone, cube, cylinder, tank, capsule, pyramid and ellipsoid. Converts m³/L/gal/ft³ and shows fill weight by density.
Financial Calculators 12
GPA Calculator
Calculate your GPA in 4.0 (US), 10.0 (Vietnam/EU) or 100-point (China/Korea) scales. Credit-weighted, Latin honors, plus true cumulative GPA carry-over.
Break-even calculator
Free break-even calculator: break-even point in units and sales, contribution margin, target profit, margin of safety and operating leverage with a chart.
Compound interest calculator
Calculate compound interest with daily to annual compounding, regular contributions, annual escalation, APY and inflation-adjusted real value.
Discount calculator
See sale price, the amount and percent you save, tax applied after the discount, and a margin guard that flags if a promo drops below cost. Free and fast.
Effective interest rate calculator
Convert nominal rate (APR) to effective annual rate (EAR/APY) for any compounding, or convert APY back to the required nominal rate. Compare loans and savings.
FIRE Number Calculator
FIRE number calculator: find how much you need to retire early, your years to FIRE from your savings rate, Coast FIRE, 25x rule and SWR bands.
GST calculator
Add or remove GST from inclusive or exclusive prices: Australia 10%, Canada 5%, India, NZ 15%, Singapore 9%. Totals reconcile to the cent for BAS and invoices.
Loan calculator
Calculate loan payments, total interest and a full amortization schedule with extra payments and APR/APY. Export the dated schedule to CSV.
Mortgage calculator
Calculate monthly mortgage payment with full PITI breakdown, amortization, auto PMI, property tax, insurance, HOA, and refinance break-even. Free and fast.
Simple interest calculator
Compute simple interest with I=P×R×T, or solve backward for the rate, principal, or time. Get interest and total amount instantly. Free online calculator.
Tip calculator
Calculate tip and split the bill per person in any currency. Round each share to clean cash, see the effective tip %, and tipping by country.
VAT calculator
Add or remove VAT, extract VAT from inclusive prices, and total Net, VAT and Gross across multiple lines. Preset 2026 rates for the UK, EU and 37 countries.
Health & Fitness 19
Child feeding calculator
Calculate infant formula and breast milk intake by age and weight, with ml per kg per day and calorie intake (kcal/kg/day) for clinical adequacy checks.
Coffee Brew
Calculate coffee-to-water ratio for V60, AeroPress, Chemex, French press, espresso, Moka pot, cold brew. Pour schedule, grind, temp, plus SCA Golden Cup TDS.
1RM calculator
Estimate your one rep max (1RM) with Epley, Brzycki and 5 more formulas, plus RPE correction and training weights for strength and hypertrophy.
BMI calculator
Find your BMI and the target healthy weight range for your height, with WHO & Asian (2004) cutoffs and waist-to-height ratio for visceral fat risk.
BMR calculator
Free BMR & TDEE calculator with Mifflin-St Jeor, Katch-McArdle and more. Get goal-based calorie targets and a protein floor in calories or kJ, metric/imperial.
BSA calculator
Compare 7 body surface area formulas (Du Bois, Mosteller, Haycock, Gehan & George, Boyd) and convert a mg/m² dose to a total dose for chemotherapy and pediatric dosing.
Baby percentile
WHO baby percentile calculator with real z-scores and SD screening. Get length, weight and head circumference percentiles for infants 0-36 months, corrected age ready.
Body fat calculator
Free body fat calculator using the U.S. Navy method. Get body fat percentage, fat mass, lean mass, ideal target by age and waist-to-height ratio risk.
Body type calculator
Free body shape calculator for women. Find your shape (hourglass, pear, rectangle, inverted triangle, triangle), with waist-hip ratio and styling tips.
Calorie calculator
Free calorie calculator: get your BMR, TDEE, daily macro split, and goal-based deficit or surplus for weight loss, gain, or maintenance.
Child BMI percentile
Free child BMI percentile and BMI z-score calculator using the CDC LMS BMI-for-age method. Get BMI, percentile, SD score, weight category and healthy range for ages 2-20.
Child calorie calculator
Child calorie calculator with Schofield BMR, TDEE and an IOM/DRI EER cross-check. Get recommended calories and macros for kids 1-18 in kg or lbs.
Cut & Bulk Macro Planner
Plan cut, maintenance and bulk phases. Mifflin-St Jeor TDEE, protein-first macros, 3-6 meal splits and training-day carb cycling. Free, metric and imperial.
Healthy weight calculator
Find your healthy weight range from height, weight and BMI, plus an optional waist-to-height ratio (WHtR) for central-fat risk. Free, instant, no signup.
Ideal weight calculator
Ideal body weight calculator with Robinson, Miller, Devine and Hamwi formulas, BMI category and adjusted body weight (ABW) for medication dosing, metric and imperial.
Lean body mass calculator
Lean body mass calculator with Boer, James & Hume formulas plus FFMI classification. Estimate LBM for clinical drug dosing, BMR and protein targets.
Macro calculator
Free IIFYM macro calculator: set protein by grams per kg or % of calories, then get carb and fat targets from your BMR and TDEE for cutting, bulking or keto.
Target heart rate calculator
Karvonen heart rate zone calculator using HRR. Find Zone 2, fat-burn, cardio and threshold targets with Standard, Tanaka and Gulati max-HR formulas.
WHO growth chart
Free WHO growth chart calculator for children 0-19. Get length/height-for-age, weight-for-age and BMI-for-age percentiles, Z-scores and WHO classifications.
HVAC Calculators 1
HVAC load calculator
Free HVAC load & BTU calculator: size AC tonnage with Manual J sensible/latent split, solar gain and an ACCA Manual S oversizing compliance check.
Math Calculators 32
Aspect Ratio Calculator
Free aspect ratio calculator. Resize images and videos by ratio, then fit into any frame with exact letterbox bars and an FFmpeg scale+pad command.
Binary calculator
Binary calculator with selectable 8/16/32/64-bit width and signed/unsigned two's complement. Add, subtract, AND, OR, XOR, NOT, shift in any base.
Combinatorics calculator
Combinatorics calculator: permutations & combinations with or without repetition, factorials, n^r, stars and bars, BigInt steps.
Complex number calculator
Add, multiply, divide complex numbers and combine parallel impedances. Rectangular to polar conversion, phasors, De Moivre powers and roots with R + jX steps.
Cosecant calculator
Calculate csc(x) in degrees or radians and solve arccsc(x) for every angle, showing the principal value, the second solution and the general solution.
Cosine calculator
Solve cos(x), arccos(x) and Law of Cosines triangles (SAS/SSS) in degrees or radians. Built for engineering, surveying and physics work.
Cotangent calculator
Cotangent calculator for cot(x), tan, csc and arccot in degrees or radians. Handles asymptotes, reciprocal and Pythagorean identities with worked steps.
Derivative & integral calculator
Differentiate or integrate a function symbolically, then evaluate the result at a point or compute a definite integral over [a, b]. Free, instant, no sign-up.
Exponent calculator
Exponent calculator for a^n: integer, fractional, negative powers, scientific notation. Exact BigInt integers, compound interest, doubling time.
Factor calculator
Free factor calculator: get all factors, factor pairs, prime factorization, divisor count, sum of divisors and perfect/abundant verdict instantly.
Factorial calculator
Exact BigInt factorial calculator for any n. Get the full integer, digit count, trailing zeros (Legendre) and Stirling magnitude, step by step.
Fraction calculator
Free fraction calculator with step-by-step working. Add, subtract, multiply, divide and simplify fractions or mixed numbers, with instant decimal and percent.
GCF calculator
GCF calculator with a step-by-step Euclidean algorithm trace and prime factorization. Find the GCF, GCD or HCF plus LCM for fraction reduction and aspect ratios.
Haversine calculator
Compute great-circle distance and initial bearing between two GPS coordinates with the haversine formula. Choose km, miles, or nautical miles.
Hex calculator
Programmer hex calculator: AND/OR/XOR/NOT, shifts and arithmetic with selectable 8/16/32/64-bit or BigInt width, two's-complement signed output, hex/dec/binary.
LCM calculator
Free LCM calculator with prime-factorization steps. Get the least common multiple plus the GCF — exact BigInt math for fractions, LCD and scheduling.
Ln calculator
Free ln(x) calculator: get natural log plus log10, log2, change of base log_b(x), and the inverse e^x (antilog). Graph included.
Log calculator
Free log calculator for any base — log₂, log₁₀, ln (natural log), custom bases, antilog and inverse log. Solve for base, argument or result with change-of-base.
Matrix calculator
Compute matrix determinant, inverse, eigenvalues, rank, trace, solve Ax=b and the condition number online. Step-by-step linear algebra for students, engineers.
Modular arithmetic calculator
Free modular arithmetic calculator: modulo, modular inverse, modular exponentiation, modular division and a linear congruence solver via extended Euclidean GCD.
Percentage calculator
Free percentage calculator with 6 modes: % of value, % change, increase/decrease, reverse %, discount and CAGR. For taxes, discounts and growth.
Polynomial solver
Find all real and complex roots of any-degree polynomials, plus a stability verdict, natural frequency and damping ratio for characteristic equations.
Quadratic equation solver
Solve ax² + bx + c = 0 with full working: real or complex roots, discriminant Δ, vertex (min/max), axis of symmetry, Vieta's formulas and factored form.
Random number generator
Free online random number generator. Pick a number in any min-max range, draw unique no-repeat samples or lists, with custom step size and delimiters.
Ratio calculator
Ratio calculator and proportion solver. Simplify ratios, convert to percentage and fraction, solve A:B = C:?, and find aspect ratios for mixing and screens.
Root calculator
Free root calculator for square, cube, and nth principal roots. Get exact perfect-power results, simplified surds (√50 = 5√2), and round-trip verification.
Scientific calculator
Free online scientific calculator with a DEG/RAD toggle for trig, log, ln, exp, factorial, parentheses, π and e. PEMDAS-aware and accurate.
Secant calculator
Free online secant calculator: get sec(x) and arcsec(x) in degrees or radians with exact values and steps. Handles asymptotes correctly (sec 90 = undefined).
Sine calculator
Compute sin(x) and arcsin(x) in degrees or radians. Unit-circle explanation, common-angle table, Law of Sines, and step-by-step examples for students and engineers.
Statistics calculator
Compute mean, median, mode, variance, standard deviation, quartiles, IQR and z-scores from any dataset. Toggle sample vs population and read skewness and kurtosis.
Tangent calculator
Compute tan(x) and arctan(x) in degrees, radians or π fractions. Convert slope to angle, grade percent and 1:N ratio, with ADA ramp-limit check.
Versine calculator
Versine calculator for versin(x), inverse versine and the sagitta (mid-ordinate) of a circular-arc curve radius. For survey, rail/road and optics layout.
Conversion 17
Area Conversion 1
All Area Units
Convert all area units instantly. Square meters, feet, acres, hectares, km², mi², mm², cm², yd² and ping in one tool. Free online converter with formulas.
Energy Conversion 1
All Energy Units
Convert all energy units instantly. Joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours, BTU, electronvolts in one tool.
Frequency Conversion 1
All Frequency Units
Convert all frequency units instantly. Hertz, kilohertz, megahertz, gigahertz, and revolutions per minute in one tool. Free converter with formulas.
Fuel Consumption Conversion 1
All Fuel Consumption Units
Convert fuel consumption units instantly. Kilometers per liter, liters per 100km, miles per gallon US and UK in one tool.
Length Conversion 7
All Length Units
Convert all length units instantly. Meters, feet, inches, centimeters, kilometers, miles, yards, millimeters in one tool.
feet to inches
Convert Feet to Inches (ft to in) instantly with our free online converter. Accurate 1 ft = 12 in formula, examples, conversion table and step-by-step...
feet to km
Convert Feet to Kilometers (ft to km) instantly with our free online converter. Accurate 1 ft = 0.0003048 km formula, examples, conversion table and...
feet to meters
Convert Feet to Meters (ft to m) instantly with our free online converter. Accurate 1 ft = 0.3048 m formula, examples, conversion table and step-by-step...
feet to miles
Convert Feet to Miles (ft to mi) instantly with our free online converter. Accurate 1 mi = 5280 ft formula, examples, conversion table and step-by-step...
feet to yards
Convert Feet to Yards (ft to yd) instantly with our free online converter. Accurate 1 yd = 3 ft formula, examples, conversion table and step-by-step...
km to feet
Convert Kilometers to Feet (km to ft) instantly with our free online converter. Accurate 1 km = 3280.84 ft formula, examples, conversion table and...
Number Conversion 1
Roman Numerals
Free Roman numeral converter. Convert decimal numbers (1–3999) to Roman numerals and back. Validates canonical form, shows the step-by-step breakdown, and explains every symbol.
Pressure Conversion 1
All Pressure Units
Convert all pressure units instantly. Pascal, bar, psi, atmosphere, mmHg, torr, kilopascal in one tool. Free converter with formulas.
Speed Conversion 1
All Speed Units
Convert all speed units instantly. Kilometers per hour, miles per hour, meters per second, knots, feet per second in one tool.
Temperature Conversion 1
All Temperature Units
Convert all temperature units instantly. Celsius, Fahrenheit, Kelvin conversions with formulas in one tool. Free converter with formulas.
Volume Conversion 1
All Volume Units
Convert all volume units instantly. Liters, gallons, milliliters, cubic meters, quarts, pints, cups in one tool. Free converter with formulas.
Weight Conversion 1
All Weight Units
Convert all weight units instantly. Kilograms, pounds, ounces, grams, tons, stones, milligrams in one tool. Free converter with formulas.
Fun Tools 2
2048 Game
Play the addictive 2048 puzzle game online. Merge tiles, reach 2048, and beat your high score. Multiple board sizes, undo moves, and statistics tracking.
Sudoku
Play Sudoku online for free. Multiple difficulty levels, hints, notes mode, and statistics tracking. Challenge your brain with the classic number puzzle game.
Geography & Mapping Tools 4
Area & Perimeter
Geodesic polygon area calculator: WGS84 lat/lon or planar survey X/Y. Land parcel area, perimeter, Shoelace centroid in hectares, acres, m².
Route Distance
Free route distance calculator: great-circle (Haversine) distance and initial bearing for multi-point GPS routes. Get km, miles, and nautical miles per segment.
Geometry Tools
GIS geometry toolkit for pros: buffer (planar), simplify via Douglas-Peucker to cut vertices, clip GeoJSON/WKT by bbox or polygon, with area & length metrics.
Polygon Calculator
Free GIS polygon area calculator: geodesic area, perimeter, centroid and edge bearings from GeoJSON/WKT or map drawing on WGS84 (EPSG:4326) lat/lon.
Time Tools 1
Time Add Subtract Calculator
Add or subtract years, months, days, hours, minutes and seconds from any date. Calendar-aware with overflow rollover, a business-days mode and ISO 8601 output.
