calcu.lol — Visual calculators that help you understand math
Free online calculators with visual explanations. Understand the math, not just the answer.
323 matching calculators
Everyday & Practical, 35
- Unit ConverterVisual unit conversion
- Tip & Bill SplitterSplit bills and tips instantly
- Discount CalculatorSee how much you save
- Speed / Distance / TimeD = R × T solved visually
- Age CalculatorExact age from any date
- Date DifferenceDays between any two dates
- BMI CalculatorBMI with health-zone gauge
- Fuel Cost CalculatorTrip fuel cost visualized
- Pace CalculatorPace / distance / time solver
- Sleep CalculatorWake up between sleep cycles
- Salary CalculatorPay rate converter
- TDEE / Calorie CalculatorBMR and TDEE from body stats
- Electricity Cost CalculatorPower bill estimator
- GPA CalculatorWeighted GPA from grades
- Final GradeFind the final-exam score needed to hit a target course grade
- Business DaysCount business days (Mon-Fri) between two dates
- Time DurationAdd or subtract two HH:MM:SS durations
- CountdownCount down to (or from) a target date and show days, hours, minutes
- Work Hours & Time CardTrack daily hours worked and compute weekly pay
- Unit Price & Best DealCompare price per unit across packages to find the cheapest deal
- Budget Percentage PlannerSplit a budget by percentages across categories with overage warnings
- Map Scale CalculatorConvert between map distance and real-world distance using a representative fraction
- Roof Pitch CalculatorConvert between rise/run, slope angle, and standard pitch labels
- Stair CalculatorPlan stair rise, run, and tread depth with code-friendly guidance
- Paint Coverage CalculatorEstimate gallons of paint needed for a room with deductions and coats
- Tile CalculatorEstimate tile count and boxes for a floor or wall with waste margin
- DMS Coordinate ConverterConvert latitude/longitude between decimal degrees and degrees-minutes-seconds
- Bearing & Distance CalculatorGreat-circle distance and bearing between two latitude/longitude points
- Concrete Volume & BagsVolume of slabs and columns plus bag count by yield
- Board Foot CalculatorLumber board feet and cost
- Tire Size ComparatorParse and compare tire size codes like 225/45R17 by diameter and revs
- Gear Ratio & RPMEngine RPM, gear ratio, final drive, and tire diameter into vehicle speed
- Time Zone ConverterConvert a time across IANA time zones using built-in Intl.DateTimeFormat
- Recipe ScalerScale a recipe up or down by servings, with automatic ingredient unit conversion.
- TDEE & MacrosDaily calorie needs and a macronutrient split
Finance & Money, 20
- Compound InterestWatch your money grow
- Simple InterestI = Prt, solved any way
- Loan CalculatorMonthly payments visualized
- Savings GoalTime to reach your goal
- ROI CalculatorInvestment return visualized
- Break-Even CalculatorCost vs. revenue crossover
- CAGR CalculatorCalculate compound annual growth.
- Inflation CalculatorEstimate future prices and purchasing power.
- Emergency Fund CalculatorEstimate your emergency savings target.
- Markup & Margin CalculatorMarkup vs. margin side-by-side
- Currency ConverterConvert currencies with an honest, dated rate snapshot.
- Percent Change & CAGRCalculate percent change between two values and CAGR over a number of periods
- Sales Tax & VATApply pre-tax discounts and sales tax / VAT to get the final price
- Mortgage AffordabilityEstimate the home price you can afford from income, debt, and target DTI
- Debt Payoff PlannerCompare snowball vs avalanche debt payoff strategies across multiple debts
- Rent vs Buy CalculatorCompare renting and buying total costs over a horizon with mortgage, taxes, and investment growth
- Retirement PlannerProject retirement balance from contributions and returns, plus the 4% rule annual draw
- NPV & IRR CalculatorNet present value and internal rate of return for a stream of cash flows
- Black-Scholes Option PricerEuropean option price, Greeks, and payoff diagram
- Amortization ScheduleLoan payment table with a balance curve
Math & Algebra, 94
- Basic CalculatorArithmetic operations visualized
- Rule of ThreeProportion solving made visual
- Percentage CalculatorPercentage calculations visualized
- TrigonometryInteractive unit circle
- FractionsFraction arithmetic visualized
- GCD / LCMFactor visualization
- Exponents & RootsPowers and roots visualized
- LogarithmsInteractive log curve
- StatisticsData visualization and stats
- Quadratic FormulaRoots on a live parabola
- Linear Equation / SlopeLine equation with graph
- Number Base ConverterBinary, hex, octal converter
- Combinations & PermutationsnCr and nPr visualized
- Prime FactorizationFactor tree visualized
- Sequences CalculatorArithmetic & geometric sequences
- Roman Numeral ConverterDecimal ↔ Roman numerals
- Significant FiguresSig figs identified & rounded
- Matrix CalculatorMatrix operations step-by-step
- Weighted AverageCompute a weighted mean from a list of values and corresponding weights
- Z-ScoreCompute the standard score z = (x - mean) / standard deviation
- Binomial ProbabilityBinomial probability and cumulative distribution: exactly, at most, at least k successes
- Polynomial Root FinderFind real roots of a cubic ax³+bx²+cx+d via Cardano's formula plus the discriminant
- Function GrapherPlot one or more y=f(x) with intercepts and key points
- Derivative CalculatorNumeric derivative f'(x) with a tangent line
- Integral CalculatorDefinite integral shown as shaded area under the curve
- Limit CalculatorOne- and two-sided limits, numerically and visually
- Riemann SumApproximate area with left, right, midpoint, or trapezoid rectangles
- Taylor SeriesTaylor and Maclaurin polynomial approximation of a function
- Extrema & Inflection FinderFind maxima, minima, and inflection points of a function
- Partial DerivativesPartial derivatives and gradient of f(x,y)
- Gradient & Directional DerivativeGradient vector and directional derivative of a surface
- Cubic Equation SolverReal and complex roots of a cubic ax³+bx²+cx+d
- Quartic Equation SolverRoots of a degree-four polynomial
- Polynomial GrapherGraph a polynomial with its real roots and turning points
- Polynomial Long DivisionDivide polynomials with quotient and remainder
- Long DivisionStep-by-step long division with remainder and repeating decimal
- Completing the SquareRewrite a quadratic in vertex form, step by step
- Inequality SolverSolve linear and quadratic inequalities on a number line
- Absolute Value SolverSolve absolute-value equations and inequalities
- System of Equations (2×2)Solve two linear equations with the intersection point
- System of Equations (3×3)Gaussian elimination for three unknowns
- Slope-Intercept ExplorerExplore y=mx+b as slope and intercept change
- Parametric PlotterPlot parametric curves x(t), y(t)
- Polar GrapherPlot polar curves r(θ)
- Rational Function AnalyzerAsymptotes, holes, and behavior of p(x)/q(x)
- Piecewise FunctionEvaluate and graph piecewise-defined functions
- Matrix DeterminantDeterminant with step-by-step reduction
- Matrix InverseInvert a matrix via Gauss-Jordan elimination
- Matrix Rank & NullityRank, nullity, and reduced row echelon form
- Eigenvalues & EigenvectorsEigenvalues and eigenvectors for 2×2 and 3×3 matrices
- Singular Value DecompositionFactor a matrix as U Σ Vᵀ
- QR DecompositionFactor a matrix as Q R via Gram-Schmidt
- LU DecompositionFactor a matrix as L U with partial pivoting
- Gram-Schmidt OrthonormalizationOrthonormalize a set of vectors
- Linear TransformationVisualize how a 2×2 matrix transforms the plane
- Row Reduction (RREF)Reduce a matrix to row echelon form, step by step
- Complex Number CalculatorArithmetic, modulus, and argument on an Argand diagram
- Complex Powers (De Moivre)Powers and roots of complex numbers
- Roots of UnityThe n nth-roots of unity on the unit circle
- Quaternion CalculatorQuaternion arithmetic for 3D rotation
- Mandelbrot ExplorerZoom into the Mandelbrot set
- Julia Set ExplorerRender Julia sets for any complex parameter
- Unit Circle ExplorerAngles and trig values around the unit circle
- 3D Vector CalculatorDot, cross, magnitude, and angle for 3D vectors
- Extended Euclidean AlgorithmGCD with Bézout coefficients
- Modular ArithmeticMod, modular inverse, and properties
- Modular ExponentiationFast aᵇ mod m by repeated squaring
- Chinese Remainder TheoremSolve simultaneous congruences
- Euler's Totient φ(n)Count integers coprime to n
- Diophantine SolverInteger solutions of ax+by=c
- Collatz Conjecture3n+1 trajectory length and step plot
- Sieve of EratosthenesVisualize the primes up to n
- Divisors, τ(n) & σ(n)Divisor list, count, and sum of divisors
- Continued FractionExpand a number and its best rational approximations
- Pascal's TriangleBinomial coefficients in Pascal's triangle
- Magic SquareGenerate and validate magic squares
- Graph ColoringColor a graph with as few colors as possible
- Sudoku SolverSolve any Sudoku puzzle
- Fourier SeriesApproximate a periodic function with harmonics
- FFT CalculatorDiscrete Fourier transform and frequency spectrum
- Normal DistributionBell curve PDF and CDF with shaded probabilities
- t-DistributionStudent's t PDF, CDF, and critical values
- Chi-Square DistributionChi-square PDF, CDF, and critical values
- F-DistributionF PDF, CDF, and critical values
- Poisson DistributionPMF and CDF for rare-event counts
- Binomial DistributionPMF and CDF for n independent trials
- Hypergeometric DistributionSampling without replacement
- Confidence IntervalConfidence interval for a mean or proportion
- Sample SizeSurvey sample size or margin of error for a proportion
- Hypothesis Testz- and t-tests with p-value and rejection region
- Bayes' TheoremPosterior probability with a tree diagram
- Correlation & RegressionLeast-squares line with r and R²
- Monte Carlo SimulatorEstimate π and integrals by random sampling
- Monty Hall SimulatorStay vs switch, simulated and exact
Geometry & Shapes, 25
- Triangle SolverVisual triangle solving
- Circle CalculatorCircle measurements visualized
- Area & PerimeterShape area & perimeter
- Volume Calculator3D shape volume & surface area
- Pythagorean TheoremRight triangle solver
- Coordinate Distance & MidpointDistance & midpoint on a grid
- Regular Polygon CalculatorAny regular polygon
- Ellipse CalculatorCalculate ellipse area, circumference approximation, eccentricity, and foci
- Trapezoid CalculatorSolve trapezoid area, height, bases, median, and perimeter
- Circle Sector CalculatorCalculate sector area, arc length, chord length, and perimeter
- Arc Length CalculatorSolve arc length, radius, or angle for a circular arc
- Conic Section AnalyzerClassify and graph a conic from its equation
- Hyperbola PropertiesFoci, vertices, and asymptotes of a hyperbola
- Parabola Focus & DirectrixFocus, directrix, and vertex of a parabola
- 3D Distance & MidpointDistance and midpoint between two 3D points
- Plane from 3 PointsPlane equation and normal vector from three points
- Line-Plane IntersectionWhere a line meets a plane in 3D
- Rotation Matrix2D and 3D rotation matrices from angles
- Point in PolygonRay-casting point-in-polygon test
- Convex HullConvex hull of a set of points
- Voronoi DiagramVoronoi regions for a set of points
- Sphere & Solid GeometrySurface area and volume of spheres, cones, and cylinders
- Platonic SolidsFaces, edges, vertices, area, and volume of regular solids
- Delaunay TriangulationTriangulate a set of points (dual of Voronoi)
- 2D Vector CalculatorAdd, subtract, and project 2D vectors
Science & Physics, 28
- Ohm's LawV = I × R visualized
- Kinematics CalculatorMotion equations visualized
- Density CalculatorMass, volume, density
- Newton's Second LawF = m × a visualized
- Half-Life CalculatorRadioactive decay curve
- Ideal Gas LawPV = nRT with piston visual
- Resistor Color CodeDecode resistor color bands and reverse lookup standard color codes
- Voltage DividerSolve resistor divider voltage, input, and resistor values
- Series & Parallel Resistor CalculatorEquivalent resistance in series or parallel
- RC Time ConstantCalculate RC time constants and charge or discharge curves
- Projectile Motion CalculatorCalculate projectile flight time, range, height, and velocity components
- Work Energy Power CalculatorCalculate work, kinetic energy, potential energy, and power
- Waves CalculatorSolve wave speed, frequency, wavelength, and period
- Molarity CalculatorCalculate molarity, moles, or volume from the concentration formula C = n/V
- Dilution CalculatorSolve dilution problems with C₁V₁ = C₂V₂ for any unknown variable
- Molar Mass CalculatorCalculate molar mass from a molecular formula like H2O, NaCl, or C6H12O6
- Simple Harmonic MotionPosition, velocity, and acceleration of an oscillator
- Damped OscillationUnder-, critically-, and over-damped motion
- Wave SuperpositionAdd waves to see interference and beats
- Beat FrequencyBeats produced by two close frequencies
- PendulumPeriod of a simple pendulum
- Doppler EffectFrequency shift for a moving source or observer
- Snell's LawRefraction angle and critical angle with a ray diagram
- Thin Lens & MirrorImage distance, magnification, and ray diagram
- Gravitational ForceNewton's law of universal gravitation
- Orbital & Escape VelocityOrbital period, circular velocity, and escape velocity
- pH / pOH CalculatorpH, pOH, [H⁺], and [OH⁻] with an acidity scale
- Chemical Equation BalancerBalance chemical reactions via linear algebra
Tech & Digital, 18
- Download Time CalculatorHow long will it take?
- File Size ConverterBytes ↔ KB ↔ MB ↔ GB ↔ TB
- Color Code ConverterHEX ↔ RGB ↔ HSL ↔ HSV
- Aspect Ratio CalculatorScale & reduce dimensions
- Screen PPI CalculatorPixels per inch from resolution
- Password EntropyPassword strength in bits
- Base64 Encode & DecodeEncode text to base64 and decode base64 back to text
- URL EncoderPercent-encode and decode URLs and query strings
- Unix TimestampConvert between Unix epoch seconds and ISO 8601 datetimes
- Hash & ChecksumGenerate SHA-1, SHA-256, SHA-384, and SHA-512 digests of text
- JSON FormatterFormat, validate, and minify JSON with helpful error messages
- Color Contrast CheckerCheck WCAG AA/AAA contrast ratio between two colors
- CSS ClampGenerate responsive CSS clamp() values for fluid typography
- DPI & Print SizeCompute pixel size, print size, and image resize math
- Regex TesterTest JavaScript regular expressions against sample text with match groups
- QR Code GeneratorGenerate styled QR codes from text or URLs with PNG and SVG download.
- RSA DemonstratorEducational RSA key generation, encryption, and decryption
- IP Subnet CalculatorIPv4 CIDR network, broadcast, and host range
Unit Converters, 103
- Celsius to Fahrenheit°C to °F converter
- Fahrenheit to Celsius°F to °C converter
- Celsius to Kelvin°C to K converter
- Fahrenheit to Kelvin°F to K converter
- cm to Inchescm to in converter
- Inches to cmin to cm converter
- km to Mileskm to mi converter
- Miles to kmmi to km converter
- Feet to Metersft to m converter
- Meters to Feetm to ft converter
- mm to Inchesmm to in converter
- Inches to Feetin to ft converter
- Inches to MillimetersConvert inches to millimeters.
- Yards to Metersyd to m converter
- Feet to cmft to cm converter
- Meters to kmm to km converter
- Nautical Miles to MilesNM to mi converter
- Meters to Yardsm to yd converter
- cm to Feetcm to ft converter
- kg to lbskg to lbs converter
- lbs to kglbs to kg converter
- Ounces to Gramsoz to g converter
- Grams to Ouncesg to oz converter
- kg to Stonekg to st converter
- Stone to KilogramsConvert stone to kilograms.
- Tons to kgt to kg converter
- mg to Gramsmg to g converter
- Pounds to Ounceslbs to oz converter
- Carats to Gramsct to g converter
- Troy Ounces to Gramsozt to g converter
- GB to MBGB to MB converter
- MB to GBMB to GB converter
- TB to GBTB to GB converter
- Mbps to MB/sMbps to MB/s converter
- MB/s to MbpsMB/s to Mbps converter
- Gbps to MbpsGbps to Mbps converter
- KB to MBKB to MB converter
- Kbps to MbpsKbps to Mbps converter
- GiB to GBGiB to GB converter
- Bits to Bytesbit to byte converter
- MB to KBMB to KB converter
- GB to TBGB to TB converter
- Liters to GallonsL to gal converter
- Gallons to Litersgal to L converter
- mL to Fluid OuncesmL to fl oz converter
- Cups to mLcup to mL converter
- Pints to Literspt to L converter
- Quarts to Litersqt to L converter
- Tablespoons to mLtbsp to mL converter
- Teaspoons to mLtsp to mL converter
- Liters to CupsL to cup converter
- Cubic Meters to Litersm³ to L converter
- km/h to mphkm/h to mph converter
- mph to km/hmph to km/h converter
- km/h to m/skm/h to m/s converter
- m/s to km/hm/s to km/h converter
- Knots to km/hkn to km/h converter
- Knots to mphkn to mph converter
- Square Meters to Square Feetm² to ft² converter
- Square Feet to Square Metersft² to m² converter
- Acres to Hectaresac to ha converter
- Hectares to Acresha to ac converter
- Square Meters to Acresm² to ac converter
- Square km to Square Mileskm² to mi² converter
- Cups to Gramscup to g converter
- Grams to Cupsg to cup converter
- Fluid Ounces to mLfl oz to mL converter
- Tablespoons to Teaspoonstbsp to tsp converter
- mL to CupsmL to cup converter
- MPG to L/100kmMPG to L/100km converter
- L/100km to MPGL/100km to MPG converter
- km/L to MPGkm/L to MPG converter
- Watts to KilowattsW to kW converter
- Horsepower to Wattshp to W converter
- kWh to JouleskWh to J converter
- Joules to CaloriesJ to cal converter
- Calories to Joulescal to J converter
- BTU to JoulesBTU to J converter
- Watts to HorsepowerW to hp converter
- kcal to kJkcal to kJ converter
- Kilojoules to KilocaloriesConvert kilojoules to kilocalories.
- PSI to BarPSI to bar converter
- Bar to PSIbar to PSI converter
- atm to PSIatm to PSI converter
- Pascals to atmPa to atm converter
- mmHg to atmmmHg to atm converter
- Hours to Minuteshr to min converter
- Minutes to Hoursmin to hr converter
- Days to Hoursday to hr converter
- Seconds to Minutessec to min converter
- Weeks to Dayswk to day converter
- px to rempx to rem converter
- px to empx to em converter
- px to ptpx to pt converter
- Amps to MilliampsA to mA converter
- kWh to WhkWh to Wh converter
- Volts to MillivoltsV to mV converter
- Hz to kHzHz to kHz converter
- MHz to GHzMHz to GHz converter
- Degrees to Radiansdeg to rad converter
- Radians to Degreesrad to deg converter
- Newtons to Pound-forceN to lbf converter
- Newton-meters to Foot-poundsN·m to ft·lb converter