All calculators by topic

Perform quick addition, subtraction, multiplication, and division.

Find parts, originals, raw percent values, or percentage change.

Simultaneously get least common multiple and greatest common factor.

Trig, logs, exponentials, and powers with degree/radian toggles.

Operate on rational numbers with automatic simplification.

Solve triangle perimeter, area, and internal angles from three sides.

Roots, discriminant, and root nature for quadratic equations.

Break integers into ordered prime factors.

Computes percent difference between a starting and ending value.

Finds the percentage difference between any two measurements.

Converts between standard numbers and scientific notation.

Computes logarithms in base 10, base e, or any custom base.

Models exponential change with initial value, rate, and time.

Finds approximate roots (real or complex) for higher-degree polynomials.

Solves linear systems using an augmented matrix.

Estimate monthly cost, total interest, and payoff for fixed-rate loans.

Principal & interest plus taxes, insurance, and HOA for home buyers.

Project growth with recurring contributions and compounding frequency.

Model retirement savings with monthly contributions and risk profiles.

Live-style currency conversions using configurable base rates.

Calculates effective annual rate and periodic interest from a nominal rate.

Converts annual pay into hourly, weekly, and monthly equivalents.

Estimates take-home pay using simple US, UK, or Canada tax brackets.

Computes ROI, absolute gain, and compound annual growth (CAGR).

Projects SIP maturity, total contributions, and wealth gained over time.

Estimates crypto trade P&L after exchange fees, gas, and slippage.

Compares straight-line and declining-balance depreciation schedules.

Generates amortization schedules and payment breakdowns.

Adjusts money between years using an average inflation rate.

Adds or removes Goods and Services Tax from any amount.

Finds the equated monthly installment for any fixed-rate loan.

Metric-friendly BMI with category classification.

Feet/inches and pounds for BMI plus weight class insights.

US Navy body-fat estimate with circumference measurements.

Computes Mosteller and Du Bois BSA with quick dosing hints.

BMR, maintenance, cut, and bulk calories via Mifflin-St Jeor.

Total daily energy expenditure from Mifflin-St Jeor BMR and activity multipliers.

Turns daily calories into protein, carb, and fat gram targets using preset or custom ratios.

Shows the deficit, calorie target, and timeline needed to reach a goal weight.

LMP-based due date with trimester milestones.

Daily hydration target from weight, workouts, climate, and life stage adjustments.

Calculates basal metabolic rate from gender, weight, height, and age.

Maps recovery through VO₂ max zones using the Karvonen method.

Compute exact age differences down to the day.

Add/subtract days or measure distance between dates.

Add or subtract HH:MM time spans with wrap-safe output.

Finds local time differences across global cities.

Computes cylinder volume plus lateral and total surface area.

Calculates circle area and circumference from radius or diameter.

Finds the volume and surface area of a sphere from its radius.

Computes hypotenuse, area, perimeter, and angles from the two legs.

Area, perimeter, apothem, and angles for any regular polygon.

Finds mean, median, variance, and standard deviation for a dataset.

Calculates data variability around the mean as variance and standard deviation.

Computes σ, variance, range, and coefficient of variation from any dataset.

Computes event probabilities with percent, fraction, and odds outputs.

Converts any raw score into a standardized z-value, percentile rank, and tail probability.

Finds key measures of central tendency for a dataset.

Finds exact or cumulative probabilities for binomial experiments.

Evaluates z-scores and normal probabilities.

Performs Welch’s two-sample t-test with p-value.

Runs a one-way ANOVA across multiple groups.

Computes the chi-square statistic and p-value for goodness of fit.

Fits a least-squares line, returns slope/intercept, and predicts any Y value.

Finds Pearson r, covariance, and standard deviations for paired samples.

Estimates the responses needed to hit a target margin of error and confidence level.

Two-proportion power analysis for experiments with a target lift, confidence, and power.

Builds a two-sided z-interval around a sample mean.

Universal unit converter covering length, weight, temperature, and more.

Converts decimals to equivalent fractions with simplification.

Converts fractions to decimals quickly for calculations or spreadsheets.

Converts °C, °F, K, and °R with one input.

Converts between kilograms, pounds, and ounces instantly.

Swaps between joules, calories, and watt-hours in one view.

Converts Watts, kilowatts, megawatts, horsepower, and dBm.

Converts bytes among binary KB, MB, GB, and TB (plus bits).

kbps, Mbps, Gbps, and MB/s conversions for throughput planning.

Converts between km/h, mph, and m/s.

Converts between bar, atm, psi, and pascal units.

Converts between square meters, square feet, acres, and hectares.

Converts liters, cubic meters, US gallons, and US pints.

Converts between meters, feet, inches, yards, and miles.

Computes straight-line distance between two or three-dimensional points.

Converts cups, spoons, ounces, grams, liters, and more kitchen-friendly units.

Estimates fuel needed, trip cost, and CO2 for road journeys.

Solves the motion equation when any one variable is missing.

Computes force from mass and acceleration (F = m·a).

Finds mechanical work using force, displacement, and angle.

Finds mechanical power or electrical power from multiple input combinations.

Range, time of flight, and peak height for a launch angle.

Drop time and impact velocity from any height (no drag).

Solves for voltage, current, or resistance in DC circuits.

Decodes resistor band colors into resistance and tolerance.

Equivalent resistance calculator plus branch count at a glance.

Computes capacitance for parallel plate capacitors.

Estimates inductance for air-core and ferrite-core coils.

Splits current through resistors in a parallel branch.

Computes output voltage for resistor dividers with load awareness.

Computes real, reactive, and apparent power with power factor.

Finds τ = R·C plus the time to hit 63%, 95%, and 99% charge levels.

Converts linear power or voltage ratios to decibels and back.

Calculates real, apparent, and reactive power for single- or three-phase systems.

Finds the current-limiting resistor for LEDs on a fixed supply voltage.

Estimates voltage drop across AWG wire sizes and recommends a gauge for your run.

Estimates runtime from battery capacity, load current, and discharge depth.

Computes capacitive and inductive reactance, or LC resonant frequency.

Solves for an unknown resistor at balance or the output voltage of a resistor bridge.

Sizes the series resistor for a Zener diode voltage regulator.

Finds secondary voltage and current from a transformer's turns ratio.

Finds the minimum copper trace width for a target current using IPC-2221.

Converts a peak sine, square, or triangle waveform value to RMS and average.

Finds output frequency and duty cycle for a 555 timer in astable mode.

Evaluates definite integrals and approximates antiderivatives.

Computes first through fourth derivatives at a point.

Evaluates one-sided and two-sided limits numerically.

Computes partial derivatives for functions of two variables.

Performs vector addition and subtraction component-wise.

Finds the scalar product plus the angle between vectors.

Computes the vector cross product in three dimensions.

Computes determinants for square matrices up to 6×6.

Performs matrix multiplication when dimensions are compatible.

Finds eigenvalues and normalized eigenvectors for 2×2 matrices.

Computes nPr, nCr, and factorial values exactly.

Outputs NOAA heat index, Celsius/Fahrenheit feels-like, and safety labels.

Calculates wind chill and frostbite guidance from temperature plus wind speed.

Converts letter grades and credit hours into GPA and quality points.

Tracks assignment scores, current letter grade, and the score needed to hit a target.

Breaks down IPv4 networks into mask, host range, broadcast, and host counts.

Solves PV = nRT for any missing variable with Kelvin temperature.

Convert between pH and hydrogen ion concentration.

Solves for molarity, moles, or volume in mol/L problems.

C₁V₁ = C₂V₂ tool for stock and working solutions.

Applies percentage discounts, quantity, and sales tax to show the true total.

Adds a gratuity and divides the check evenly across the party.

Flat or tiered commission payouts based on total sales.

Calculates the units and revenue needed to cover fixed costs.

Converts markup percentages to margins (and back).

LTV, CAC payback, and contribution per customer from ARPU, churn, and gross margin.

Cash runway calculator with optional monthly burn increases.

Tracks starting MRR, new bookings, expansion, churn, and contraction.

Works backward from your target income to the hourly rate you need to charge.

Shows how a new funding round and option pool affect your ownership percentage.

Calculates simple daily-interest late fees on an overdue invoice.

Finds how long it takes an investment to pay for itself from net cash flow.

Measures the average number of days it takes to collect payment after a credit sale.

Calculates how many times inventory is sold and replaced over a period.

Estimates a severance package from years of service and a per-year week rate.

Blends ROI, ROAS, net profit, and annualized return for any campaign or capital project.

Generates campaign tracking URLs with source, medium, term, and content.

Compares ad revenue to ad spend and finds the break-even ROAS for your margin.

Converts promoter, passive, and detractor counts into your Net Promoter Score.

Breaks marketing spend into cost per lead and cost per acquired customer.