🧮Calculators

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Egg Boiling Time Chart (Soft, Medium, Hard)

Pick the yolk you want and get the time in boiling water: 4 minutes soft-boiled, 7 minutes medium, 10 minutes hard-boiled. Start counting at the boil.

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Barbecue Meat Calculator

Calculate how much meat to buy for your barbecue from the number of adults and children. Get the right amount of meat, drinks and sides without waste.

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Party Drinks Calculator

Find out how many drinks to buy for your party based on the number and profile of guests. Plan beer, soda, water and cocktails without waste.

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Recipe Yield & Scaler

Calculate how many servings a recipe yields and scale the ingredients up or down. Adapt any dish to the number of guests without messing up the amounts.

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Refrigerator Thawing Time

Estimates how many hours a cut of meat needs to thaw in the fridge from its weight in kilograms, at the safe rule of about 24 hours per 2 kg.

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Note Duration Calculator (BPM to ms)

Turns a tempo in BPM into note lengths in milliseconds, from whole to sixteenth notes, using 60000 / BPM. Handy for delay and reverb times.

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Musical Interval Calculator (Semitones to Name)

Converts a semitone count into the interval name, from unison and minor 2nd through the tritone to the major 7th, wrapping within one octave.

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1RM Lombardi Calculator

Estimate your one-rep max (1RM) with the Lombardi formula from the weight lifted and reps performed. Plan training loads without attempting a true max.

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Tanaka Formula Max Heart Rate Calculator

Enter your age and get maximum heart rate in bpm from 208 - 0.7 x age, the 2001 revision that fits adults better than the old 220 minus age rule.

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YMCA Body Fat from Waist Circumference

Estimates male body fat percentage from body weight and waist measurement with the simplified YMCA formula, so no skinfold caliper is required.

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FFMI Calculator

Calculate your FFMI (fat-free mass index), which measures muscle mass relative to height. A useful alternative to BMI for people who lift weights.

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Light-Years to Travel Time

Turns a distance in light-years and a cruise speed given as a percentage of the speed of light into the trip duration in years, as clocked from Earth.

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BMI Calculator (Adults)

Calculate your BMI (Body Mass Index) from weight and height and see the WHO classification, from underweight to obese. Fast and no sign-up needed.

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Espresso Extraction Time

Find the ideal extraction time for your espresso (around 25 to 30 seconds for 30 ml). Dial in your coffee and adjust the grind for a perfect shot.

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Prime Factorization Calculator

Splits a whole number of 2 or more into its prime powers by trial division: type 360 and read back 2^3 · 3^2 · 5, the unique decomposition.

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GCD Calculator (Euclidean Algorithm)

Returns the greatest common divisor of two integers through repeated remainder division, the Euclidean algorithm. Signs are ignored and decimals truncated.

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LCM Calculator (Two Numbers)

Calculate the least common multiple (LCM) of two integers. See the steps using the relation LCM = |a·b| / GCD. Handy for fractions and school problems.

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Modular Inverse Calculator

Calculate the modular inverse a⁻¹ mod m with the extended Euclidean algorithm. The inverse exists when a and m are coprime. Key in cryptography and number theory.

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Modular Exponentiation Calculator

Calculate modular exponentiation (b to the power e, modulo m) fast with the square-and-multiply method. Essential in RSA cryptography and number theory.

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Quadratic Roots and Discriminant Calculator

Enter a, b and c to get b² − 4ac and the two solutions of ax² + bx + c = 0, real when that value is zero or positive and complex when it is negative.

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Cubic Equation Solver (Cardano's Formula)

Enter p and q of the depressed cubic t³ + pt + q = 0 to get the discriminant q²/4 + p³/27 and one real root, or all three real roots when it is negative.

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2x2 Matrix Determinant and Inverse

Calculate the determinant and inverse of a 2x2 matrix from its four entries. See the step-by-step and the exact result in fractions or decimals.

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3x3 Matrix Determinant Calculator

Calculate the determinant of a 3x3 matrix using Sarrus' rule from its nine entries. See the worked-out calculation and the result instantly.

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3D Cross Product of Two Vectors

Type the x, y and z components of two vectors and get a × b, the vector perpendicular to both, whose length equals the area of the parallelogram they span.

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3D Dot Product Calculator

Calculate the dot product (scalar product) of two 3D vectors from their x, y and z coordinates. Useful in physics, computer graphics and vector geometry.

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3D Vector Magnitude Calculator

Calculate the magnitude (length or norm) of a 3D vector from its x, y and z coordinates. Useful in physics, engineering and computer graphics.

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Complex Number Addition

Enter the real and imaginary parts of z1 and z2 to add them: (a + bi) + (c + di) = (a+c) + (b+d)i, with the result returned in a + bi form.

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Complex Number Multiplication

Enter the real and imaginary parts of z1 and z2 to get the product (ac − bd) + (ad + bc)i, the expansion that applies i squared = -1.

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Complex Number Modulus and Phase (Polar Form)

Enter the real and imaginary parts of z to get the magnitude sqrt(a^2 + b^2) and the argument atan2(b, a), reported in radians and in degrees.

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Horner Method Polynomial Evaluator

Enter the coefficients from the highest degree down to the constant, comma separated, plus a value of x, to get p(x) in n multiplications and n additions.

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Pascal Triangle Row Calculator

Generate any row of Pascal triangle by entering the row number. See the binomial coefficients instantly — useful for combinatorics, algebra and math study.

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Nth Fibonacci Number Calculator

Enter an index n and get F(n) from the recurrence F(n) = F(n-1) + F(n-2), starting at F(0) = 0 and F(1) = 1, as an exact integer up to n = 78.

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Large Factorial Calculator

Calculate the factorial of large numbers (n!) with arbitrary precision using BigInt, with no lost digits. Ideal for combinatorics and probability.

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Binomial Coefficient C(n,k) Calculator

Calculate the binomial coefficient C(n,k): the number of ways to choose k items from n, with no overflow. Key in probability and combinatorics.

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Permutations P(n,k) Calculator

Calculate permutations P(n,k), the number of ordered arrangements of k items chosen from n. Useful for probability, draws and combinatorics.

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Combinations Calculator C(n,k)

Calculate combinations C(n,k): how many ways you can choose k items from a set of n, where order does not matter. The basis of combinatorics.

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GCD of Multiple Numbers Calculator

Calculate the GCD (greatest common divisor) of a list of integers all at once. Enter the values separated by commas and see the result instantly.

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Prime Number Checker: Trial Division Test

Tells you whether a whole number is prime by dividing up to its square root, naming the first divisor when it is not. Practical up to about 10^12.

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Euler's Totient Function φ(n)

Enter an integer n and get the count of integers from 1 to n that are coprime with n, computed by prime factorization: n = 36 returns 12.

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Partial Fraction Decomposition of 1/((ax+b)(cx+d))

Enter the coefficients a, b, c and d to split the rational function into A/(ax+b) + B/(cx+d) by Heaviside cover-up. Needs ad - bc not zero.

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One-Sample t-Test Calculator

Calculate the t-statistic for a one-sample t-test from the mean, standard deviation and sample size. Compare your sample mean against a reference value.

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Chi-Square Goodness-of-Fit Calculator

Calculate the chi-square (χ²) goodness-of-fit statistic from observed and expected frequencies. Test whether your data follows the expected distribution.

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Pearson Correlation Calculator

Calculate the Pearson correlation coefficient (r) between two data sets and measure the strength of the linear relationship, from -1 to +1.

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Linear Regression Slope and Intercept (Least Squares)

Paste two comma-separated lists of paired X and Y values and get the ordinary least squares coefficients a and b of the line y = ax + b.

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Normal CDF Φ(z) Approximation

Enter a z-score to get Φ(z), the cumulative probability of the standard normal N(0,1), via the Abramowitz-Stegun error function approximation.

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Normal Distribution PDF Calculator

Calculate the probability density of the normal (Gaussian) distribution at a point, from the mean and standard deviation. Key in statistics and data science.

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Standard Error of the Mean Calculator

Calculate the standard error of the mean (SEM) from the standard deviation and sample size. A key metric in statistics, research and confidence intervals.

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Confidence Interval for the Mean (z)

Enter the sample average x̄, a known population σ and the size n to get x̄ ± z·σ/√n at 90, 95 or 99 percent, where z is 1.645, 1.96 or 2.576.

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One-Tailed Z-Test p-Value

Converts an observed z statistic into the right-tail p-value, 1 − Φ(z), the number you compare against an alpha such as 0.05 in a one-sided test.

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Descriptive Statistics Calculator

Calculate descriptive statistics for a list of numbers: mean, median, mode, variance and standard deviation. Paste your data and see every result.

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Quartiles & IQR Calculator

Calculate the quartiles (Q1, Q2/median, Q3) and the interquartile range (IQR) of a list of numbers. Spot the spread and possible outliers in your data.

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MAD (Median Absolute Deviation)

Takes a comma-separated list of numbers and returns the median absolute deviation, median of |xi − median(x)|, a spread measure that resists outliers.

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RMSE Between Two Lists

Paste observed and predicted values as comma-separated lists of equal length and get the root mean squared error, in the same unit as the target variable.

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Range, Variance and Standard Deviation

Paste a comma-separated list of 2 or more numbers to get max minus min, the sample variance s² with the Bessel n-1 divisor, and the sample s.

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Geometric Mean Calculator

Calculate the geometric mean of a list of positive numbers, ideal for growth rates, returns and indexes. Enter the values and see the result instantly.

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Harmonic Mean Calculator

Calculate the harmonic mean of a list of numbers, best suited for averaging rates, speeds and ratios. Enter the values and get the result instantly.

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Percentile Rank Calculator

Paste a comma-separated data set and one value to get 100 * (L + 0.5E) / n: the share of points below it, with every tie counted as half a point.

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Dice Sum Probability Calculator

Enter how many six-sided dice and a target total to get P(sum = s) by convolution, plus the raw count over 6^n. Two dice landing on 7 give 6/36.

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Probability of a Run of Heads

Work out the chance of getting at least k heads in a row in n coin tosses, counted exactly by dynamic programming rather than simulated.

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Lottery Odds (6/60)

Find out the real odds of winning a 6/60 lottery like the Brazilian Mega-Sena. See how unlikely the jackpot truly is, compared with everyday events.