The homework and exam toolkit: calculate your GPA and the grade you need on the final, work through geometry area and volume, solve equations, run statistics like standard deviation and confidence intervals, and check chemistry and physics formulas. Everything is free with no account, so you can get the answer and the method without hitting a paywall or an ad wall. All 118 tools below are free, run in your browser, and need no sign-up.
Free Ohm's law calculator. Enter any two of voltage, current, resistance or power and instantly solve for the other two using V=IR and P=VI.
Free resistor color code calculator. Pick the bands on a 4, 5 or 6 band resistor and read the resistance value, tolerance and temperature coefficient.
Free scientific notation converter. Convert any decimal number to scientific and E notation, or expand scientific notation back to a plain decimal.
Free significant figures counter and rounder. Count the sig figs in any number and round it to a chosen number of significant figures instantly.
Free pH calculator. Convert between hydrogen ion concentration and pH, find pOH and hydroxide concentration, and classify a solution as acid or base.
Free molarity calculator. Solve for molar concentration, moles of solute, or solution volume using M equals moles divided by liters. Enter any two.
Free molar mass calculator. Type a chemical formula like H2O or Ca(OH)2 and get its molar mass in grams per mole with a per element breakdown.
Free density calculator. Solve for density, mass, or volume using density equals mass over volume. Enter any two values and get the third instantly.
Free force calculator using Newton's second law. Solve for force, mass, or acceleration with F equals m times a. Enter any two and get the third.
Free kinetic energy calculator. Compute kinetic energy from mass and velocity, or solve for mass or speed, using KE equals one half m v squared.
Free gravitational potential energy calculator. Compute PE from mass, gravity and height using PE equals m g h, or solve for any missing value.
Free wavelength to frequency converter. Convert between wavelength and frequency for light or any wave using c equals lambda times f. Set the wave speed.
Free voltage divider calculator. Enter the input voltage and two resistor values to find the output voltage using Vout equals Vin times R2 over R1 plus R2.
Free capacitor code calculator. Enter a 3 digit ceramic capacitor code like 104 and get the capacitance in picofarads, nanofarads and microfarads.
Free weight on planets calculator. Enter your weight on Earth to see what you would weigh on the Moon, Mars, Jupiter and every planet in the solar system.
Free ideal gas law calculator. Solve PV equals nRT for pressure, volume, moles or temperature. Enter any three values using SI units and get the fourth.
Free torque calculator. Compute torque from force, lever arm length and angle using tau equals force times radius times the sine of the angle.
Free percent error calculator. Compare a measured value against the true value and get the absolute error and percent error for lab reports instantly.
Free decibel calculator. Convert a power or amplitude ratio to decibels and back, using 10 log for power and 20 log for voltage or amplitude ratios.
Free speed distance time calculator. Solve for speed, distance or time using speed equals distance over time. Enter any two values and get the third.
Free acceleration calculator. Find acceleration from the change in velocity over time using a equals delta v over t, or solve for velocity or time.
Free projectile motion calculator. Enter launch speed and angle to find range, maximum height and flight time for a projectile on level ground.
Free half-life calculator. Find the remaining amount of a decaying substance after a given time, or work out its half-life from an amount and elapsed time.
Free specific heat calculator. Solve the heat equation Q equals m c delta T for heat energy, mass, specific heat or temperature change. Enter any three.
Free prime number checker. Enter any whole number and instantly see whether it is prime or composite, with its smallest factor when it is not.
Free prime factorization calculator. Break any whole number into its prime factors and see the result in expanded and exponent form instantly.
Free factorial calculator. Compute n factorial for any non-negative integer, with exact big-integer results and no rounding for large inputs.
Free Fibonacci sequence generator. Produce the first N Fibonacci numbers with exact big-integer values, plus the nth term and running sum.
Free percentage increase and decrease calculator. Find the percent change between two numbers and the new value after applying a percentage.
Free ratio simplifier. Reduce any ratio to its simplest whole-number form and see the decimal equivalent, using the greatest common divisor.
Free mean, median, mode and range calculator. Paste a list of numbers and get all four measures of center and spread instantly, with the count and sum.
Free number to words converter. Spell any whole number in plain English, from zero up into the trillions, for checks, contracts and homework.
Free base converter for any radix from 2 to 36. Convert a number between binary, octal, decimal, hex and any custom base with one entry.
Free modulo calculator. Find the remainder of a division, plus the quotient and the true mathematical modulo, for any two numbers instantly.
Free exponent calculator. Raise any base to any power, including negative and fractional exponents, and see the exact or precise decimal result.
Free logarithm calculator. Compute the log of any positive number in any base, including natural log and log base 10, with the exponent check shown.
Free permutation and combination calculator. Compute nPr and nCr for any n and r using exact big-integer math, with the factorial formulas shown.
Free probability calculator. Find the probability of single and combined events, including AND, OR, and NOT, as a fraction, decimal and percentage.
Free fraction to decimal converter. Turn any fraction into its decimal value and percentage, and see repeating digits marked clearly.
Free decimal to fraction converter. Turn any decimal into its exact simplified fraction, including repeating decimals, plus a mixed number form.
Free proportion solver. Cross multiply to solve for the missing value in a proportion a over b equals c over x, with the work shown.
Free slope calculator. Enter two points and get the slope, the line equation, the angle in degrees, and the y-intercept instantly.
Free distance between two points calculator. Use the distance formula to find the straight-line length between two coordinates, with the steps shown.
Free midpoint calculator. Find the exact midpoint between two coordinates using the midpoint formula, averaging the x and y values.
Free scientific notation converter. Switch between standard decimal numbers and scientific notation both ways, with the E-notation form shown too.
Free rounding calculator. Round any number to a set number of decimal places, significant figures, or the nearest ten, hundred or thousand.
Free LCM of a list calculator. Find the least common multiple of many numbers at once, using exact big-integer math so large results stay precise.
Free greatest common factor calculator. Find the GCF of many numbers at once using the Euclidean algorithm, exact for very large values.
Free arithmetic series calculator. Sum an arithmetic sequence from its first term, common difference and length, or find the nth term instantly.
Free triangle area calculator. Find the area of any triangle from its three sides using Heron formula, or from a base and height, instantly.
Free weighted GPA calculator for high school. Add course grades, credit hours and class level (regular, honors, AP or IB) to get your weighted GPA.
Free semester GPA calculator. Enter each class letter grade and credit hours for one term to get your semester grade point average on a 4.0 scale.
Free college GPA calculator with credit hours. Enter each course grade and credits to compute your college GPA on the standard 4.0 university scale.
Free high school GPA calculator on the 4.0 unweighted scale. Enter your class grades to instantly find your high school grade point average.
Free weighted grade calculator by category. Enter your scores and the weight of each category to compute your overall course grade and letter.
Find the score you need on your final exam to hit your target grade. Enter your current grade, the target and the final worth to get the answer.
Convert correct answers out of total questions into a percentage and letter grade. Free instant test and quiz score calculator for students.
Convert a percentage score into a letter grade and 4.0 grade point instantly. Free percentage to letter grade calculator with a full scale table.
Check if your score passes and how far you are from the passing mark. Free pass or fail calculator with a custom passing threshold for any test.
Convert your class rank and class size into a percentile and top percent. Free class rank percentile calculator for high school and college.
Work out how many more points you need to reach your target grade. Free points needed calculator using points earned out of total points possible.
Apply a class curve to a raw score. Free grade curve calculator supporting flat point boost, square root curve and top score scaling methods.
Calculate your attendance percentage from classes attended and total held, and see how many you can still miss to stay above a required minimum.
Estimate weekly study hours and total workload from your enrolled credit hours using the standard two hours of study per credit guideline.
Estimate how long a reading assignment will take from page or word count, difficulty and your reading speed. Free study planner for students.
Split your available study hours across subjects by priority weight. Free study time planner that shows how many hours to give each subject per week.
Count down to your exam date and see days, weeks and study days left, plus suggested daily study time to cover your material in time.
See how a future assignment score changes your overall grade before you submit it. Free grade impact planner using current grade and item weight.
Generate spaced repetition review dates for a flashcard using a Leitner style schedule. Free spaced repetition interval calculator for studying.
Average several grades where each has a different weight. Free weighted average grade calculator for combining tests, projects and homework fairly.
Add up your IB subject grades plus the extended essay and theory of knowledge bonus to get your total out of 45 and check if you pass the diploma.
Convert a percentage grade into a 4.0 scale GPA value and letter grade. Free percentage to GPA converter for transcripts and study abroad applications.
Free circle area calculator. Enter a radius or diameter to get the area of a circle instantly using pi times r squared, right in your browser.
Free circle circumference calculator. Enter a radius or diameter to get the distance around a circle using 2 pi r, instantly in your browser.
Free rectangle area calculator. Enter length and width to get the area and perimeter of a rectangle instantly, all in your browser.
Free square area calculator. Enter the side length to get the area, perimeter and diagonal of a square instantly in your browser.
Free trapezoid area calculator. Enter the two parallel sides and the height to get the area of a trapezoid instantly in your browser.
Free parallelogram area calculator. Enter the base and height to get the area of a parallelogram instantly using base times height in your browser.
Free rhombus area calculator. Enter the two diagonals to get the area of a rhombus instantly using half the product of the diagonals in your browser.
Free ellipse area calculator. Enter the semi major and semi minor axes to get the area of an ellipse instantly using pi times a times b.
Free regular polygon area calculator. Enter the number of sides and side length to get area and perimeter of any regular polygon in your browser.
Free regular hexagon calculator. Enter the side length to get area, perimeter, and both the long and short diagonals of a hexagon instantly.
Free circle sector area calculator. Enter the radius and central angle in degrees to get the area of a pie slice sector instantly in your browser.
Free arc length calculator. Enter the radius and central angle to get the arc length of a circle using r times theta, instantly in your browser.
Free Heron formula calculator. Enter the three side lengths of a triangle to get its area using Heron formula instantly in your browser.
Free triangle perimeter calculator. Enter the three side lengths to get the perimeter and semi perimeter of a triangle instantly in your browser.
Free Pythagorean theorem calculator. Enter two sides of a right triangle to find the hypotenuse or a missing leg using a squared plus b squared.
Free right triangle calculator. Enter the two legs to get the hypotenuse, area, perimeter and both acute angles of a right triangle instantly.
Free cube volume calculator. Enter the edge length to get the volume, surface area and diagonal of a cube instantly using edge cubed in your browser.
Free rectangular prism volume calculator. Enter length, width and height to get the volume and surface area of a box instantly in your browser.
Free sphere volume calculator. Enter the radius to get the volume and surface area of a sphere instantly using four thirds pi r cubed in your browser.
Free cylinder volume calculator. Enter the radius and height to get the volume and surface area of a cylinder instantly using pi r squared h.
Free cone volume calculator. Enter the radius and height to get the volume, slant height and surface area of a cone instantly in your browser.
Free square pyramid volume calculator. Enter the base edge and height to get the volume, slant height and surface area of a pyramid in your browser.
Free box surface area calculator. Enter length, width and height to get the total surface area of a rectangular box instantly in your browser.
Free 3D distance calculator. Enter two points in x y z space to get the straight line distance between them instantly using the 3D distance formula.
Free confidence interval calculator. Enter a sample mean, standard deviation and size to get the lower and upper bounds at 90, 95 or 99 percent.
Free sample size calculator for surveys. Enter your confidence level, margin of error and population to find how many responses you need.
Free margin of error calculator. Enter a sample proportion, sample size and confidence level to find the plus or minus error of your poll.
Free z-score calculator. Enter a value, mean and standard deviation to find how many standard deviations it sits from the average, with percentile.
Free p-value calculator from a z-score. Enter a z value and choose a one or two tailed test to get the exact p-value for hypothesis testing.
Free percentile calculator. Paste a data set and pick a percentile from 0 to 100 to find the value at that position using linear interpolation.
Free percentile rank calculator. Paste a data set and a value to find what percent of the numbers fall at or below it, from 0 to 100.
Free Pearson correlation coefficient calculator. Paste paired x and y data to find r, the strength and direction of a linear relationship.
Free covariance calculator. Paste paired x and y data to find the sample and population covariance measuring how two variables vary together.
Free standard error calculator. Paste a data set or enter a standard deviation and sample size to find the standard error of the mean.
Free variance calculator. Paste a data set to find the sample and population variance, plus standard deviation, mean and sum of squares.
Free coefficient of variation calculator. Paste a data set to find the CV, the standard deviation as a percent of the mean, for comparing spread.
Free five number summary calculator. Paste a data set to get the minimum, first quartile, median, third quartile and maximum at a glance.
Free interquartile range calculator. Paste a data set to find the IQR along with the first and third quartiles and the median in one step.
Free outlier detector using the 1.5 IQR rule. Paste a data set to find outliers, the fence boundaries and the clean values that remain.
Free geometric mean calculator. Paste positive numbers to find their geometric mean, the right average for growth rates, ratios and returns.
Free harmonic mean calculator. Paste positive numbers to find their harmonic mean, the correct average for rates like speed and price ratios.
Free weighted mean calculator. Enter values and their weights to find the weighted average, where more important items count for more.
Free normal distribution calculator. Enter a value, mean and standard deviation to find the probability density and cumulative probability.
Free binomial probability calculator. Enter trials, successes and success probability to find exact, at most and at least binomial probabilities.
Free Poisson probability calculator. Enter an average rate and a count to find exact, at most and at least Poisson probabilities for rare events.
Free relative frequency calculator. Paste category counts to build a frequency table with relative and cumulative frequencies as percentages.
Yes. Every tool in this toolkit is completely free, with no sign-up and no usage limits.
Yes. They run in any modern web browser on phone, tablet or desktop, with nothing to install.
Yes. These tools run entirely in your browser, so nothing you enter is uploaded to a server.