Free online science and maths tools

Draws Lissajous curves from two sine waves with adjustable frequency and phase.

Estimates pi by randomly scattering points in a square and counting those in a circle.

Simulates a body orbiting a mass with adjustable starting speed and distance.

Shows the frequency spectrum of sound from your microphone or a test tone.

Displays audio from the microphone as an oscilloscope trace.

Maps a wavelength of light to its visible colour with a slider.

Estimates the PCB trace width needed to carry a given current within a temperature rise.

Calculates the speed of air moving through a duct for HVAC design.

Interactive article with flow simulations that explain how wings generate lift.

Lists all factors and factor pairs of an integer.

Metric and imperial unit converters with conversion tables.

Plots magnitude and phase of a transfer function with presets for common filters.

Assemble a DNA strand base pair by base pair in an interactive.

Scientific calculator in Portuguese with trig and log functions.

Portuguese matrix calculator for common operations.

Zoom from a coffee bean down to atoms to compare the size of cells and molecules.

Runs chi-square tests of independence or fit and returns the p-value.

Computes chi-square statistics and P values for contingency tables.

Browser schematic editor with a simulator for DC, AC and transient analysis.

Map that shows areas at risk of flooding from sea level rise.

Plots global temperature, sea ice and weather model data from reanalysis datasets.

Daily maps and charts of world temperature and weather model output.

Interactive essay with 3D plots showing how colour spaces represent what we see.

Computes confidence intervals for means and proportions.