Tools

Everyday Tools, Calculations & Conversions

Age & Date Calculator

Calculate age, Gregorian and Japanese era dates, zodiac signs, monthly birthstones and flowers, periods, and date offsets.

TOOL 02

Percentage Calculator

Choose from ten calculations including percentage amounts, changes, targets, tax, profit margin and repeated changes.

TOOL 03

Unit Converter

Convert length, area, mass, temperature, pressure, and more, or calculate water vapour and dew point.

TOOL 04

Radix Converter

Convert bases and two's-complement integers, then inspect IEEE 754 half/single/double precision, byte order and fixed-point Q formats.

TOOL 18 / WEB UTILITY

QR Code Reader

Read QR codes locally in your browser using a Mac camera, image file, drag and drop, or a pasted screenshot.

Finance & Life Planning

TOOL 05 / FINANCE

Loan Calculator

Calculate a repayment plan or borrowing capacity, and compare the interest, term and payment effects of prepayment.

TOOL 06 / FINANCE

Savings Calculator

Project savings or targets, compare up to three rates and show future balances in today's money after inflation.

Data Analysis

TOOL 07 / DATA ANALYSIS

Polynomial Regression & Graph

Select two columns from up to five data series and 20 rows, then calculate a degree 1–5 polynomial fit and graph.

TOOL 08 / DATA ANALYSIS

Statistics Calculator

Paste numbers to calculate mean, median, variance, standard deviation, quartiles and coefficient of variation, with a histogram.

TOOL 09 / DATA ANALYSIS

Function Plotter

Plot up to two functions together and inspect their intersections and coordinates within the displayed range.

Control, Numerical Analysis & Circuits

TOOL 10 / CONTROL DEMO

PID Playground

Adjust Kp, Ki and Kd to explore a first-order response, control output, rise time and overshoot.

TOOL 11 / NUMERICAL DEMO

Numerical Integration Playground

Explore five numerical integration rules through approximations, reference values, errors and graphs of their area shapes.

TOOL 12 / NUMERICAL DEMO

Differential Equation Visualizer

Compare solutions and errors from five first-order ODE methods and inspect the equation used by each method.

TOOL 13 / NUMERICAL DEMO

Nonlinear Solver Visualizer

Enter or select nonlinear systems with up to ten variables and visualise Newton or pseudo-arclength Homotopy, choosing either an exact stop at λ=1 or continued tracking.

TOOL 14

Electrical Circuit Calculator

From basic DC calculations to AC impedance, RLC resonance, dB and op-amps, including RLC frequency-response charts.

Kendo & Tournaments

TOOL 17 / KENDO