Resistor Colour Code Calculator (4, 5 & 6 Band)

Practice mental math online – addition, subtraction, multiplication tables and division – with 3 levels, a 60-second challenge and instant scores. Great for kids.

Calculate a weighted average (weighted mean) – for grades with different weightages, portfolio returns or survey scores. Add rows of value and weight; see the working.

Find exact and cumulative binomial probabilities P(X = k), P(X ≤ k), P(X ≥ k) with mean, variance and a probability chart.

Calculate the area, circumference, diameter and radius of a circle from any one value – plus arc length and sector area.

Test your geography with a fun flag quiz – guess the country from its flag with 4 options. Choose a continent, 10 or 20 questions, and learn from every answer. Great for students.

Create a professional experience letter / experience certificate for an employee in minutes – with company letterhead, dates, designation, duties and conduct. Edit, print or download as Word.

Calculate the hourly and day rate you should charge as a freelancer to reach your income goal after costs and fees.

Find out how many weeks and days pregnant you are, your trimester, due date and baby’s size this week – from last period, conception date or ultrasound dating.