Order-of-Magnitude Quiz

Practice your order-of-magnitude knowledge

Select which question sets you want to include:


Give each answer as the order-of-magnitude (100 ~ E2, 1 million ~ E6, 0.01 ~ E-2, 4 ~ E1). So for example, skyscrapers can be 100 m to 1000 m tall, so you could answer E2 or E3:

To submit your answer, press the 'Answer' button, or press Enter on your keyboard.

Once you're fairly familiar with the questions, it will be faster to do the quiz without 'Show answer after each question' checked.

Comparison Quiz Instructions

Each question in the comparison quiz will give two items. Give the order of magnitude of the ratio between their values. For example, if the prompt gives 'Earth Diameter' (which is E7 m) and 'Inch' (which is E-2 m), then the ratio is E9. The ratio is always larger/smaller, so the order-of-magnitude will never be negative.


This quiz page can be saved and used offline. Just download and select 'complete' web page as the file type

For phones, you may be able to save offline by selecting 'Add to home screen'


  • Do the 'Basic Distance / Size' set
  • Do each 'Basic' question set alone
  • Do all the 'Basic' question sets together
  • Do each 'Basic' set along with any others in the same category
  • Do all sets together
  • Download the Anki deck to get them all in your long-term memory

Once you've learned the values to the point you're comfortable running through all the question sets, you can commit them to more long-term memory using this Anki deck:


oom-quiz.apkg