The chronological age of your brain may be older or younger than your organ's biological age. Factors such as genetics (some people just age faster than others), lifestyle (smoking, drinking, obesity, chronic stress and inactivity--both mental and physical--accelerate aging in your brain, while physical and mental exercise, frequent social interactions with friends and family and healthy eating actually make your brain younger).
The test below, a version of the Trail Making Test (TMT), gives a rough indication of your brain's actual age. The test is simple: click on the age group into which you fall, then successively click on the green buttons in numbered order. After each click (except on green circle "1") you will see a "trail" between the number you just clicked and the previous number. Click on the numbered circles as fast as you can until you've clicked all 25. If you don’t see a line trail after each click, you missed the button and must click it again before proceeding. You will hear a "click" when click Green Button 1 to let you know the test has started properly.
When you've finished, your time (in seconds) will display, along with running averages for each age category, based upon the responses of all of the other people who have taken this test. Your score will move the average for your age group up or down slightly, because your score will be added to all previous scores for your age category before the average is recalculated and displayed.
Completion times on the TMT strongly correlate with age. For example, on the paper and pencil version of the TMT (Version A), people 18-25 years old average about 20 seconds, while healthy individuals 85-90 years old typically take over 50 seconds to complete the test. The TMT provides a fairly good measure of the brain's "true" age because the primary effect of aging on the brain is to slow down its cognitive processes (probably due to decreases in the amount of myelin--also known as white matter--insulating and speeding up conduction in nerve fibers).
You may take the test as many times as you like to see how much you can improve your scores. It turns out that the simple act of taking the trails test over and over actually slows the aging process in your brain!
For those of you who are familiar with the TMT, the interactive version of this test takes most people longer to complete than the paper and pencil version because guiding a mouse and clicking on numbered circles consumes more time than simply moving a pencil across paper.
Be sure that you can see all 25 numbers before starting; if you can't scroll down until you can see all the numbers AND the hyperlink at the bottom of the page that takes you back to psychologytoday.com. If you have a Firefox brower, you may have to click Green Button 1 to start (Firefox does not like the APP for some reason). Finally, the APP does not work well on mobile devices because of the difficulty of rapidly maniupulating small touch surfaces.
Good luck!