Uploaded June 2026 | Updated September 2026, 1 week ago
start.brainathlete.com/bbm
Ron White 2 time USA Memory Champion best memory program at link above!
Most people pull out their phone every time they need to convert miles to kilometers or kilometers to miles. After this video you won't need to.
There are two dead-simple mental math tricks that get you within a hair of the exact answer — no calculator, no Google, no app.
Miles to Kilometers:
Double the miles, then subtract 20% of that number. That's it.
Take 10 miles. Double it — you get 20. Twenty percent of 20 is 4.
Subtract 4 from 20 and you get 16 kilometers. The actual answer is 16.09. Close enough to be useful anywhere in the world.
Kilometers to Miles:
Divide the kilometers in half, then add 20% of that number back.
Take 50 kilometers. Divide it in half — you get 25. Twenty percent of 25 is 5. Add 5 back to 25 and you get 30 miles. The actual answer is 31.07. Fast, accurate, and done entirely in your head.
These tricks work whether you're traveling internationally, following a running route, or just trying to understand a speed limit sign in a foreign country. Once you learn them you'll never need to Google a conversion again.
start.brainathlete.com/bbm
Ron White 2 time USA Memory Champion best memory program at link above!
Most people pull out their phone every time they need to convert miles to kilometers or kilometers to miles. After this video you won't need to.
There are two dead-simple mental math tricks that get you within a hair of the exact answer — no calculator, no Google, no app.
Miles to Kilometers:
Double the miles, then subtract 20% of that number. That's it.
Take 10 miles. Double it — you get 20. Twenty percent of 20 is 4.
Subtract 4 from 20 and you get 16 kilometers. The actual answer is 16.09. Close enough to be useful anywhere in the world.
Kilometers to Miles:
Divide the kilometers in half, then add 20% of that number back.
Take 50 kilometers. Divide it in half — you get 25. Twenty percent of 25 is 5. Add 5 back to 25 and you get 30 miles. The actual answer is 31.07. Fast, accurate, and done entirely in your head.
These tricks work whether you're traveling internationally, following a running route, or just trying to understand a speed limit sign in a foreign country. Once you learn them you'll never need to Google a conversion again.
