How many grains of sand are there in the world?

According to the University of Hawaii's answer:

There are seven quintillion five quadrillion grains of sand on all the beaches of the world. That's a 75 with 17 zeros following!

"75 with 17 zeros following" (7.5x10^18) is seven quintillion, five hundred quadrillion. But what's an extra 495 quadrillion with so many variables in the equation?

Consider more possibilities...

With oceans rising and the deserts expanding, the question of grains of sand on the beach is kind of arbitrary. I think we would do better to ponder a more global picture: an estimate of all "sand" particles on the entire earth's surface, (including that which is covered by salty, briny, or fresh seas and rivers).

Of course "sand" varies by composition, but is defined by size of particle. Tough questions then arise regarding the unexplored ocean floor, which includes a lot of silt (the same composition, but different size per particle than sand). Perhaps we could correct for that based on volume of silt, (or gravel, for that matter), per grain of sand under the sea.

With massive erosion occurring due to water runoff and flooding caused by widespread deforestation, the intractability of the problem becomes as troublesome as estimating the number of stars in the expanding universe. Isn't that the analogy that captures our imagination, anyway - stars versus grains of sand?

But another answer is:

The exact number is not known.

The exact number can't be known to mere mortals. The number of grains of sand is constantly changing as rock is worn away daily into more sand and tons of sand are melted daily to make glass and other products. Then you come to the dilemma of deciding the point at which sand ground fine enough, when do you start to call it dust.

It is pretty clear that it is pretty hard to tell how many grains of sand there are on the beach. But i think there must be billions or millions of grains of sand all around the world. There must be 1,000, 000, 000, 000, 000, 000, 000, and i know there must be alot of sands all around the world.

This is an un-answerable question due to the fact that the number of grains of sand is constantly changing and we can not keep up with it. But I can tell you that Florida has more grains of sand than Rhode Island and less than the Sahara Desert. Hope I helped. Still counting.

Diameter of a grain of sand = 0.2 mm Volume of a grain of sand = 0.0042 mm^3 Volume of bounding box = 0.008 mm^3 Volume of a 3 minute times = 2 cm^3 = 2000 mm^3 Grains of sand in a 3 min timer = 2,000/0.008 = 250,000 grains Grains of sand in a 1 hour timer = 250,000 x 60 / 3 = 5,000,000

7,008 grains= 1 pound of sand. Answer: The term "sand" can be assigned to wide range of particles. Studies indicate that mid-sized sands weigh 0.67 - 23 mg per grain. This means there are from 1 500 000 to 43 000 grains per kg. A kg is 2.2 lb., so there are potentially 700 000 to 22 000 grains per pound.