# If we converted ALL the world's currency into pennies, how many would we have? **URL:** \ **Category:** Factual Questions\ **Created:** [September 2, 2020, 10:56pm UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649 "2020-09-02T22:56:21Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Grrr](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/grrr/32/146_2.png) [@Grrr](https://boards.straightdope.com/u/Grrr)\ **Post date:** [September 2, 2020, 10:56pm UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/1 "2020-09-02T22:56:21Z")
I’m just trying to see if this is in any way comparable to “More stars in the sky then grains of sand on all the beaches in the world.” Also just currious. ---
**Author:** ![Fiendish\_Astronaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fiendish_astronaut/32/3295_2.png) [@Fiendish\_Astronaut](https://boards.straightdope.com/u/Fiendish_Astronaut)\ **Post date:** [September 2, 2020, 11:04pm UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/2 "2020-09-02T23:04:45Z")
This is the sort of GQ question i like. Apparently there is $5 trillion circulating in currency but broadly there is over $80 trillion in the world economy. If you converted all off that into pennies you’d have 80 followed by 15 zeros. That’s 80 quadrillion. ---
**Author:** ![iamthewalrus\_3](https://avatars.discourse-cdn.com/v4/letter/i/258eb7/32.png) [@iamthewalrus\_3](https://boards.straightdope.com/u/iamthewalrus_3)\ **Post date:** [September 3, 2020, 12:35am UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/3 "2020-09-03T00:35:14Z")
Pennies are 3/4 of an inch across and circles have a packing efficiency of 0.9069, so it takes about 3508 of them to cover a square meter. The surface of land area on the earth is 510 trillion square meters, so 80 quadrillion pennies tightly packed would cover about 5% of the surface of the land on earth. If we could evenly distribute them, the measurable amount of good luck in the world would increase dramatically. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [September 3, 2020, 1:03am UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/4 "2020-09-03T01:03:50Z")
The earth would be slightly smaller, after mining all that zinc. ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [September 3, 2020, 1:54am UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/5 "2020-09-03T01:54:25Z")
Follow up question. How high would they stack? Would it reach the moon? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 3, 2020, 2:56am UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/6 "2020-09-03T02:56:35Z")
A penny is 1.52mm thick. 80 quadrillion would be 121.6 quadrillion mm. The distance from the Earth to the Moon is 384.4 billion mm, so your stack of pennies would be 316,337x taller than necessary. In fact, the distance from the Earth to Mars (closest approach) is 54.6 million km, or 54.6 trillion mm, so your little penny tower would be around 2,000x long enough. Distance from Earth to Pluto is around 4.28 billion km, or 4.28 quadrillion mm, so your stack of pennies would reach past it into interstellar space. (If I haven’t made any [miscalculations](https://www.goodreads.com/quotes/5942504-the-mighty-ships-tore-across-the-empty-wastes-of-space) in scale) ---
**Author:** ![snfaulkner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snfaulkner/32/433_2.png) [@snfaulkner](https://boards.straightdope.com/u/snfaulkner)\ **Post date:** [September 3, 2020, 2:59am UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/7 "2020-09-03T02:59:55Z")
How many pennies to collapse into a star? How many to find true love? ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [September 3, 2020, 3:21am UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/8 "2020-09-03T03:21:11Z")
Hmm . . . could it reach Voyager 1 or 2? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 3, 2020, 3:25am UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/9 "2020-09-03T03:25:16Z")
Voyager 1 is 22 billion km away (give or take a few million km). That’s 22 quadrillion mm, so yes, the pennies would extend 6x farther than it is now. Maybe you have invented a new way to explore space! ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [September 3, 2020, 3:41am UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/10 "2020-09-03T03:41:02Z")
> [@Fiendish\_Astronaut](#): > > Apparently there is $5 trillion circulating in currency but broadly there is over $80 trillion in the world economy. If you converted all off that into pennies you’d have 80 followed by 15 zeros. That’s 80 quadrillion. ~$5 trillion is the amount of physical currency (called M0 money supply). Beyond that, there’s no single definition of “money”. Under fractional-reserve banking, a bank loan creates money from nothing since it ends up back on deposit somewhere in the banking system, and this deposit counts as part of the money supply in all measures greater than M0 (called M1, M2, etc.). So there’s really no one number you can pin down as the amount of money in the global economy. (There’s also a minor issue with your arithmetic - 100 pennies in a dollar, not 1000, so one less zero.) ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [September 3, 2020, 4:05am UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/11 "2020-09-03T04:05:23Z")
> [@beowulff](#): > > A penny is 1.52mm thick. 80 quadrillion would be 121.6 quadrillion mm. > The distance from the Earth to the Moon is 384.4 billion mm, so your stack of pennies would be 316,337x taller than necessary. In fact, the distance from the Earth to Mars (closest approach) is 54.6 million km, or 54.6 trillion mm, so your little penny tower would be around 2,000x long enough. Distance from Earth to Pluto is around 4.28 billion km, or 4.28 quadrillion mm, so your stack of pennies would reach past it into interstellar space. Using the $5 trillion value of physical currency, and taking off the erroneous extra zero from the “quadrillion” that you’re using reduces these figures by two orders of magnitude: $5 trillion = 5x10^12 dollars = 5x10^14 pennies Now doing everything in km: 1 penny is 1.5mm = 1.5x10^-6 km Our stack of pennies = 7.5x10^8 km That’s about 2000 times further than the moon, and exactly the distance to Jupiter. ---
**Author:** ![Fiendish\_Astronaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fiendish_astronaut/32/3295_2.png) [@Fiendish\_Astronaut](https://boards.straightdope.com/u/Fiendish_Astronaut)\ **Post date:** [September 3, 2020, 9:04am UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/12 "2020-09-03T09:04:36Z")
> [@Riemann](#): > > There’s also a minor issue with your arithmetic - 100 pennies in a dollar, not 1000, so one less zero. Bah - that’ll teach me to reply late at night ---
**Author:** ![ThisIsTheEnd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thisistheend/32/4713_2.png) [@ThisIsTheEnd](https://boards.straightdope.com/u/ThisIsTheEnd)\ **Post date:** [September 3, 2020, 12:02pm UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/13 "2020-09-03T12:02:01Z")
You would need a shitload of glue to keep the stack together. ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [September 3, 2020, 1:55pm UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/14 "2020-09-03T13:55:31Z")
Perhaps glue would add thickness and get us to Pluto at least. ---
**Author:** ![StarvingButStrong](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/starvingbutstrong/32/335_2.png) [@StarvingButStrong](https://boards.straightdope.com/u/StarvingButStrong)\ **Post date:** [September 3, 2020, 1:59pm UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/15 "2020-09-03T13:59:24Z")
Why are you assuming a flat stack? We’ve all probably balanced a penny on edge. I’ve seen a guy manage to balance a second penny ‘upright’ on top of another penny. So all we need is someone with REALLY steady hands and Pluto is ours! ---
**Author:** ![ThisIsTheEnd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thisistheend/32/4713_2.png) [@ThisIsTheEnd](https://boards.straightdope.com/u/ThisIsTheEnd)\ **Post date:** [September 3, 2020, 2:03pm UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/16 "2020-09-03T14:03:50Z")
Let’s say the pennies were made of something highly magnetic. How strong a magnet would you need on the earth end so that you could skip the glue? ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [September 3, 2020, 2:16pm UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/17 "2020-09-03T14:16:32Z")
> [@ThisIsTheEnd](#): > > Let’s say the pennies were made of something highly magnetic I don’t believe we have enough rare earth elements to make truly strong magnets in the quantity needed, but is there enough iron in the Earth to make these magnets? ---
**Author:** ![AlsoNamedBort](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alsonamedbort/32/3213_2.png) [@AlsoNamedBort](https://boards.straightdope.com/u/AlsoNamedBort)\ **Post date:** [September 3, 2020, 2:31pm UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/18 "2020-09-03T14:31:32Z")
> [@Si\_Amigo](#): > > I don’t believe we have enough rare earth elements to make truly strong magnets in the quantity needed, but is there enough iron in the Earth to make these magnets? According to the mint, a penny weighs 2.5 g, times 5x10^14 is 1.25x10^14 kg. Googling around iron makes up roughly 35% of the mass of the Earth, which is 5.972 × 10^24 kg, so the total mass of iron is roughly 2x10^24kg, so we have plenty. Better start digging. ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [September 3, 2020, 2:33pm UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/19 "2020-09-03T14:33:30Z")
Yes, but to make strong magnets you need Neodymium and there is not much of that here on the Earth. ---
**Author:** ![AlsoNamedBort](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alsonamedbort/32/3213_2.png) [@AlsoNamedBort](https://boards.straightdope.com/u/AlsoNamedBort)\ **Post date:** [September 3, 2020, 2:42pm UTC](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649/20 "2020-09-03T14:42:01Z")
I’m finding Neodymium makes up about .00007% of Earth, which gives us around 4x10^20 kg. Still enough. [Next page](https://boards.straightdope.com/t/if-we-converted-all-the-worlds-currency-into-pennies-how-many-would-we-have/919649.md?page=2)