How Much Does a Nickel Weigh?
Q. How Much Does a Nickel Weigh?
John C. Dominguez Hills, California
A. One nickel weighs exactly as much as two dimes but less than a quarter. . . If you cut a quarter into 10 equal pieces, each piece would weigh 0.57 grams. If you had 75 of those pieces, the total weight would be the same as the weight of 19 dimes. This information is accurate to two decimal places, but is only the average of the three nickels I happen to have in my pocket today :) Bob Zonis Bohemia, New York 

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Actually, the precise answer would be 4.5 grams/nickel.
75 pieces (of a quarter) x .57 grams = 42.75 grams
42.75 grams / 19 dimes = 2.25 grams/dime
2.25 grams * 2 dimes (1 nickel is equal to two dimes) = 4.5 grams
This assumes the information of a quarter equaling 5.7 grams is correct.
Scott S. Bowling Green , Kentucky
5 GRAMS FOR A NICKEL, 1 GRAM FOR A DOLLAR BILL.
LARRY L. San Diego, California
Learn more: per Wikipedia:

US Coinage
Penny Standard weight 2.5 grams
Nickel Standard weight 5.0 grams
Dime Standard weight 2.268 grams
Quarter Standard weight 5.670 grams
 Norman, Oklahoma
4.9 would be the answer if you only had to go to one decimal but weigh it on a 5 decimal place scale to find a funnier one.
William J Beaverton, Oregon
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I would like to add my 2 cents in on this one.
First the weight of a penny. A penny (if you weigh 32 of them) can range in weight from 2.42 Grams to 3.18 grams the difference in the range is from .00 to .76 (from penny to penny so weigh more than one to see if your scale falls within this range) . If your scale weighs a penny and its within these acceptable ranges I would say the scale is accurate. if its out of that range I would think its off by the amount outside the range previously stated. Below 2.42 by .1 add .1 of a gram, above 3.18 subtract .1 of a gram, tare or adjust the scale to account for it.
A nickel can weigh from between 4.9 and 5.1 grams (weighed a bunch) (heard of 4.8 to 4.85 but only was able to replicate with heavily used nickels or thousands decimal place scales even then about 70 percent of the time they were between 4.9 and 5.1)(depends on the wear, if you wanted to do a real locked down test you could go to the bank and get a fresh from the press new roll of nickels or pennies for that matter). If your scale weighs within that range I would say the scale is accurate to the hundredths decimal place.
If you are just checking to see if the scale is accurate, go buy a certified 5.0 gram weight, then get a .5 gram weight, and a .55 gram weight and weigh them together, should be 6.55.
[Ed. note: see reply of June 18, 2008]
Ok, that's enough about weighing money, I went a wee bit nuts.
Mr D. Seattle, Washington
Thanks, Mr D! You rock! Laura W 
Weighing money is important and so simple...
Dimes, quarters and half dollars are $20/lb, and
nickels are only $5/lb, and
there are 181 pennies/lb ($1.81) and nobody seems to pick up on this simplicity...
Furthermore currency is 6.2"x 2.6" x 0.0043" thick (233/inch) and it takes 375 bills to weigh a lb. Therefore, a briefcase 18.5"x 12.5"x 3" thick will hold $980,000 in $100 bills (two rows of seven [14 stacks] x 3" [700 bills/stack] = $980,000.
And it will weigh 26.1 lbs (375 bills/lb).
I know this because I am a father to my inquisitive children.
 Davenport, Iowa
And here we thought that you knew only $980,000 would fit in a briefcase from countin' the loot :) I was just about to offer to take the remaining $20,000 off your hands so you wouldn't need to carry a second briefcase.
Rock with Katie Holmes & Queen Lativa, I loved it => 
Mad Money 
So a penny weighs 2 grams. In our science class we measured it and it weighed 0.2 grams Maria G Chicago, Illinois Somebody misread the scale, Maria. Depending on how the scale is designed, the mass of the balance weight is not necessarily the weight of the item you are balancing against. Nurses would have a hard time weighing us if they had to slide a 200pound balance weight along their beam scale :) Maybe that was the weight of the balance weight?

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For the accurate weight of any coin, and other nifty facts about money just go to the website for the U.S. Mint at this website address:
www.usmint.gov/about_the_mint/index.cfm?action%3Dcoin_specifications
Enjoy!
Mike
 Iowa City, Iowa
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Regarding COINS, the PENNY only weighs 2.5 grams ($1.82/lb) and NICKELS weigh 5.0 grams each... and as mentioned earlier, DIMES, QUARTERS, 1/2 DOLLARS and Eisenhower DOLLARS are all worth $20.00/lb  NICKELS, on the other hand, weighing 1.0 gram/cent (5 grams total, each)  since there are 453.6 grams per lb, a pound of NICKELS is only $4.54/lb... all parents need to know these simplistic facts because our children are going to inherit the earth  teach them! It's fun, and fun for them to share with their friends!
Terry H Davenport, Iowa
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As far as the exact weight of various coinage it is really hard to say. Even if the are fresh from the mint there are so many variables. The best thing to do is way multiple coins and average them. The more coins the more inclusive your answer. On most coins the % error is due to mostly wear, dirt or even finger prints so be sure to wash and handle with care. The penny will have the largest % error (over %23) due to the change in materials used over the years. The rest of your coinage should be between %10%15 error. The average weight of used currency...
P=2.637953, N=5.011551, D=2.278447 and Q=5.6792
Have Fun!
 Grand Blanc, Michigan
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As Erik mentioned, the composition of coins has changed over the years.
Anyone interested in weighing PENNIES should be aware that the composition of pennies changed in 1982. For dates of 1982 and earlier, pennies are 95% copper and 5% zinc and weigh about 3.1 grams. For dates of 1982 and later, pennies are 97.6% zinc, and 2.4% copper and weigh about 2.5 grams.
1982 was a transition year during which the U.S. mint issued BOTH varieties of pennies.
You can easily verify the weight difference, even if you don't have a scale. You can make your own balance beam using a thin, rigid 12inch ruler. Place a stack of five pennies issued BEFORE 1982 precisely at the end of the 12inch ruler. Place a stack of five pennies issued AFTER 1982 precisely at the other end of the ruler. Holding both ends of the ruler, place the ruler on the edge of a butter knife (or some other thin flat object) so that the 6inch mark is lined up precisely with the edge of the knife. (You can support the butter knife between two books so that the blade stands upright.) When you release the ends of the ruler, you'll see that the end with the pre1982 pennies will go down, and the end with the post1982 pennies will go up. That's exactly what you'd expect, since copper is more dense than zinc.
There have been other variations in U.S. coin composition (most notably, the change in composition of dimes and quarters in 1965, replacing silver with copper and nickel).
For more info, see the U.S. Mint website:
www.usmint.gov/about_the_mint/mint_history/index.cfm?flash=yes&action=coin_composition
 New York, New York
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Yep, my scale's right! 5 grams! Thank you! Lindsey S Kaufman, Texas +++++++ Thanks, Gregor Clark, you rock! Mark T Montgomery, Alabama +++++++ All you guys rock. Thank you all for giving this serious thought. Accuracy is essential. Peace. Danielle H Eugene, Washington 
"Handson" learning is fun, maybe try a precision scale? . . . Electronic scale 
June 18, 2008
MR D  You seem like a smart guy with all those measurements and stuff but how do you get 6.55 when you add 5.0 + .5 + .55. I'm pretty sure that every time I do that it's going to come out to 6.05 :)
Seth H Merrimac, Massachusetts
May 6, 2009
What is the volume of a nickel?
Walter W Brook Park, Ohio
May 12, 2009
You can actually measure the diameter and thickness of a nickel and calculate the volume, Walter. Or you can use Archimedes' principle and measure the volume of water that the nickel displaces. Or you can divide its 5.0 gram weight by the density of nickel for a good approximation. Do it all three ways and maybe you have an interesting science project.
Regards,
Ted Mooney, P.E. RET finishing.com Brick, New Jersey 
Try more project ideas:
 What cleans pennies best?,
 How does electroplating work?