The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Test Digital Scale Calibration With Coins

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Antilope's picture
Antilope

Test Digital Scale Calibration With Coins

To test a digital scale if you don't have a special calibration weight you can use coins: (Make sure to use new, shiny coins. Worn coins will weigh less).
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A U.S. nickel (5-cent coin for non-Americans) weighs exactly 5.00 grams and a U.S. cent (since 1983) weighs exactly 2.50 grams.
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U.S. Cents 1981 and before weigh 3.11 grams. (In 1982 solid bronze U.S. cents were replaced with copper plated zinc U.S. cents. In 1982 both metal types of U.S. cents were made.)
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Here is the U.S. Mint web page on coin specifications. Cent through dollar coin weight in grams:
http://www.usmint.gov/about_the_mint/?action=coin_specifications
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Cent (since 1983) - 2.500 g
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Nickel (since 1866) - 5.000 g
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Dime (since 1965) - 2.268 g
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Quarter (since 1965) - 5.670 g
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Half Dollar (since 1971) - 11.340 g
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Golden Dollar Coin (since 2000) - 8.1 g
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Silver American Eagle Collectors Dollar - 31.103 g (1.00 troy oz)
http://www.usmint.gov/downloads/mint_programs/am_eagles/AMERSILVREAGLE.pdf
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Canadian coins are lighter. A Canadian 5-cent coin weighs 3.95 grams since 2000. A Canadian 1-cent coin weights 2.35 grams since 2000. Before 2000 coin weights changed several times due to changes in metal content.
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If you live in another country, check out your government mint web site or coin collectors web sites for gram weights of your local coins.

cranbo's picture
cranbo

This is a good tip, thanks for the reminder. The same tip to use nickels for calibration came with my MyWeigh digital scale. 

MisterTT's picture
MisterTT

Coins are interesting, but it is a bit of a hassle to pester everyone in the household if they have a newly minted coin. Another thing is that, for example, in my country the mass of coins is pretty much a random variable: one Lithuanian cent weighs 0.83 grams and so on.

So, for ease and convenience I do this: for small masses, take a syringe (everyone has a syringe), put it on the scale and zero it, then take it off and draw, for example, 5 ml of water and put the filled syringe back on the scale and see if it weighs five grams. For larger masses a measuring cup or a beer glass can be used.

Syringes are reliable because their manufacturers cannot screw up the volume marks - it might mean life and death. Measuring cups and beer glasses not always so. Yes, there are some minerals dissolved in tap water which change its density, but the change is very slight, especially compared to coin wear.

Antilope's picture
Antilope

That's a good idea using a syringe to measure water to determine correct weight. We should not use our kitchen measuring spoons or cups because many are very inaccurate. Cook's Illustrated did a test of various brands of measuring spoons and cups and found many to be inaccurate.

kph1956's picture
kph1956

According to the UK Royal Mint web site (http://www.royalmint.com/discover/uk-coins/coin-design-and-specifications/twenty-pence-coin) 20p coin weighs 5g. Other coin values are also given.

My basic and cheap Asda scales recorded correct weights as I placed three coins on them, 5g, 10g, 15g. However my wifes expensive WeightWatchers scales (6x as expensive) wouldn't register until two coins were placed on them, though they did record the correct weight of 10g and 15g when three coins were used

Antilope's picture
Antilope

I have to say, that is a beautiful coin design. It's good to know that a scale you are using is correct. This is an easy way to accomplish that.