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Getting a True Measure

Bureau of Weights & Measures

It's hard to be a smart consumer today. Think about the products you buy and the amount you can spend. Can I afford this? Is this the best buy? Am I getting my money's worth? Almost everything we buy is sold by weight, volume, length, count or measure. For example, a dozen eggs, a gallon of milk, a liter of wine, a yard of cloth, a pound of hamburger and a cord of firewood are all sold by either measurement, weight, volume or length. Without standard measurements, it would be difficult to do even simple things like use cookbooks or buy carpeting, laundry detergent and fabric.

Keeping the market in balance:

  • You don't carry a scale or measuring tape with you to check the weight or measure of everything you buy. How do you know you're getting what you pay for? For a number of years, the weights and measures officials at the Illinois Department of Agriculture have been working behind the scenes to protect consumers, businesses and manufacturers from unfair practices. These men and women use highly accurate equipment to inspect scales, meters and prepackaged products at supermarkets. 
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    hey also inspect weighing and measuring equipment and packages at warehouses, packing plants, feed mills, shipping companies, lumber yards and gasoline stations. They act as a third party to help maintain fairness and keep the marketplace in balance. The state maintains a metrology laboratory which has a set of weights and measures standards. These are used to check the accuracy of the equipment used by weights and measures officials and industry. 

Know your rights and responsibilities: 

  • Consumers have rights and responsibilities in the marketplace. The following information provides important ideas about how to use weights and measures information. 

Read the label: 

  • Package labels give consumers helpful information. The amount of the product or the net quantity in the package ​is

    marked on the label. The quantity is shown as a weight, measure or count, such as ounces, pounds, quarts, liters or square feet. 

Pay only for the product, not the packaging: 

  • When you buy apples in a plastic bag, you should pay only for the weight of the apples. If you buy potato salad at the deli counter, you should pay for the salad and not for the weight of the container. In many stores, the electronic or computerized scales used at the check-out counter are set to automatically deduct the packaging materials. Scales must be placed so you can see the weight.
  • If you have a question, ask to have the package weighed again before you buy. Ask if the weight of the packaging has been deducted. Weights and measures inspectors visit stores to inspect and weigh prepackaged products. They also check the accuracy of the scales being used. 

What you can do:

  • Watch the scale and the amount registered. The scale should be placed so you can see the weight, price and other information displayed.
  • Make sure the scale shows a zero or minus sign before anything is weighed. Pay only for the product, not for the packaging.
  • If you have any questions about how a store weighs or measures products, ask the manager for information first. He or she should answer your questions.

Compare products and prices, and use unit pricing:

  • Food is a large part of a family budget. To make the best choices and to get the most for your money, it is important to compare the price, amount and quality of similar products. Unit pricing can help. The unit price tells you the costs per "unit" (such as per ounce, per pound, per sheet) to buy the product. It's easy to find the unit price of some items. It may be marked on a sign near the item. For example:
    • If apples sell for $.89 per pound, you know that 5 pounds will cost $4.45 (5 pounds x 89 cents).
    • If potato salad sells at the deli counter for $2.59 per pound, you know that 2 pounds will cost $5.18 (2 x $2.59).
  • Unit pricing is most helpful when the price per unit isn't so clear. For example, your favorite brand of corn flakes is sold in three different sizes: the 14-ounce box is $2.52; the 20-ounce box is $3.00; and the 2-pound (32-ounce) box is $5.12. Which one is the best buy? Unit pricing helps. (In this case, the unit price is the price per ounce.) To figure the unit price, divide the price by the number of units (in this example, it's the number of ounces.)
    • The unit price for the 14-ounce box is 18 cents per ounce ($2.52/14)
    • The unit price for the 20-ounce box is 15 cents per ounce ($3.00/20)
    • The unit price for the 2-pound box is 16 cents per ounce (2 pounds = 32 ounces; $5.12/32)
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    n this example, the 20-ounce package is the best buy because it costs less per ounce. Remember, the larger package in not always the best buy. It pays to know the unit price. Corn flakes are also sold in the bulk food section for $1.44 per pound (one pound = 16 ounces). Divide $1.44 by 16, and you know the cost per ounce is 9 cents. How does the unit price of the boxed corn flakes compare with the unit price of the corn flakes sold in the bulk food section? In this example, the unit price shows that the corn flakes from the bulk food section are the better buy. 

  • What you can do:

    • Look for unit price labels on shelves or signs near the items.
    • Compare the unit price of similar products to find the best buy.
    • If the unit price is incorrect, report it to the store manager. Ask the manager to correct the unit price information.

When buying gasoline:

  • Good measurement is also important when you buy gasoline and motor fuel. These fuels are sold by volume in gallons or liters. The price you pay for gasoline will depend upon:
    • The octane level, which may affect the performance of your car.
    • The amount you buy.
    • Any discounts offered.
  • In many areas, they also check gasoline storage tanks to be sure that stations are selling the octane level advertised. If violations are found, the seller can be fined and the product can be removed. Gasoline stations may offer a discount if you pay cash instead of using a credit card. This cash discount is usually 2 to 8 cents per gallon off the regular price. On some pumps, you may be able to push a button to automatically show the discounted price. In some cases, the attendant must figure out the cash discount and deduct it from the price showing on the pump. To figure the cash discount in this situation:
    • Multiply the number of gallons or liters you purchase by the credit price per gallon or liter. This should be the total price showing on the pump.
    • Multiply the cash discount times the number of gallons or liters you purchase. This is your total cash discount.
    • Subtract the total cash discount from the total price shown on the pump.
  • What you can do:

    • Be sure the attendant or you are using the correct pump. The octane rating and the price per gallon or liter should be clearly marked on each pump.
    • Be sure the pump is set to zero before any gasoline is pumped.
    • Check the price by multiplying the number of gallons or liters by the unit price. Be sure this shows as the total due.
    • Figure the cash discount, if any. Check that you are charged the right amount.
    • If using a credit card, check your receipt to be sure the amount billed is the amount on the pump. Take your card and any carbon paper from the credit slip.

When buying heating fuel:

  • Home heating fuel and propane are also sold by volume or weight. When these products are delivered to your home, the seller must give you a "delivery ticket" showing the name and address of the buyer and the seller, the delivery date, and the amount and type of fuel delivered. The unit price of the fuel should also be on the delivery ticket unless you have a special arrangement with the seller. 

When buying firewood:

  • Some people heat their homes with firewood. Firewood is sold by a measurement called a "cord." A cord is 128 cubic feet of firewood. To be sure you have a cord, you can stack and measure the wood. For example, a cord of firewood, when stacked, could be a pile that is 4 feet wide, 4 feet high and 8 feet long; or 2 feet wide, 4 feet high and 16 feet long. You can stack the wood in other ways, too. If the width times the height times the length (all in feet) equals 128 cubic feet, you have a cord of firewood. The use of terms such as "truckload," "face cord," "rack" or "pile" as the method of sale of firewood is not allowed. Firewood is to be sold by the cord or fractions of a cord (such as "half of a cord" or "quarter of a cord"). 
  • What you can do:
    • When you buy firewood, ask the seller to stack the wood (you may have to pay extra for this service) or stack the wood yourself.
    • Get a receipt which shows the seller's name, address and phone number, and the price, amount and kind of wood purchased. Write down the license number of the delivery vehicle.
    • Measure the wood before using any.
    • Take a picture of the stack if you think there is less than a cord.
    • If you feel you have a problem, contact the seller before you burn any wood.

Weights and measures is everyone's business:

  • State and local weights and measures officials are working behind the scenes to protect you. Consumers and businesses both benefit and can help their local weights and measures officials enforce the law and help maintain a fair marketplace. 

Look for decals:

  • Illinois Department of Agriculture inspectors test weighing and measuring devices such as gasoline pumps and scales. A decal is put on the device to indicate the equipment was tested and found correct. If you have a problem with weights and measures or motor fuel quality, talk to the store manager or owner. Give them a chance to correct the problem. If the manager can't or won't resolve the problem or answer questions to your satisfaction, contact the Illinois Department of Agriculture by calling the toll-free hot line listed on the decal: 1-800-582-0468. 

Use what you learned--test your skills on these examples: 

  • 1) You need to buy 3 yards of rope. The hardware store sells the rope for $2.50 per yard. What is the cost? 2) You go to the supermarket to buy dog food. The 10-pound bag costs $6.90. The 4-pound bag is marked $4.40. Which is the better buy? 3) You buy 15 gallons of gasoline at $1.39 per gallon (credit price). There is a 4 cent-per-gallon cash discount. What should you pay if you use a credit card? What should you pay if you use cash? 4) You have 350 gallons of heating oil delivered to your home. What should you look for on the delivery ticket? 
    • ​​Answers:


      1) $7.50 (3 yards x $2.50 = $7.50) 2) The 10-pound bag which costs 69 cents per pound ($6.90/10 = $.69 per pound; $4.40/4 = $1.10 per pound) 3) If you use a credit card, you should pay $20.85 (15 gallons x $1.39 = $20.85). If you use cash, you should pay $20.25 (15 gallons x $.04 = $.60 discount) ($20.85 - $.60 = $20.25). 4) The seller's name and address; your name and address; the delivery date; the amount sold (350 gallons); the type of fuel (home heating oil); the unit of price. 

Metric is coming:


    Today, many products are labeled and sold in metric measurements. The metric system is based on tens and is already used in most of the world. Film, soft drinks, wines and alcoholic beverages, tools and bicycles are now sold in metric measurements. Metric measurements are noted in liters, grams and meters or variations of these units, such as milliliters, kilograms and centimeters. 

  • METER = measurement of length and area (square meter). In the future, you'll see this in fabric or carpet stores and for measuring distance. A meter is a little longer than a yard. LITER = measurement of volume. You already see this on beverages; in the future, you'll see this on gasoline pumps. A liter is a little larger than a quart. GRAM = measurement of mass (weight). You already see this on many food packages. In the future, you'll see this at the deli and meat counter. A gram is a little more than the weight of a paper clip.

                                                                                    Metric Conversion Chart
  When You Know Multiply by to Find Symbol
Length inches 2.5 centimeters cm
feet 30.5 centimeters cm
yards .9 meters m
miles 1.6 kilometers km
Area square inches 6.5 square centimeters cm*
square feet .009 square meters m*
square yards .8 square meters m*
square miles 2.6 square kilometers km*
acres .04 hectares ha
Mass (weight) ounces 28 grams g
pounds .45 kilograms kg
short tons (2000 lbs.) .9 metric ton t
Volume teaspoons 5 milliliters mL
tablespoons 15 milliliters mL
cubic inches 16.4 milliliters mL
fluid ounces 30 milliliters mL
cups .24 liters L
pints .47 liters L
quarts .95 liters L
gallons 3.8 liters L

*Note: All conversion factors in this table are approximate because they have been rounded off to simplify calculations. A cubic centimeter (cc) is the same as a milliliter.

For more information, contact: 

Illinois Department of Agriculture
Bureau of Weights and Measures
P.O. Box 19281
State Fairgrounds
Springfield, IL 62794-9281

1.800.582.0468 (in Illinois)

TDD 866.287.2999
FAX 217.524.7801