A gram is a metric unit of mass, about the mass of a paper clip. Its symbol is g. There are 1,000 grams in a kilogram and 1,000 milligrams in a gram. Grams measure light things, such as food portions, coins and letters; heavier things are measured in kilograms.
Each step up the metric mass ladder is 1,000 times bigger: milligram, gram, kilogram.
Formal definition and notation
The gram is the metric unit of mass equal to11,000 of a kilogram, the SI base unit: 1 g = 10−3 kg. Metric prefixes attach to the gram: 1 mg = 10−3 g and 1 kg = 103 g.
A kilogram is 1,000 grams, about the mass of a liter of water. Grams suit light objects; kilograms suit heavy ones.
Gramvs.Ounce
An ounce is a US customary unit of weight, about 28.35 grams. A gram is much smaller than an ounce.
Quick check: 3 questions
Question 1 of 3
How many kilograms are 4,500 grams?
Show answer and explanation
Answer: B.4,500 ÷ 1,000 = 4.5. A divides by 100, C by 10, and D by 10,000.
Question 2 of 3
Which object has a mass of about 1 gram?
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Answer: A. A paper clip is about 1 gram. A bicycle, a textbook and a watermelon are all measured in kilograms.
Question 3 of 3
How many milligrams are in 2 grams?
Show answer and explanation
Answer: D.2 × 1,000 = 2,000. A and B use 10 and 100 instead of 1,000, and C divides instead of multiplying.
Gram: frequently asked questions
How many grams are in a kilogram?
There are 1,000 grams in 1 kilogram, because the prefix kilo means 1,000. To change kilograms to grams, multiply by 1,000: 2.5 kg is 2,500 g. To change grams to kilograms, divide by 1,000: 640 g is 0.64 kg. Moving the decimal point three places does the same job.
Is a gram a unit of mass or weight?
Mass. A gram measures how much matter an object has, and that does not change if you take the object to the Moon. Weight is the pull of gravity on that mass, which does change. In everyday life people say weight when they mean mass, so a food label listing 250 g is giving the mass.
KilogramA kilogram is the base unit of mass in the metric system (SI), equal to 1,000 grams. Its symbol is kg. A liter of water has a mass of about 1 kilogram, and 1 kilogram is about 2.2 pounds. Kilograms measure heavier things, such as people, bags of flour or luggage.Measurement · Grade 3, Grade 4, Grade 5Equal ToEqual to means having exactly the same value or amount, and it is written with the symbol =. Numbers that look different can still be equal to each other: 12 is equal to 0.5. When two amounts are not the same, one is greater than or less than the other.Symbols and Notation · Kindergarten, Grade 1, Grade 2PeriodThe period of a repeating function is the horizontal length of one complete cycle: the smallest distance after which the graph repeats exactly. y = sinx and y = cosx have period 2π, or 360°, and y = tanx has period π. For y = sin(Bx) or y = cos(Bx), the period is 2π|B|.Trigonometry · Algebra 2, PrecalculusNumberA number is an amount or value used to count, measure, order and compare. We write numbers with digits (7), words (seven) or other symbols, but the number itself is the amount: 7 dots, the word seven and the numeral 7 all show the same number. Numbers include whole numbers, fractions, decimals and negatives.Number System · Kindergarten, Grade 1, Grade 2CentimeterA centimeter is a metric unit of length equal to one hundredth of a meter, about the width of a fingernail. Its symbol is cm. There are 100 centimeters in 1 meter and 10 millimeters in 1 centimeter, and 1 inch equals 2.54 centimeters.Measurement · Grade 3, Grade 4, Grade 5MeterA meter (m) is a metric unit of length equal to 100 centimeters. It is the base unit of length in the metric system, a little over three feet (about 3.28 feet). A doorway is about 2 meters tall, and 1,000 meters make a kilometer. To change meters to centimeters, multiply by 100.Measurement · Grade 3, Grade 4, Grade 5Decimal PointA decimal point is the dot that separates the whole-number part of a number from its fractional part. Digits to its left are ones, tens and hundreds; digits to its right are tenths, hundredths and thousandths. In 46.25 the point sits between 6 ones and 2 tenths, and you read it aloud as “and”.Number System · Grade 4, Grade 5, Grade 6Metric SystemThe metric system is a system of measurement in which units are related by powers of 10. Its base units are the meter for length, the gram for mass and the liter for capacity. Prefixes name larger and smaller units: kilo- means 1,000, centi- means one hundredth and milli- means one thousandth, so 1 km = 1,000 m.Measurement · Grade 4, Grade 5, Grade 6DecimalA decimal is a number written with a decimal point to show parts of a whole. Decimals use place value to represent tenths, hundredths, thousandths and more: in 3.14, the 1 means 1 tenth and the 4 means 4 hundredths. So 0.75 = 75100, and 0.5 is one half.Number System · Grade 4, Grade 5, Grade 6Unit ConversionUnit conversion is rewriting a measurement in a different unit without changing the amount, such as writing 3 feet as 36 inches. You multiply by a conversion factor, a fraction equal to 1 such as 12 in1 ft. Converting to a smaller unit gives a larger number; converting to a larger unit gives a smaller number.Measurement · Grade 4, Grade 5, Grade 6Unit PriceA unit price is the cost of one unit of something, found by dividing the total price by the number of units. For example, 18 dollars for 6 pounds is 18 ÷ 6 = 3 dollars per pound. It is the fairest way to compare products sold in different package sizes: the lower unit price costs less per unit.Ratios and Proportions · Grade 6, Grade 7, Grade 8