Skip to Content

Metric to US Conversion Charts: Simple and Effective Guide

The use of metric to US conversion charts has become increasingly important in today’s globalized world. As countries continue to interact and collaborate, it is essential for individuals to understand and navigate between the two major measurement systems, the metric system and the US customary system. The metric system, which originated in France in 1799, has become the international standard for measurement, while the US customary system, based on older English measurements, is primarily used in the United States.

In order to facilitate better communication and understanding across borders, metric to US conversion charts provide an effective and accessible means to convert between these two systems. These charts cover a wide range of measurements, including length, area, volume, mass (weight), and temperature. By presenting the information in a straightforward manner, users can quickly and easily find the appropriate conversion factors to switch between metric and US customary units.

As they are utilized in various industries, ranging from education and engineering to healthcare and cooking, the importance of metric to US conversion charts cannot be overstated. By offering a reliable resource for converting units, these charts not only eliminate confusion, but also pave the way for greater international cooperation and understanding.

Metric and US Conversion Overview

The Metric and US conversion systems serve as essential tools for expressing various types of measurements. Units from both the Metric system, also known as the International System of Units (SI), and the United States Customary system, which includes Imperial units, are used globally. It is important to understand the differences between these systems and how to convert values between them.

The Metric system is a decimal-based system, which means that its units are derived from the powers of ten. This simplifies conversions within the system, as one can easily move between units by multiplying or dividing by ten. Some common metric units include meters (length), kilograms (mass), and liters (volume).

On the other hand, the United States Customary system incorporates units that trace back to old British Imperial units. This system is not entirely decimal-based, and measurements are often in fractions. Common US Customary units include inches and feet (length), pounds and ounces (mass), and gallons and quarts (volume).

When converting between Metric and US Customary units, a unit conversion factor must be applied. These factors are numerical ratios that allow values to be transformed from one unit to another without changing the quantity being measured. Examples of these conversion factors include:

  • 1 inch = 2.54 centimeters
  • 1 meter = 3.28084 feet
  • 1 pound = 0.453592 kilograms

To simplify the conversion process, various charts and conversion tables have been developed to provide quick references. These resources typically list the corresponding unit conversions between the Metric and US Customary systems, such as:

UnitMetricUS Customary
Lengthmeterfoot, inch
Mass (Weight)kilogrampound, ounce
Volumelitergallon, quart

In addition to these charts, a multitude of online conversion calculators and tools can help users quickly and accurately convert between Metric and US Customary units. By combining one’s own knowledge base with readily available resources, efficient and accurate conversions between Metric and US Customary systems can be easily achieved.

Units of Length Conversion

Meters, Centimeters, and Millimeters

Units of length in the metric system include meters, centimeters, and millimeters. These units are related in the following manner:

  • 1 meter (m) = 100 centimeters (cm)
  • 1 centimeter = 10 millimeters (mm)

To convert between these metric units, simply multiply or divide by the appropriate conversion factor.

Inches, Feet, and Yards

In the imperial system, common length units are inches, feet, and yards. The relationship between these units is as follows:

  • 1 foot (ft) = 12 inches (in)
  • 1 yard (yd) = 3 feet

To convert between these units, multiply or divide by the relevant conversion factor.

Kilometers and Miles

Kilometers (km) and miles (mi) are common larger units of length in the metric and imperial systems, respectively. The relationship between these units is:

  • 1 kilometer = 0.621371 miles
  • 1 mile = 1.60934 kilometers

To convert between kilometers and miles, use the approximate conversion factors to multiply or divide the given value.

Approximate Conversion Factors

To convert between metric and imperial units of length, use the following approximate conversion factors:

  • 1 inch = 2.54 centimeters
  • 1 centimeter = 0.393701 inches
  • 1 foot = 0.3048 meters
  • 1 meter = 3.28084 feet
  • 1 yard = 0.9144 meters
  • 1 meter = 1.09361 yards
  • 1 mile = 1.60934 kilometers
  • 1 kilometer = 0.621371 miles

When utilizing these conversion factors, multiply the given value by the relevant factor to obtain the desired unit. Remember to remain confident in your conversions, as these factors are generally accepted for most purposes.

Units of Mass and Weight Conversion

Grams, Kilograms, and Metric Tons

Mass and weight are often used interchangeably, though mass is a measure of the amount of matter in an object while weight is the force exerted on the object due to gravity. In this section, we will focus on metric units of mass, such as grams (g), kilograms (kg), and metric tons (t).

  • 1 kilogram (kg) is equal to 1000 grams (g)
  • 1 gram (g) is equal to 0.001 kilograms (kg)
  • 1 metric ton (t) is equal to 1000 kilograms (kg)

These units can be converted between one another using simple multiplication or division. For example, to convert 500 grams to kilograms, you would divide by 1000:

500 g ÷ 1000 = 0.5 kg

Ounces, Pounds, and Short Tons

On the other hand, the US Customary and Imperial systems use units like ounces (oz), pounds (lb), and short tons (st) for mass/weight measurements. Here are some common conversions:

  • 1 pound (lb) is equal to 16 ounces (oz)
  • 1 ounce (oz) is equal to 0.0625 pounds (lb)
  • 1 short ton (st) is equal to 2000 pounds (lb)

To convert between these units, you can use a similar process as with the metric system. For example, converting 32 ounces to pounds:

32 oz × 0.0625 = 2 lb

When going from metric to US Customary/Imperial or vice versa, you can use approximate conversion factors:

  • 1 gram (g) ≈ 0.0353 ounces (oz)
  • 1 kilogram (kg) ≈ 2.2046 pounds (lb)
  • 1 metric ton (t) ≈ 1.1023 short tons (st)

These conversion factors can be used in your calculations. For instance, converting 4.5 kilograms to pounds:

4.5 kg × 2.2046 ≈ 9.92 lb

Bear in mind that these values are approximations, and your results may have varying degrees of accuracy depending on the number of significant digits used. Remember to use a reliable source and calculator to ensure accuracy in your conversions.

Units of Area Conversion

Square Meters

Square Meters (m^2) is a measurement of area in the metric system. It’s commonly used worldwide for calculating the surface of objects or spaces, such as rooms or plots of land. To convert between square meters and other units of area, you can use these approximations:

  • 1 square meter = 10,000 square centimeters (cm^2)
  • 1 square meter = 1,000,000 square millimeters (mm^2)
  • 1 square meter = 10.7639 square feet (ft^2)
  • 1 square meter = 1.19599 square yards (yd^2)


Hectares (ha) is a metric unit of area used for larger measurements of land, such as farms or large properties. One hectare equals 10,000 square meters. Here are some conversions to other units of area:

  • 1 hectare = 100 ares (a)
  • 1 hectare = 0.01 square kilometers (km^2)
  • 1 hectare = 2.47105 acres (ac)

Square Kilometers

Square Kilometers (km^2) is a metric unit of area used to measure vast areas, like the size of cities or countries. To convert square kilometers to other units of area, consider these approximations:

  • 1 square kilometer = 1,000,000 square meters (m^2)
  • 1 square kilometer = 100 hectares (ha)
  • 1 square kilometer = 0.386102 square miles (mi^2)

Square Inches

Square Inches (in^2) is a unit of area in the US Customary and Imperial systems of measurement. It’s often used for small objects or measurements. Here are some conversions to other units of area:

  • 1 square inch = 6.4516 square centimeters (cm^2)
  • 1 square inch = 0.00064516 square meters (m^2)

Square Yards

Square Yards (yd^2) is another unit of area in the US Customary and Imperial systems used for measuring larger surfaces, like carpeting or land. Some conversions to other units of area include:

  • 1 square yard = 0.836127 square meters (m^2)
  • 1 square yard = 9 square feet (ft^2)


Acres (ac) is a unit of area primarily used for measuring land in the United States and other countries using the Imperial system. Here are some conversions to other units of area:

  • 1 acre = 0.404686 hectares (ha)
  • 1 acre = 4,046.87261 square meters (m^2)
  • 1 acre = 1/640 square miles (mi^2)

Units of Volume Conversion


The litre (L) is a popular unit of volume in the metric system, with 1 litre equal to 1,000 cubic centimeters (cm³). In terms of imperial and US customary units, one can use the following conversions:

  • 1 L = 0.264172 US gallons
  • 1 L = 0.219969 UK gallons
  • 1 L = 33.814 US fluid ounces
  • 1 L = 35.1951 UK fluid ounces


A millilitre (mL) represents 1/1000 of a litre (0.001 L). Converting millilitres to other volume units results in:

  • 1 mL = 0.033814 fl oz (US)
  • 1 mL = 0.0351951 fl oz (UK)
  • 1 mL = 0.00211338 US pints
  • 1 mL = 0.00175975 UK pints

Cubic Meters

Cubic meters (m³) are the standard SI unit for volume. The conversions to other units include:

  • 1 m³ = 1,000 L
  • 1 m³ = 1,000,000 mL
  • 1 m³ = 35.3147 cubic feet
  • 1 m³ = 1.30795 cubic yards

Fluid Ounce

The fluid ounce has two different values: one for the US customary system and another for the UK imperial system.

  • 1 US fl oz = 29.5735 mL
  • 1 UK fl oz = 28.4131 mL


A pint is a unit of volume commonly used for liquids. It has different values in the US and UK systems:

  • 1 US pt = 473.176 mL
  • 1 UK pt = 568.261 mL


A quart represents a quarter of a gallon. Quart conversions include:

  • 1 US qt = 0.946353 L
  • 1 UK qt = 1.13652 L


The gallon is used for measuring large volumes of liquids. US and UK gallons have different values:

  • 1 US gal = 3.78541 L
  • 1 UK gal = 4.54609 L

Cubic Feet

The cubic foot (ft³) is a non-metric unit of volume derived from the imperial and US customary systems. Conversion figures are as follows:

  • 1 ft³ = 0.0283168 m³
  • 1 ft³ = 7.48052 US gallons
  • 1 ft³ = 28.3168 L

In summary, accurate volume conversions are essential for various applications. Understanding the relationships between litres, millilitres, and cubic meters in the metric system and fluid ounces, pints, quarts, gallons, and cubic feet in the imperial and US customary systems ensures that these values can be effectively converted as needed.

Temperature Conversions


The Celsius (°C) scale is a commonly used temperature scale and is part of the International System of Units (SI). It was initially defined by the freezing point of water (0°C) and the boiling point of water (100°C) at standard atmospheric pressure. To convert Celsius to Fahrenheit, the formula is as follows:

°F = (°C × 9/5) + 32

For example, to convert 30 degrees Celsius to Fahrenheit:

°F = (30 × 9/5) + 32 = 86°F


Fahrenheit (°F) is a temperature scale primarily used in the United States. It defines the freezing point of water as 32°F and the boiling point as 212°F at standard atmospheric pressure. To convert Fahrenheit to Celsius, use the following formula:

°C = (°F - 32) × 5/9

For example, to convert 100 degrees Fahrenheit to Celsius:

°C = (100 - 32) × 5/9 ≈ 37.78°C


The Kelvin (K) scale is the SI base unit of temperature and is widely used in scientific applications. Kelvin measurements do not use the term “degrees,” just the unit symbol K. The Kelvin scale is an absolute temperature scale, meaning it starts at absolute zero (0K), which is approximately -273.15°C. To convert Celsius to Kelvin, use the following formula:

K = °C + 273.15

For example, to convert 25 degrees Celsius to Kelvin:

K = 25 + 273.15 = 298.15K

It’s important to remember that the Celsius, Fahrenheit, and Kelvin scales each have specific use cases and are used in different contexts. The National Institute of Standards and Technology (NIST) provides guidelines, like NIST SP 365 and SI education materials, for temperature measurement and conversion best practices.

Conversion Tools and Resources

Conversion Calculators and Charts

There are several online tools and resources available to help individuals convert units between the metric and U.S. customary measurement systems. Some popular options include conversion calculators and charts that provide approximate conversion factors for common units of measurement. These tools assist users in converting length, area, mass (weight), volume, and temperature from one system to another. Calculators such as unit converters simplify the conversion process, allowing users to enter the value and select the desired unit conversion. Charts, on the other hand, provide a quick reference guide for approximate unit conversion factors.

NIST Guidelines

The National Institute of Standards and Technology (NIST) offers guidelines for constructing unit conversion problems so that one or more units can cancel until only the desired unit remains. These steps are as follows:

  1. Identify the unit you have (Starting Units)
  2. Identify the unit you want (Desired Units)
  3. Identify appropriate unit conversion factor(s)

With these guidelines, individuals can perform unit conversions with ease and confidence, whether for scientific or everyday needs.

Educational Materials

In addition to conversion calculators and charts, there are educational materials available to help individuals better understand metric to U.S. customary conversions. These resources include lessons, quizzes, and practice problems that cover various aspects of unit conversion. Through these materials, individuals can gain a deeper understanding of unit conversions and hone their skills in using conversion factors and tools effectively.