Convert Mass from Pound to Gram (lb to g)
Multiple conversions

Pound to Gram Conversion Formula

To convert from Pound (lb) to Gram (g), use the following formula:

With $453.59237$ is the ratio between the base units Gram (g) and Pound (lb).

Example

Let's convert 5 Pound (lb) to Gram (g).

Using the formula:

Therefore, 5 Pound (lb) is equal to $2267.96185$ Gram (g).

What is a Pound (lb)?

The pound (lb) is a basic unit of mass and weight in the imperial system. It's widely used in the United States and elsewhere to measure things like groceries, body weight, and shipping.

Why is a Pound Abbreviated as "lb"?

Have you ever wondered why we write "lb" for pound? The abbreviation has ancient Roman roots.

It originates from the Roman unit of mass, the libra, which is Latin for "scales" or "balance."

The whole Roman phrase was libra pondo, meaning "a pound by weight." While English speakers adopted the pondo part, which became the word "pound," the abbreviation "lb" was retained from the phrase "libra."

How Many Ounces in a Pound? Avoirdupois vs. Troy

Not all pounds are created equal. The two most common types are the avoirdupois pound and the troy pound.

• Avoirdupois Pound: This is the standard, everyday pound used for general purposes. It is equal to 16 ounces. When you weigh yourself or buy produce, you are using the avoirdupois pound.
• Troy Pound: This unit is used exclusively for weighing precious metals, such as gold and silver. A troy pound is lighter, containing only 12 troy ounces.

The Official Definition: Pound to Kilogram (kg) Conversion

To ensure global consistency, the pound is officially defined in relation to the kilogram (kg), the base unit of mass in the metric system.

Since 1959, one pound has been internationally defined as exactly 0.45359237 kilograms.

This agreement ensures that a pound in the US is the same as a pound in the UK. For everyday calculations, you can remember that 1 pound is about 0.45 kg.

What is a Gram (g)?

A gram (g) is a base unit of mass in the metric system. The plural form is grams.

Where Did the Gram Originally Come From?

The gram was initially defined in 1795 by the French National Convention.

Its first definition was based on the mass of one cubic centimeter of pure water at the temperature of its maximum density, which is approximately 4 degrees Celsius (4 °C).

This practical, water-based definition was a revolutionary step toward a standardized and universal system of measurement, moving away from the inconsistent and often confusing units of time.

Grams vs. Ounces: What's the Difference?

A gram is much smaller than an ounce, the standard unit of mass in the imperial and US customary systems.

One ounce equals approximately 28.35 grams, which is why grams are preferred for scientific work and for measuring small amounts, such as spices or medicine.

The metric system's decimal structure (for example, 1,000 grams in a kilogram) also makes calculations simpler than in the imperial system.

How Is the Gram Defined Today?

Although the gram was once tied to water, it's no longer linked to any physical object.

Since 2019, the kilogram — and therefore the gram — is defined by a fundamental constant, the Planck constant (h).

That shift makes the unit stable and reproducible in any properly equipped laboratory, without relying on the old International Prototype of the Kilogram.

What is the imperial system?

What is the metric system?

Pound to Gram Conversion Table

Here are some quick reference conversions from Pound (lb) to Gram (g):