The Weight of a Diamond: Understanding Carat Weight

Among the five key characteristics of diamonds—known as the 5 Cs—carat weight is the simplest and most straightforward factor used to determine a diamond’s value. Carat weight measures the actual weight of the diamond and directly correlates with its size.

What is a Carat?

A carat is a unit of weight used for diamonds and other precious gemstones. One carat is equivalent to 200 milligrams, or one-fifth of a gram, which is also approximately 0.007 ounces. To provide even more precision, one carat is divided into 100 points. Therefore, a diamond that weighs 0.75 carats, or 75 points, is often referred to as a three-quarter carat diamond.

Carat Weight and Pricing

As diamonds increase in weight, their price per carat rises exponentially rather than linearly. This means that a two-carat diamond is typically far more than double the price of a one-carat diamond of the same quality. The primary reason for this steep price increase is the rarity of larger diamonds.

For example, here are some current price ranges based on carat weight and quality:

  • 1/2-carat: $1,500 to $4,000
  • 3/4-carat: $3,000 to $6,500
  • 1-carat: $5,000 to $15,000
  • 2-carat: $15,000 to $50,000

Factors Influencing Carat Weight Price Increases

Several factors contribute to the geometric price increase as carat weight goes up:

  1. Rarity: Larger diamonds are significantly rarer than smaller ones. As the carat weight increases, the availability of diamonds that size decreases.
  2. Demand: There is a high demand for larger diamonds, particularly for engagement rings and significant jewelry pieces, which drives prices higher.
  3. Cut Quality: Larger diamonds often require more skillful cutting to maintain quality, impacting their final price.

Measuring Carat Weight

Diamonds are accurately weighed on calibrated scales to ensure precision. This process typically occurs when the diamond is loose, meaning it is not set in any mounting or jewelry piece. Accurate measurement is crucial because even a slight difference in carat weight can significantly impact the diamond’s value.

Examples of Carat Weight and Value

  • 1/2-carat diamond: Typically found in delicate jewelry, these diamonds are perfect for understated elegance. Priced between $1,500 and $4,000, they offer a balance between size and affordability.
  • 3/4-carat diamond: A popular choice for those looking to make a statement without reaching the one-carat mark. These diamonds range from $3,000 to $6,500.
  • 1-carat diamond: A benchmark for many, representing significant value and presence. Prices range from $5,000 to $15,000, depending on quality.
  • 2-carat diamond: A truly exceptional stone, often reserved for special occasions. The price can range from $15,000 to $50,000, reflecting its rarity and desirability.


Understanding carat weight is crucial for anyone looking to purchase a diamond. It not only affects the size and appearance of the diamond but also its price significantly. By recognizing how carat weight influences value and considering the geometric price increases, consumers can make more informed decisions when selecting their perfect diamond. Accurate measurement and knowledge of the market ensure that buyers can appreciate the true worth of these stunning gemstones.