When thinking about creating a dream engagement ring the size of the diamond is often a key factor, with most couples looking to get the biggest looking diamond possible for their budget.

If you or your partner have their heart set on a particular diamond carat size, there are actually some diamond cuts that look and feel bigger yet have the same carat weight as others, meaning you get a bigger looking diamond for your budget.

Jewellery designer Liv Luttrell says: “When it comes to selecting a diamond, many people fixate on carat weight, but there's much more to consider. Different shapes and cuts can create varying face-up appearances. For instance, elongated rounded shapes like ovals often appear larger than their weight suggests”

But before we start, we need to understand the use of the term cut as it can be used to describe two things when discussing diamonds.

Firstly it can refer to the shape of the diamond - a round 'brilliant' cut or a square 'step cut' for example, and secondly as part of the 4Cs where it is referring to how well the stone has been physically cut - the proportions and polish of the diamond to maximise sparkle.

It’s the shape of the diamond that is the most significant factor in its perceived size, and whilst the classic round brilliant cut is a popular choice, it isn’t actually the shape that looks the biggest.

Diamond cuts that are elongated give the illusion of a bigger diamond as they have a larger surface area.

Here are 4 diamond shapes that look bigger than they really are:

The Oval diamond

An oval diamond distributes more of its weight over the top surface of the diamond, which is the bit that you actually see. This means the average 1ct round diamond is 6.4mm, but the average oval diamond length is 7.5mm.

The Pear diamond

A pear cut diamond is a hybrid between a round shape diamond, and a marquise - with a pointed tip, and a rounded base. The elongated style means you can get a much longer 1ct diamond than a 1ct round diamond.

Ring by Hannah Martin

The Marquise diamond

Because the marquise is a narrow cut with long pointed ends, the length feels much longer than other shapes and makes the marquise the shape with the biggest perceived size. 

Ring by Rachel Boston

The Radiant Diamond

Because the corners of a radiant cut diamond are cut off, you still get the length of a rectangular shape but there’s less carat weight, meaning you get a bigger stone for your budget. 

Ring by Michelle Oh

Expert Diamond buying tips:

To maximise the size when buying a diamond, look for stones that:

• Have a shallow depth percentage of around 58% to 63%, which means more of the weight is on the top flat surface (pavillion) rather than underneath (the pointed bottom bit of the diamond)

• Have a thin to medium girdle - a thick girdle takes up precious carat weight

Knowing the different cuts can really help to navigate the market and narrow down what you’re looking for but it’s also important to remember that size isn’t always the most important thing when designing a ring.

Liv Luttrell says: “I source many antique stones that often defy modern cutting standards, as they were originally crafted to be flattered by the gentle glow of candlelight. Old European cuts, for example, can be quite deep, while some elongated antique shapes are remarkably thin, offering impressive proportions and the ability to sit low on the finger.”

Remember - it’s tricky buying a diamond yourself online without experience, and only an expert can really know if a diamond is good or not. When working with a jeweller they can help advise you on the best cuts for your design and budget.

You can read more about the many factors that affect the cost of diamonds and learn more about the 4cs here