Size guides

See how big a diamond really is

Every shape and carat drawn to scale, whether a stone fits the setting you love, and how it will look on your hand — all worked out by the same code the tool runs, so a chart here and the picture on your finger never disagree.

Try it on your hand → Browse size charts

IfTheRingFits showing a 1 carat oval at true size on a hand, with a fit verdict and where to buy — The tool: a 1 ct oval at true size on a measured hand.

What the tool does

Will this diamond fit my setting?

Check a diamond and a setting go together before you buy either.

See a diamond at true size on your hand

Any shape and carat, drawn at its real size on a photo of your own hand.

Compare diamond sizes side by side

Two diamonds on the same hand at the same scale: is the bigger one worth it?

How your setting and hand change the look

Why the same diamond looks delicate on one hand and bold on another.

Size charts by shape

Every weight from 0.25 to 3 carats, to scale, with what to look for in each shape.

Round

The classic: the most sparkle, and the shape every other is measured against.

Oval

A round's sparkle in a longer outline that flatters the finger.

Cushion

A soft square or rectangle with rounded corners, like a pillow.

Pear

A teardrop: round at one end, pointed at the other.

Marquise

Long and pointed at both ends, with the most face-up size for the weight.

Emerald

Long, clean lines and a 'hall of mirrors' look.

Radiant

An emerald cut's outline with a brilliant's sparkle.

Princess

A crisp square with sharp corners and plenty of sparkle.

Asscher

A square step cut with an Art Deco 'windmill' pattern.

How big is a…

0.25 carat

4.05 mm across, round

0.5 carat

5.11 mm across, round

0.75 carat

5.85 mm across, round

1 carat

6.44 mm across, round

1.25 carat

6.93 mm across, round

1.5 carat

7.37 mm across, round

2 carat

8.11 mm across, round

2.5 carat

8.73 mm across, round

3 carat

9.28 mm across, round

Shape against shape

Oval vs Round

Which looks bigger at the same weight.

Princess vs Cushion

Which looks bigger at the same weight.

Emerald vs Radiant

Which looks bigger at the same weight.

Pear vs Marquise

Which looks bigger at the same weight.

Charts

Carat to millimeters

Every shape, every weight, in one chart.

Ring size to finger width

US sizes in millimeters, and the finger widths they imply.

Setting styles

What each style looks like, and the stones it takes.

Every shape at every weight

Oval

0.25 ct · 0.5 ct · 0.75 ct · 1 ct · 1.25 ct · 1.5 ct · 2 ct · 2.5 ct · 3 ct

Cushion

0.25 ct · 0.5 ct · 0.75 ct · 1 ct · 1.25 ct · 1.5 ct · 2 ct · 2.5 ct · 3 ct

Pear

0.25 ct · 0.5 ct · 0.75 ct · 1 ct · 1.25 ct · 1.5 ct · 2 ct · 2.5 ct · 3 ct

Marquise

0.25 ct · 0.5 ct · 0.75 ct · 1 ct · 1.25 ct · 1.5 ct · 2 ct · 2.5 ct · 3 ct

Emerald

0.25 ct · 0.5 ct · 0.75 ct · 1 ct · 1.25 ct · 1.5 ct · 2 ct · 2.5 ct · 3 ct

Radiant

0.25 ct · 0.5 ct · 0.75 ct · 1 ct · 1.25 ct · 1.5 ct · 2 ct · 2.5 ct · 3 ct

Princess

0.25 ct · 0.5 ct · 0.75 ct · 1 ct · 1.25 ct · 1.5 ct · 2 ct · 2.5 ct · 3 ct

Asscher

0.25 ct · 0.5 ct · 0.75 ct · 1 ct · 1.25 ct · 1.5 ct · 2 ct · 2.5 ct · 3 ct

See a diamond on your hand →