Education Hub

Diamond Size Guide

Understanding how diamond carat weight translates to visual size can help you choose the diamond that best suits your style and expectations.

Diamond Size Guide

See it at its true size,
before you decide.

Carats are weight, not size. Compare any two diamonds side by side — then calibrate to your screen to view them at real, life-size scale.

Approx. scale
Round brilliant diamond A
Adjusting
Round brilliant diamond B
Adjusting

Tap a diamond, then choose its size below

≈ · adjusting Diamond A
5 ct
Want to see these at true life-size? Open this guide on your phone — it sizes the diamonds to your screen automatically.
Auto-sized to your iPhone for true life-size.
Calibrate to your screen for true life-size
  1. 1 Grab any bank card or ID — they’re all the same standard size.
  2. 2 Hold it upright against the screen (long edge top-to-bottom), inside the frame.
  3. 3 Drag the slider until the frame’s height matches your card.
Place your card here — upright
85.6 mm
shorter taller
Not calibrated yet — sizes are approximate.
CaratDiameter (mm)Looks like
0.50 ct 5.16 mm Pencil eraser
0.75 ct 5.91 mm Small pea
1.00 ct 6.50 mm Garden pea
1.50 ct 7.44 mm Blueberry
2.00 ct 8.19 mm Chickpea
2.50 ct 8.82 mm Coffee bean
3.00 ct 9.37 mm Hazelnut
4.00 ct 10.32 mm Marble
5.00 ct 11.11 mm Acorn

Diameters are typical for a well-cut round brilliant and vary with cut proportions. Calibrated true-size depends on your display; the card method keeps it accurate within a fraction of a millimetre.

How Diamond Shape Affects Visual Size

Different diamond shapes distribute weight differently, which can influence how large the stone appears.

• Oval diamonds often appear larger than round diamonds of the same carat weight.

• Emerald cuts may appear slightly larger due to their elongated shape.

• Cushion cuts sometimes appear slightly smaller because of their deeper proportions.

Choosing the right shape can influence the overall appearance of the diamond.