How to determine the measurement of a finger turn for a diamond ring ?

How to measure your ring size

Knowing your correct ring size is essential for finding the perfect fit, whether you're choosing an engagement ring, a diamond solitaire or a wedding band. To help you determine your ring size easily and accurately, i-diamants offers a free printable ring size guide, available to download in just one click.

⬇ Download our free ring size guide (PDF)

With this guide, you can measure the inside diameter of a ring you already own and find the corresponding size. You'll also discover helpful tips for taking accurate measurements, avoiding common sizing mistakes and choosing your diamond ring with confidence.

Free PDF · Print at actual size (100% scale)

There are several ways to determine your ring size. One of the easiest and most reliable methods at home is to use a ring you already wear and compare its inside diameter with our printable ring size guide. If you don't have a suitable ring, you can also measure the circumference of your finger directly.

Our tips for choosing the right ring size

Even with accurate measurements, a few simple precautions can help you avoid sizing mistakes and ensure a comfortable fit. Here are our diamond experts' recommendations for finding the right ring size.

When is the best time to measure your finger?

Finger size can vary slightly depending on temperature, physical activity and the time of day. For a more reliable measurement, we recommend measuring your finger towards the end of the day, at room temperature, and avoiding times when your hands are particularly cold or swollen.

Always measure the finger on the hand where you intend to wear your ring, as sizes may differ between your left and right hands.

What if you're between two ring sizes?

A properly fitted ring should slide over your knuckle comfortably while remaining secure on your finger. If your measurement falls between two sizes, choosing a slightly larger size may be appropriate, depending on the shape of your finger and the width of the band.

Wider rings can feel tighter than delicate bands. If you're unsure, we recommend having your ring size checked by a professional jeweller.

How can you find someone's ring size for a surprise?

Planning a surprise proposal or looking for the perfect diamond engagement ring? The easiest solution is to discreetly borrow a ring that your loved one already wears on the same finger and measure its inside diameter using our printable ring size guide.

You can also ask a close friend or family member for advice, or contact our diamond experts for personalised assistance.

Need help finding your ring size?

Our team is here to guide you before placing your order and explain the resizing options available for your chosen ring.

Contact our diamond experts →

Ring sizes vary from country to country. In France and many European countries, ring sizes correspond to the inner circumference of the ring in millimetres. The United States uses a numerical sizing system, while the United Kingdom uses letters.

Use our conversion chart to compare French/EU, US and UK ring sizes. These conversions are approximate. For the most accurate fit, we recommend checking your measurements with our free printable ring size guide before ordering your i-diamants ring.

Correspondances indicatives. Pour une mesure précise, utilisez notre baguier à imprimer.

At i-diamants, intermediate ring sizes may be available for a more precise fit. If your ring doesn't fit perfectly after delivery, resizing may also be possible, depending on the design and applicable conditions.

Learn more about ring resizing →