How to Find Out Her Ring Size Without Her Knowing

If you are planning a surprise proposal, there is one detail that worries almost everyone: her ring size. You cannot exactly ask her to try a ring on. The good news is that there are several reliable ways to work it out without giving anything away, and a small margin of error is not the disaster it feels like.

Here is how to find her ring size discreetly, how accurate you really need to be, and what to do if you get it slightly wrong.

Borrow a ring she already owns

This is the most accurate method, and the one most people overlook. Find a ring she wears on her ring finger — the left ring finger in most Western countries — and measure the inside diameter in millimetres, straight across the middle. Then match that figure against a ring size chart.

Two cautions. First, the ring has to come from the correct finger. A ring she wears on her middle or index finger will usually be one to two sizes larger, and a thumb ring is no guide at all. Second, if the ring is a wide band, it will fit more tightly than a thin one at the same size, so a wide band tends to read slightly large.

If you cannot take the ring away, press it into a bar of soap or a piece of soft putty and measure the impression later. Tracing around the inside edge on paper with a fine pencil works too.

Measure with string or a strip of paper

If there is no ring to borrow, you can measure the finger itself — though this one is harder to do unnoticed. Wrap a strip of paper or a piece of string snugly around the base of the finger, mark where it overlaps, and measure the length in millimetres. That is the circumference, and a chart will convert it to a size.

Measure at the end of the day rather than first thing in the morning, when fingers are at their smallest, and avoid measuring when her hands are cold. Both can easily put you out by half a size.

Our ring size guide has the full chart with US, UK and EU sizes alongside diameter and circumference in millimetres, so you can convert whichever measurement you end up with.

Ask someone who already knows

Her mother, her sister or her closest friend very often knows her size, or can find out in a way that will not raise an eyebrow. A friend can suggest a shopping trip, try rings on together and mention sizes out loud. It feels like cheating. It is also the single most common way people get the answer right.

If she has ever had a ring resized, the jeweller who did it may still have the record.

Look for clues she has already given you

People drop more hints than they realise. A ring that spins loosely on her finger, or one she has mentioned is too tight in summer, tells you something. So does a ring she has stopped wearing because it no longer fits. Photographs are less useful than they look, because a ring's apparent size in a picture depends entirely on the angle.

How accurate do you actually need to be?

Less accurate than you fear. Most engagement rings can be resized afterwards, typically by around two sizes up or down. The important exception is a band set with stones all the way round, or a closely set pavé band: because the diamonds are set into the metal, there is far less plain metal to work with, and resizing is usually limited to about one size either way, and needs an experienced jeweller.

That is worth bearing in mind when you choose the style. A solitaire on a plain band gives you the most room to adjust later. A pavé design is more restrictive, so it is the setting where getting the size close first time matters most.

If you are not sure, aim slightly large

Faced with a choice between two sizes, go for the larger one. A ring that is a little loose can still be worn, shown off and photographed on the day. A ring that will not pass the knuckle cannot, and that is a much harder moment to recover from.

What happens if the size is wrong

Every Claratas ring is made to order in the size you choose, so the first step is simply to tell us the size when you order. If it turns out to be wrong once she has it on, email us at contact@claratas.com and we will talk you through the options for that particular design — what can be resized, and by how much, depends on the setting.

Because pieces are handcrafted rather than taken off a shelf, it is worth allowing time. Shipping is free worldwide and fully insured, and express shipping is available for an additional $250 with delivery in five days if the proposal date is close.

A short checklist

• Borrow a ring from the correct finger and measure the inside diameter in millimetres.
• Check the measurement against a proper size chart rather than guessing.
• Measure fingers at the end of the day, never when hands are cold.
• Ask a family member or close friend — they often already know.
• If torn between two sizes, choose the larger.
• Remember that plain bands resize more easily than fully set or pavé ones.

Get the size roughly right and the proposal will be fine. When you are ready to choose the ring itself, you can browse the full range of diamond engagement rings, each made to order in 9K to 18K solid gold with your choice of natural diamond, lab-grown diamond or moissanite.