There are several ways to find her ring size without asking, and the methods below run from most accurate to last resort:

1. Borrow a ring she already wears and measure the inside of the band.
2. Trace the inside of one of her rings on paper.
3. Press a ring into a bar of soap and measure the imprint.
4. Recruit her best friend, sister, or mom.
5. Send a free ring sizer to your accomplice.
6. Ask about a fake gift, like a ring for your mom.
7. Fall back on the averages and size up.

Borrow a ring she already wears

The gold standard. Take a ring she wears on the target finger and note which finger it comes from. Measure the inside of the band edge to edge in millimeters. Match that number on the Foreverings ring sizer page, where a calibrated on-screen dial converts it to her exact size in seconds. And if you can get the ring out of the house without her noticing, take it to a jeweler. They can measure it on a ring mandrel, a tapered sizing rod. That is the most exact reading you can get.

Just be careful which ring you take. Borrow a ring she will not miss for a few hours, not a daily wearer. And only trust rings from the correct finger, because sizes vary between fingers and even between hands.

Trace or imprint a ring you cannot take

If removing a ring feels risky, trace it. Lay it on paper and draw the inside circle carefully with a sharp pencil, twice. Or press it gently into a bar of soap and measure the circular imprint.

A tracing is less exact than a measurement, so treat the result as a starting point and size up if it lands between sizes. To turn a guess into a real measurement later, our guide on how to measure ring size at home walks through the accurate methods.

Ask her best friend, sister, or mom

Her best friend, her sister, her mom. Someone in that circle either knows her ring size or can find out over coffee without raising an eyebrow. This tactic also buys you a second opinion on the ring style itself.

Pick one accomplice, not three. Every extra person who knows is another chance the surprise leaks.

Have a friend size her finger

Order our plastic dial ring sizer, which is free.

Someone has to get it onto her hand.

That someone is usually the sister or best friend from a few sections up. A friend can hold her hand out and try things on without it registering as odd. She can do it at the end of the day, when her fingers are their normal size. Have the sizer shipped to them directly.

The packaging is plain, but if it comes to your house instead, intercept the mail as to not ruin the surprise.

Ask about a ring for someone else

Tell her you are buying a ring for your mom or your sister and ask what size she wears so you can gauge it. It reads as harmless because it is the kind of thing people genuinely ask.

This one takes acting. If you do not feel comfortable pulling it off, recruit an accomplice to find her size the way the tactic above describes. That keeps the surprise safe if she starts to get suspicious. And if secrecy falls apart entirely, you are in good company. As The Knot’s engagement ring guide notes, plenty of couples now pick the ring together on purpose.

Fall back on the averages, then size up

No ring to borrow, no accomplice, no time? In our orders, the most common women's ring size is a 7, and most women fall between a 6 and an 8.5. Our average ring size guide has the full breakdown. When in doubt, size up. A loose ring can be exchanged for her size. A ring that will not go over her knuckle ends the moment.

What if you get her ring size wrong?

You planned for this by choosing well. Foreverings offers size exchanges on orders that fall within our exchange policy. If you are unsure of the size, skip the engraving for now so the ring can be exchanged later. Grab the free ring sizer tools to confirm what you learned, and go get the yes.