Ring size guide: How to measure correctly (without them noticing) 2026

Finding the right size using a ring size guide is crucial to ensuring your proposal is just as perfect as you’ve dreamed it would be. There are few things that kill the mood after a ‘yes’ quite like a ring that gets stuck on the knuckle or, even worse, slips off because it’s too big.

Yet ring size is one of the trickiest things we have to deal with. Our fingers change shape throughout the day; they’re affected by the weather, diet and heart rate. Here’s a guide to help you navigate the millimetre jungle.

• Stop guessing – start observing. The most common mistake in 2026 is still trying to measure a finger with a piece of string whilst your partner is asleep. It almost never works. The string stretches, sits crookedly and rarely gives an accurate measurement.
  
  Borrow on the sly: The surest way to keep it a surprise is to ‘borrow’ a ring that your partner already wears on the right finger (the ring finger of the left hand). Take it to the jeweller or sketch the inner circumference extremely carefully onto a piece of paper.
  
  Important: Make sure the ring you borrow is actually worn on that particular finger. There’s often a big difference between the right and left hands, and between the different fingers.
  
  We asked one of Sweden’s best goldsmiths, Gunilla Lantz, who owns and runs the Smederna Lantz goldsmith’s workshop on Nybrogatan in Stockholm, for her best tips on how to measure a finger discreetly. Gunilla says: “If you can’t borrow a ring from home for a while, try the paper cone method:
  
  tape a piece of paper into a cone shape, let the ring slide down until it gets stuck, and draw a line just below it. Then hand the paper over to the goldsmith; this gives us a much more accurate measurement than a piece of string tied around your finger.
• Use technology to your advantage
  . By 2026, there will be smarter ways than going to a physical shop with a secret ring.
  
  Measurement apps: There are several reliable apps where you can place a physical ring directly on your mobile screen to get an exact measurement in millimetres.
  
  3D-printed sample rings: If you’re choosing rings together, this is worth its weight in gold. Many jewellers now send a set of simple plastic sample rings to your home. Wear them for a whole day to get a feel for how the size fits when you’re both warm and cold.
• The hidden factors (temperature and width)
  Fingers are living tissue. They’re at their smallest in the morning when it’s cold and at their largest in the evening or after a workout.
  
  Measure at the right time: The best time to measure is in the afternoon when your body is at a normal temperature.
  
  Width matters: A narrow ring band often requires a smaller size than a wide one. If you’re planning a chunky, wide ring, you’ll often need to go up 0.5 to 1 millimetre in size so that it doesn’t feel too tight.
• Allies and ‘trial shopping’
  If you’re planning a proposal and can’t get hold of a ring, ask a close friend of your partner for help. They’ll often know what’s available, or they can organise a ‘secret shopping trip’ where they try on rings just for fun.
  
  Another tip? Ask your partner to try on your ring (if you have one) and see where it sits on their finger. This gives the jeweller a good reference point to work from.
• Plan for resizing
  If you’re unsure, it’s better to choose a ring that’s slightly too big rather than one that’s too small. It’s almost always easier for a jeweller to take a ring in than to stretch it out.
  
  A word of warning about diamonds: Rings set with diamonds all the way round (eternity rings) or rings made from materials such as titanium and tungsten are extremely difficult, or even impossible, to resize. In these cases, the size must be spot on. A classic gold ring with a solitaire diamond, on the other hand, is a goldsmith’s dream – it can almost always be adjusted afterwards.

The editorial team’s final tip. The most important thing is that the ring should slide on easily, but offer a bit of resistance when passing over the knuckle.

Then you’ll know it’s secure, whether it’s a hot summer’s day or a chilly winter’s morning. And remember: if it turns out completely wrong, it’s no disaster. It just gives you a reason to visit the goldsmith together afterwards and raise a toast to the future once more.

Next step: What happens once the ring is in place? How do you ensure it continues to sparkle for another 50 years? In the final article in our series, we’ll cover everything about: After the purchase: Insurance, care and the hidden pitfalls you’ll want to avoid.