The Diamond Pro

Ring Size Guide: How to Find Your Ideal Ring Size

By Michael Fried
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Bottom Line Recommendation:

For the most accurate ring size, we recommend ordering a complimentary plastic ring sizer from either Blue Nile or James Allen. These ring sizers work better than paper and string which can both stretch—causing an inaccurate measurement. You can also measure the inside diameter of an existing ring and compare it to a ring size chart like the one below. 

We also suggest buying a diamond ring from a reputable vendor who offers a complimentary ring resize like James Allen and Blue Nile.

Whether you’re shopping for the perfect engagement ring or an anniversary ring or eternity band, you’ll need to know the correct ring size. And if you’re planning a surprise proposal, you’ll need this information well in advance.

Luckily, there are several ways to determine the ideal ring size for your special someone. While you can always get the ring resized if it’s not quite right, the excitement of wearing the ring proves better if you have the correct size from the start.

Our guide includes a ring size chart, insider tips on measuring and the best places to buy a diamond ring once you know the size.

How to Determine Ring Size

Need to know the ring size of the one you love? Try any of the following methods.

  • For the most accurate method, order a complimentary ring sizer from James Allen or Blue Nile. Either website will send you a free plastic ring sizer in the mail.

    An Amazon Ring Size Set Example Here

    Experts suggest avoiding using paper or string to measure ring size. Both materials can stretch or twist, causing your measurement to be inaccurate. James Allen also offers a complimentary online sizing tool here.  If you feel like you want something nicer because you’ll use it more than once, there are ring size sets being sold on Amazon for a few bucks.

  • Match the size of an existing ring—whether that’s a class ring or an engagement ring. Measure the inside diameter and compare it with a plastic ring sizer or printable ring sizing chart  (like the one below). Another option is to go to Amazon again and look for a ring size measuring stick. This can be very useful even after your engagement when you decide to surprise your partner with another ring at any point in your life together.
  • Measure the wearer’s ring finger with paper and compare it with a ring size chart. You can use a free printable ring sizer or a thin piece of paper (however, we suggest a free plastic ring sizer ahead using these methods). Wrap the piece of paper around the finger, then mark the spot where the paper overlaps. Measure the length with a ruler and compare to a ring size chart (below). If he or she is a heavy sleeper, and you want to measure in sneaky fashion, try wrapping a string around their ring finger during the night. Pinch the point where the ends meet, then compare the measurement to the chart.
  • Visit a jewelry store for a professional measurement.
  • Have a close friend or family member gather the ring size information for you. Parents or friends may have purchased jewelry from them in the past, or have access to their jewelry collection. They can also covertly ask for their ring size (just in case you ‘happen’ to propose).

Your Engagement Ring Can Be Resized

Remember that not knowing the ring size doesn’t have to spoil your proposal plan. Go with your best estimate using the ideas above, and opt for a half size up when in doubt.

The ring can also be resized after the proposal. Most diamond sellers, like Blue Nile and James Allen, offer complimentary ring resizing within a certain time frame. Be sure to know ahead of time what the free resize period is at your particular vendor so you don’t miss out on this service.

Ring Size Chart and How to Use It

As mentioned above, we suggest ordering a complimentary plastic ring sizer from Blue Nile or James Allen.Or you can get one of the tools from Amazon.

Amazon Size Measuring Stick

Any of these tools help you measure a finger or an existing ring.

But no matter how you receive your measurement, you can use the chart below to determine the proper size.

If you have a measurement for the ring finger’s diameter, use the circumference column.

If you have a measurement for a ring’s diameter, use the diameter column.

International Ring Size Chart

Circumference (mm)Diameter (mm)UK, Europe, AustraliaUnited States & CanadaChina, Singapore, JapanHong KongSwitzerland
44.814.3F  1/255  1/4
45.514.5G3  1/27.5
46.114.7G  1/266  1/2
47.415.1H  1/27  3/4
48.015.3I4  1/2810
49.315.7J  1/25911
50.015.9K11  3/4
50.616.1K  1/25  1/21012
51.216.3L11  3/4
51.916.5L  1/26111312  3/4
53.116.9M  1/26  1/21314.514
54.417.3N  1/27141615  1/4
55.717.7)  1/27  1/2151716  1/2
57.018.1P  1/281617  3/4
58.318.5Q  1/28  1/21719
59.519.0R  1/291820.5
60.219.2S20  1/4
60.819.4S  1/29  1/21922
61.419.6T21  1/2
62.119.8T  1/2102023
63.420.2U  1/210  1/2222422  3/4
64.620.6V  1/2112325
65.921.0W  1/211  1/22426
67.221.4X  1/2122527.7527  1/2
68.521.8Z12  1/22628  3/4
69.122.0Z  1/2
71.022.613  1/2

*Data from the Blue Nile International Ring Size Chart

Common Ring Sizes

While women’s ring sizes typically range from size 3 to 9, most rings ordered are sized 5 to 7—with size 6 being the most popular.

Men’s sizes generally range from size 8 to 14, with most falling somewhere between 8 and 10.5. For men, size 9 is the most popular.

Pro Tips for Ring Finger Measuring

Calculating ring size is pretty straightforward, but you should still keep in mind the following tips to ensure your measurement is as accurate as possible.

  • Be sure the finger is at normal or slightly elevated body temperature, as fingers shrink and expand when hot or cold. The best time for the most accurate sizing is near the end of the day when the fingers are warm. When the hands are cold, like they often are in the morning, the fingers will measure smaller.
  • Measure the finger three to four times to prevent inaccuracies.
  • Use a plastic ring sizer rather than a piece of paper or string, as these can bend or stretch and create inaccuracies.
  • Measure the finger you’re intending to wear the ring on. Left-hand and right-hand ring fingers can differ in size.
  • If the knuckle is noticeably larger than the base of your finger, record both measurements and choose a ring size that’s in-between the two. The ring should slide over the knuckle, but shouldn’t be so loose that you’ll risk having it slip off or move around excessively.
  • It’s critical that the ring fits tightly over the knuckle to prevent the ring from falling off. It shouldn’t be too tight, though, where blood flow is restricted.
  • Wider bands (those 6mm or wider) tend to fit more snugly than other setting styles. Consider ordering a quarter to a half size larger with a wide band.

Where To Buy a Diamond Engagement Ring

Now that you have a plan for determining ring size, you can focus on finding the most stunning diamond ring at the best price. The first step is finding a reputable and reliable vendor who offers well-cut diamonds at excellent prices.

Throughout our years of experience in the diamond industry, we’ve vetted several diamond dealers. We have a consistent pulse on the companies you can trust.

Click Here To View More Details

For the best diamond cuts at an exceptional value, we recommend:

James Allen

  • Incredible diamond imagery
  • Focuses on customer experience
  • Appealing prices
  • High quality certification (GIA & AGS)

Blue Nile

  • Emphasizes remarkable diamond quality
  • Offers the largest online inventory of diamonds and settings
  • Known for beautiful jewelry settings
  • High quality certification (GIA & AGS).

Brian Gavin Diamonds

  • Offers only the best cut diamonds
  • Presents super-ideal cuts with the “Brian Gavin Signature” Hearts & Arrows collection
  • High quality certification (GIA & AGS)

How to Choose a Beautiful Diamond Ring

Our goal is for you to end up with the most exceptional diamond ring at an exceptional price. To achieve this, you need to keep in mind important components when assessing a diamond’s beauty and value. You want to spend in the areas that matter, and scale back in areas that’ll go unnoticed.

We recommend closely reviewing the diamond yourself or having a diamond expert assist you.

Be sure to follow our expert recommendations:

  • Certification: Ensure any diamond you’re considering has a GIA or AGS certificate.
  • Diamond Shape: Select a Diamond Shape that’s appealing to you. Shape is usually based on personal style.
  • Ring Setting: Do you want a vintage, halo or solitaire setting? Check out our engagement ring setting guide to determine the style that’s best for you.
  • Diamond Cut: Only consider diamonds with an ideal cut or an Excellent grade on the GIA scale. A well-cut diamond will maximize the brilliance and fire more than any other feature.
  • Diamond Clarity: Consider diamonds of VS1 and VS2 Clarity grade. These levels of clarity offer you the greatest value for what can be seen by the naked eye.
  • Diamond Color: Narrow your search to diamonds in the nearly colorless range of G-I. To the naked eye, these diamonds appear just as clear as those in the D-F range but cost significantly less.
  • Online Diamond Dealer: Select a diamond from a reputable diamond vendor with high-quality cuts and years of experience like Blue NileBrian Gavin Diamonds and James Allen.
  • Expert Assistance: Lean on the diamond experts. Ask for the complimentary help of an expert to review and search for high-quality diamonds. Check out resources like our 1 Carat and 2 Carat Buying Guides.

Reach out to us today to begin your complementary diamond search.

About the author
Mike learned the diamond business from the ground-up at Leo Schachter Diamonds - one of the world's top diamond manufacturers. He has been recognized as a diamond industry expert by Time, PeopleMoney, The Daily Mirror, NerdWallet, The Times Herald, Yahoo Finance Australia, The Art of Charm, The Washington Diplomat, The Next Web, and more. See more
Top Recommended Vendors
Blue Nile Blue Nile is the largest and most well known internet jewelry seller. They have a very large exclusive online inventory. Their high quality images are catching up to James Allens' and their prices are amazing. Blue Nile is currently running their biggest sale ever! (Click here for details)
What we love about them:
  • No questions asked returns within 30 days of shipment. Blue Nile will send you a paid shipping label to return the ring.
  • Lifetime Warranty
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  • Free prong tightening, repolishing, rhodium plating and cleaning every 6 months
  • Provide insurance appraisal
  • One free resizing within the first year of purchase
  • High quality images of about half of their diamonds
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James Allen James Allen is the leader in online diamond sales. Their imaging technology is the same as inspecting a diamond with a jeweler's loupe. They have the largest exclusive loose diamond inventory online and fantastic prices. They also have the nicest collection of lab created diamonds online.
What we love about them:
  • No questions asked returns within 30 days of shipment. James Allen will send you a paid shipping label to return the ring.
  • Lifetime Warranty
  • Free International Shipping
  • Free prong tightening, repolishing, rhodium plating and cleaning every 6 months
  • Provide insurance appraisals
  • One free resizing within 60 days of purchase
  • Free ring inscriptions
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  • 24/7 Customer Service
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