Ring sizing is the step most buyers underestimate and most commonly get wrong. An accurate ring size before ordering means the ring fits the day it arrives. This guide gives you five methods to find your size accurately at home, with no tools you don’t already own.
Why Ring Size Matters More Than You Think
A ring that is too small cannot be put on. A ring that is too large will fall off. A ring one half-size off will be uncomfortable over months of daily wear. Moissanite rings in solid gold can be resized, but the process costs money, takes time, and is not always possible for all settings (eternity bands, channel-set rings, and heavily pavé-set bands have limitations). Getting the size right before ordering is always preferable. See our resizing guide.
Method 1: The String or Paper Strip Method
The most accurate home method. Cut a thin strip of paper (approximately 6mm wide and 10cm long). Wrap it snugly around the base of the finger you will wear the ring on — snug enough to feel resistance, but not so tight it cuts off circulation. Mark where the end meets the strip. Measure the length from the start to your mark in millimeters. This is your finger circumference. Use the chart below to convert to a US ring size. Important: measure at the end of the day, when fingers are at their largest. Measure twice and take the average.
Method 2: Measure an Existing Ring
If you already own a ring that fits well on the target finger, measure its internal diameter: place the ring on a ruler and measure straight across the inside of the band in millimeters. Use the diameter column in the chart below to find your US size. This is the fastest method when an existing fitting ring is available.
Method 3: Printable Ring Sizer
Print a ring sizer at 100% scale (do not scale to fit page — this will change the measurements). Place your existing ring over the printed circles until you find the one that matches the inside of your band. Alternatively, cut out the strip and wrap it around your finger. Available on most major ring retailer websites and at Moissanite Shine upon request.
Method 4: Plastic Ring Sizer Tool
A plastic ring sizer — a loop of connected size tabs — is available from any jewelry supply or Amazon for under $5. It is the most reliable non-professional method: try each size on the target finger until you find the one that slides on with slight resistance and sits at the base without sliding off. Size up if you are between sizes (see below).
Method 5: Visit a Local Jeweler
Any jewelry store will measure your ring size for free in under a minute using a professional mandrel and ring gauge set. This is the most accurate method. There is no obligation to purchase. If you are buying a significant piece — an engagement ring, a wedding band — this is the recommended approach.
US Ring Size Chart
Size 4: Circumference 46.8mm / Diameter 14.9mm
Size 4.5: Circumference 48.0mm / Diameter 15.3mm
Size 5: Circumference 49.3mm / Diameter 15.7mm
Size 5.5: Circumference 50.6mm / Diameter 16.1mm
Size 6: Circumference 51.9mm / Diameter 16.5mm
Size 6.5: Circumference 53.1mm / Diameter 16.9mm
Size 7: Circumference 54.4mm / Diameter 17.3mm
Size 7.5: Circumference 55.7mm / Diameter 17.7mm
Size 8: Circumference 57.0mm / Diameter 18.1mm
Size 8.5: Circumference 58.3mm / Diameter 18.6mm
Size 9: Circumference 59.5mm / Diameter 18.9mm
Size 9.5: Circumference 60.8mm / Diameter 19.4mm
Size 10: Circumference 62.1mm / Diameter 19.8mm
Between Sizes: Which Way to Go?
If you measure between two sizes, size up for: wide bands (3mm+), rings with a heavy pavé band, and anyone whose knuckles are significantly larger than the base of their finger. Size down for: slim bands (under 2mm) and anyone whose knuckle and finger base are similar in size. When in doubt on an engagement ring: size up. A ring that is slightly large can be temporarily sized with a ring adjuster insert; a ring that is too small cannot be worn at all.
Common Sizing Mistakes
❌ Measuring in the morning when fingers are at their smallest.
❌ Measuring when cold (fingers shrink in cold).
❌ Pulling the string too tight.
❌ Using a wide band and ordering the size that fits a narrow band.
❌ Ordering an engagement ring size and assuming it matches a wide wedding band size.
Sizing for Someone Else
If ordering a surprise ring: borrow a ring she wears on the target finger and measure its internal diameter (Method 2). If no ring is available, see our ring size secret guide. All Moissanite Shine rings can be exchanged for a different size within 30 days. See our returns page.
Shop Moissanite Rings
Engagement Rings · Wedding Bands · Custom Design. DEF, VVS1, GRA certified, solid gold, lifetime warranty.