Ring Sizing Guide: How to Measure Your Ring Size at Home

Hand wearing a gold ring beside a ribbon, illustrating how to measure ring size at home

Buying a ring online is exciting until you get to the size dropdown and freeze. The good news is that you can figure out your ring size at home in about five minutes using tools you probably already have: a strip of paper, a ruler, or an existing ring you already wear. Below we walk through the most reliable at home methods, share a US to UK to EU size conversion chart, and cover the small details (like time of day) that can throw your measurement off by a full size.

Key Takeaways

The paper or string method is the most accessible way to measure ring size at home: wrap it around your finger, mark the overlap, and measure in millimeters.
Each whole US ring size equals about 0.8mm of inside diameter, or roughly 2.5mm of circumference.
Measure in the mid afternoon or evening, since fingers are naturally smaller in the morning and can swell later in the day or in warm weather.
If you already own a ring that fits the intended finger, measuring its inside diameter is usually more accurate than measuring the finger itself.
US, UK, and EU ring sizes all use different scales. Always convert using millimeters, the one measurement that stays consistent across every system.

On this page

The String and Paper Method
Printable and Reusable Ring Sizers
US, UK, and EU Ring Size Chart
Measuring a Ring You Already Own
Tips for an Accurate Measurement
Shop Adjustable Size Ring Sets
FAQ

The String and Paper Method

This is the simplest way to measure ring size without any special tools. Cut a thin strip of paper (or use a piece of non stretchy string) about 6 inches long and roughly a quarter inch wide, along with a pen and a millimeter ruler.

Wrap the strip snugly around the base of the finger you plan to wear the ring on. Snug is the goal, not tight enough to pinch and not loose enough to slide off.
Mark the exact point where the strip overlaps itself with a pen.
Lay the strip flat against your millimeter ruler and measure from the starting end to your mark. That number is your finger's circumference in millimeters.
Compare that circumference to the chart below to find your closest US, UK, or EU size.

Hands wrapping a paper strip around a finger to measure ring size using the string method

Wrap the strip snugly, mark the overlap, then measure the length against a ruler in millimeters.

Printable and Reusable Ring Sizers

If you would rather not do the math yourself, a few tools make this even easier:

Printable ring sizer charts. Many jewelers offer a free printable PDF with sizing circles or a paper strip built in. The most important step is printing it at actual size. Always choose "Actual Size" or "Scale 100%" in your print settings, since browsers and PDF readers sometimes shrink pages by default and will throw off every measurement.
Plastic ring sizer gauges. These small reusable discs have a set of graduated holes, each corresponding to a specific ring size. Slide your finger through the holes until you find the one that fits snugly, and read off the size.
Ring mandrels. A tapered metal or plastic rod used by jewelers to size an existing ring, useful if you want to measure a ring rather than a finger.

Hand holding a plastic ring sizer gauge tool to check ring size

A reusable plastic ring sizer gauge gives a quick, repeatable reading without any math.

US, UK, and EU Ring Size Chart

Ring sizing systems vary by country. US and Canadian sizes use whole and half numbers (like 6 or 6.5), UK and Australian sizes use letters (like J or K), and most of Europe uses a number tied directly to the inside circumference in millimeters. Millimeters are the one measurement that is universal, so when in doubt, ask for the mm measurement rather than a letter or number.

US Size	Diameter (mm)	Circumference (mm)	UK Size
4	14.8	46.5	H
5	15.7	49.3	J
6	16.5	51.9	L
7	17.3	54.4	N
8	18.1	56.9	P
9	18.9	59.5	R½
10	19.8	62.1	T½

Figures are standard reference measurements rounded to the nearest tenth of a millimeter. Wide band styles typically fit slightly snugger than thin bands, so sizing up a quarter to half size is common advice for statement rings and wide bands.

Measuring a Ring You Already Own

If you already own a ring that fits the intended finger comfortably, measuring the ring itself is often more accurate than measuring the finger, since fingers can be affected by temperature and swelling while a ring's inside diameter never changes. Lay the ring down flat, measure straight across the inside from edge to edge in millimeters, and compare that diameter to the chart above. A local jeweler can also confirm the size for free in under a minute using a mandrel.

Five gold rings of ascending sizes lined up to show how ring sizes differ

Even a small size difference changes a ring's inside diameter by less than a millimeter, which is why precise measuring matters.

Tips for an Accurate Measurement

Measure in the afternoon or evening. Fingers tend to run smaller in the morning and expand later in the day, so an afternoon measurement is usually the most representative.
Avoid measuring right after exercise, in the heat, or when your hands are cold. Temperature and activity both cause temporary swelling or shrinking.
Measure two or three times and average the results. A single reading can be off by a quarter size.
Account for knuckle size. If your knuckle is noticeably larger than the base of your finger, size for comfortable movement over the knuckle rather than just a snug fit at the base.
Consider the band width. Wider bands (6mm and up) generally need to be sized slightly larger than thin bands to feel the same on the finger.

Shop Adjustable Size Ring Sets

Once you know your number, these sterling silver jewelry sets are available across a range of standard US sizes, so you can shop with confidence: