Ring Size Guide - Find Your Perfect Fit

Why Ring Size Matters

A well-fitted ring sits comfortably on your finger without slipping off or cutting off circulation. Getting your size right before ordering avoids resizing delays, and for intricate engagement ring settings, repeated resizing can risk the setting's integrity. Every Precious Carbon order includes a complimentary 90-day resizing guarantee, but the right size from the start means your ring is on your finger sooner.

How to Measure Your Ring Size at Home

Method 1: String or Paper Strip

This is the quickest method and works for most people.

What you need: A thin strip of paper or non-stretchy string, a pen, and a ruler.

Steps:

1. Cut a strip of paper approximately 6mm wide and 15cm long (or use a piece of string or dental floss).
2. Wrap it snugly around the base of the finger you plan to wear the ring on.
3. Mark exactly where the strip overlaps to complete a circle.
4. Lay the strip flat and measure from the end to your mark in millimeters - this is your finger's circumference.
5. Match your measurement to the ring size chart below.

Tip:

Measure in the afternoon or evening when your fingers are at their largest. Measure two to three times and take the average. If you're still unsure, contact our team, and we'll help you get it right before you order.

Method 2: Measure an Existing Ring

Best for accuracy, especially when buying a surprise gift.

What you need: A ring that already fits the intended finger, and a ruler or digital calipers.

Steps:

1. Choose a ring that fits the intended finger comfortably, ideally a plain band for the easiest measurement.

2. Measure the inner diameter of the ring in millimeters, from one inner edge straight across to the other. Do not measure the outer diameter.

3. Match your diameter to the chart below under the "Diameter (mm)" column to find your US, UK, and EU size.

Tip:

Digital calipers give the most precise reading and are available at most hardware stores for under $15. If you only have a ruler, measure twice and average the result.

Method 3: Printable Ring Sizer (Most Accurate)

The most reliable at-home method.

Steps:

1. Download our free printable ring sizer PDF. Open it in Adobe Reader or Preview, do not use "fit to page."

2. Print at exactly 100% scale. Verify accuracy by checking the printed measurement bar with a ruler - the 1-inch marker should measure exactly 25.4mm.

3. Place a ring you already wear over the printed circles. The circle whose printed edge aligns with the inner edge of your ring is your size.

4. Alternatively, cut out the paper sizer strip at the bottom, wrap it around your finger, and read your size where it overlaps the scale.

Ring Size Chart - US, UK, EU & Metric

Use your finger's circumference or diameter measurement to find your size. If you're shopping for a women's wedding band or a men's wedding band, cross-reference the same chart - the sizing standard is universal across all our rings.

Table	UK Size	EU Size	Diameter (mm)	Circumference (mm)
3	F	44	13.9	43.7
3.5	G	45.5	14.3	45.1
4	H	46.8	14.9	46.8
4.5	I	48	15.3	48.0
5	J–K	49.3	15.7	49.3
5.5	K–L	50.6	16.1	50.6
6	L	51.9	16.5	51.9
6.5	M	53.1	16.9	53.1
7	N	54.4	17.3	54.4
7.5	O	55.7	17.7	55.7
8	P	57	18.1	57.0
8.5	Q	58.3	18.5	58.3
9	R	59.5	18.9	59.5
9.5	S	60.8	19.4	60.8
10	T	62.1	19.8	62.1
10.5	U	63.4	20.2	63.4
11	V	64.6	20.6	64.6
11.5	W	65.9	21.0	65.9
12	X	67.2	21.4	67.2
12.5	Y	68.5	21.8	68.5
13	Z	69.7	22.2	69.7
14	Z+2	72.4	23.0	72.4

Most popular sizes

Note: If you fall between two sizes, size up by half. For bands 4mm or wider, including most men's wedding bands, go up half a size for a comfortable fit.

View Full International Ring Size Conversion Chart

Expert Tips for an Accurate Fit

Measure in the afternoon or evening.

Fingers swell throughout the day and are at their largest in the evening. Avoid measuring first thing in the morning.

Account for temperature.

Cold shrinks fingers; heat swells them. Measure at normal room temperature (68-72°F / 20-22°C) for the most reliable result.

Use the Correct Hand

Fingers swell throughout the day and are at their largest in the evening. Avoid measuring first thing in the morning.

Buying for a Surprise Proposal?

Borrow a ring your partner wears on their ring finger and measure its inner diameter. When unsure, order slightly larger - it's easier to size down than up, especially on engagement rings with side stones or halo settings.

Wider Bands Fit Tighter

If you're ordering a women's wedding band or men's wedding band that is 4mm or wider, go half a size up from your measured size. Slim solitaire settings typically don't require this adjustment.

Still Unsure?

Book a free virtual appointment with our diamond experts, and we’ll walk you through sizing at no obligation.

Book a free virtual appointment

Ring Size FAQs

What is the average ring size for women and men?

The average ring size for women in the US falls between 5 and 7, with size 6 being most common. For men, sizes typically range from 8 to 10.5, with size 9 as the average. Finger size varies significantly by height, weight, and genetics - always measure rather than assume.

What if my ring doesn't fit after delivery?

Every Precious Carbon order includes a complimentary 90-day resizing guarantee. If your ring doesn't fit on arrival, contact our team, and we'll arrange a free resize. Most resizing takes 5-7 business days. All our rings also carry a lifetime manufacturing warranty. Resizing may be limited for full eternity bands or very delicate metalwork - we'll advise at the time of order.

Can a ring be resized multiple times?

Yes, within practical limits. Sizing up or down by 1-2 sizes is generally safe. Excessive resizing can weaken the shank or affect prong integrity. Our jewellers will advise the safest approach for your specific ring's design and metal type.

How do I find my partner's ring size for a surprise proposal?

Borrow a ring they wear on their ring finger (left hand, fourth finger) and measure the inner diameter. Alternatively, press the ring into a bar of soap and measure the impression. When guessing is unavoidable, order slightly larger - sizing down is easier than sizing up, especially on engagement rings with side stones. Our Engagement Ring Guide covers this in more detail, and you can also start a custom design where sizing support is included throughout the process.

Is my ring size the same on every finger?

No. Each finger on each hand can be a different size, and your dominant hand is typically slightly larger. Always measure the specific finger you plan to wear the ring on. If your knuckle is significantly wider than the base of your finger, size for the knuckle and use a ring adjuster to prevent spinning.

What if I'm between two sizes?

Size up by half a size for most styles. For a diamond engagement ring worn daily, a slightly looser fit is preferable over too tight - you need to be able to remove it easily. Our team can advise on size preference for specific settings based on their design and bandwidth.