How to Measure Your Ring Size at Home — Complete Guide

By Dmitry Strugovshchikov, founder of STRUGA

Ordering a ring online, and the biggest fear is getting the wrong size. Here are three proven methods to measure your ring size at home — no jeweler visit required.

Method 1: The String Method

The most popular DIY method. You'll need a piece of string or thin strip of paper, a ruler, and our size chart.

1. Wrap the string snugly around the base of your finger.
2. Mark where the string overlaps.
3. Measure the length in millimeters.
4. Compare with the chart below.

Pro tip: Measure at the end of the day when fingers are slightly larger, and cold weather shrinks fingers by up to half a size.

Method 2: Existing Ring Comparison

If you already own a ring that fits, place it on a ruler and measure the inner diameter in millimeters.

Inner Diameter (mm)	US Size	EU Size	RU Size
15.7	5	49	15.5
16.5	6	52	16.5
17.3	7	54	17
18.2	8	57	18
19.0	9	59	19
19.8	10	62	20
20.6	11	64	20.5
21.4	12	67	21.5

Method 3: Printable Ring Sizer

Download and print our ring sizer PDF (make sure to print at 100% scale). Place your existing ring over the circles to find your match.

STRUGA Ring Sizing

All STRUGA rings are available in US sizes 5-13, and wide bands (8mm+) like our Blade collection may feel tighter — we recommend ordering half a size up.

For the Dark Union wedding rings, we offer complimentary resizing within 30 days of purchase.

International Size Conversion

The RU system is based on inner circumference in millimeters, and Europe also uses circumference, but with different numbers. The US system is unique, and our product pages show all three systems for every ring.

Still unsure? Contact us — we'll help you find the perfect fit.

The four reliable methods

Sizing a ring at home is straightforward if you use one of the four reliable methods. Each has different precision; pick based on what tools you have available.

Method 1 — string and ruler

1. Wrap a string or paper strip around the base of the finger you want to size.
2. Mark where the string overlaps with a pen.
3. Measure the marked length in millimeters.
4. Divide by π (3.14) — this gives the inside diameter in mm.
5. Match to a ring size chart.

Precision: ±0.5 ring size. Good for a first estimate.

Method 2 — existing ring trace

1. Find a ring you already wear comfortably on the same finger.
2. Place it on paper. Trace the inside circle carefully.
3. Measure the diameter of the inside circle in mm.
4. Match to a ring size chart.

Precision: ±0.25 ring size. Most reliable home method.

Method 3 — printable ring sizer

1. Download a printable ring sizing sheet from a reputable source. Print at 100% scale (verify with the included calibration line).
2. Cut out the sizer strip.
3. Wrap around the finger, slide through the slot.
4. Read the number where the slot lines up.

Precision: ±0.5 ring size depending on print accuracy.

Method 4 — physical ring sizer (mandrel + sizer set)

1. Use a steel ring sizer set — a series of rings in 0.25-size increments.
2. Try each size on the finger; identify the size that fits comfortably.
3. This is the size to order.

Precision: most accurate. Available from jewelry supply retailers for $10–$30.

Common sizing mistakes

• Sizing in the morning vs. evening. Fingers swell during the day. Size in the late afternoon or early evening when the hand is at typical wearing temperature and humidity.
• Sizing right after exercise or hot weather. Heat and exercise temporarily swell fingers. Wait until the hand returns to baseline.
• Forgetting knuckle size. A ring needs to slide over the knuckle to reach the base of the finger. If the knuckle is significantly larger than the base, size up by 0.5–1 size and use a sizing bead inside the band to keep the ring secure at the base.
• Sizing one finger and applying to another. Each finger has its own size. The ring finger and middle finger of the same hand often differ by 0.5–1 size.
• Ignoring band width. Wider rings (6mm+) fit tighter than thin bands at the same numerical size. For wide rings, size up by 0.25–0.5.

Ring size charts — quick reference

US Size	UK Size	EU Size	Inside diameter (mm)
5	J½	49	15.7
6	L½	52	16.5
7	N½	54	17.3
8	P½	57	18.1
9	R½	59	18.9
10	T½	62	19.8
11	V½	64	20.6
12	X½	67	21.4

Conversion is approximate. Always confirm against the seller's specific chart.

How to size for a surprise gift

1. Borrow an existing ring. If they wear one regularly, take it overnight and trace the inside circle. Use the diameter for sizing.
2. Measure indirectly. A ring traced onto paper while they're not looking. Measure the inside circle on the trace.
3. Buy a non-ring piece. If sizing is too risky, choose a pendant or bracelet that doesn't need sizing.
4. Buy adjustable. Some ring designs allow ±2 size adjustment built in. Limited aesthetic options but solves the sizing question.
5. Get a gift receipt. Plan for the recipient to bring the ring back for resizing if it doesn't fit.

Frequently asked questions

What size should I order if I'm between two sizes?

Order the larger size and have it sized down if needed. Sizing down is structurally easier than sizing up on most ring designs. Wide bands particularly should be ordered slightly larger.

Can ring size change over time?

Yes. Pregnancy, weight changes, age, and even temperature affect ring size. Most adults' size shifts ±1 size across decades. Re-measure periodically if a long-worn ring starts to feel different.

How do I size for a wide band differently?

Wide rings (6mm+) fit tighter than thin bands at the same numerical size. Order 0.25–0.5 sizes larger than your standard size for wide bands.

What if my knuckle is much bigger than my finger base?

Size to slide over the knuckle, then add a sizing bead or insert inside the band. The bead keeps the ring secure at the base. STRUGA can add this during production for a small extra fee.

Can STRUGA resize a ring after purchase?

Yes — most STRUGA rings can be resized by ±2 sizes through the workshop. Service is part of lifetime maintenance. Wide bands and stone-set rings have more constraints than plain bands.

How accurate are online sizing apps?

Variable. Best apps that use phone-camera measurement can get within 0.5 size; less reliable apps can be off by 1+ sizes. Verify with a physical method before ordering high-priced rings.

Should I size for the finger I plan to wear it on?

Yes. Each finger has its own size. The right hand and left hand of the same finger sometimes differ slightly. Size specifically for the planned wear position.