How to Size a Ring at Home
Method 1: The String Method
To find your ring size at home, wrap a piece of string or dental floss around the base of your finger, mark where the ends overlap, then measure the length in millimetres. Compare that measurement to the UK ring size chart below. This takes about two minutes and gives a reliable estimate for most finger shapes.
What You Need
- A piece of string, thread, or dental floss (about 15cm long)
- A pen or marker
- A ruler with millimetre markings
Step-by-Step
- Cut a piece of string approximately 15cm long
- Wrap it snugly around the base of the finger you want to measure — not too tight, not too loose
- If the ring will need to pass over your knuckle, measure around the knuckle as well and use the average of the two measurements
- Mark the point where the string overlaps with a pen
- Lay the string flat against a ruler and measure the distance between the marks in millimetres
- This measurement is your finger’s circumference — find it in the chart below to determine your UK ring size
Pro Tip
- Measure three times and take the average for the most accurate result
- Use non-stretchy string — elastic or stretchy cord will give an incorrect measurement
Method 2: The Paper Strip Method
This is a more precise version of the string method that uses a strip of paper instead.
- Cut a narrow strip of paper (about 1cm wide and 10cm long)
- Wrap the paper strip around the base of your finger
- Mark where the paper overlaps with a pen — mark the inside edge where it meets the paper end
- Lay the strip flat and measure from the end to the mark in millimetres
- Match the circumference measurement to the UK size chart below
Why Paper Is Better Than String
Paper does not stretch or bunch, making it slightly more reliable than string for an accurate circumference measurement. Use a strip from standard printer paper or a sticky note.
Method 3: The Existing Ring Method
If you already own a ring that fits the correct finger well, this is the most accurate home method.
- Place the ring on a flat surface
- Using a ruler with millimetre markings, measure the internal diameter of the ring — the distance from one inside edge to the other, across the widest point
- Match this diameter measurement to the chart below
Measuring Tips
- Measure the internal diameter, not the external — the ring’s metal thickness will skew the measurement if you measure outside
- Choose a ring that fits comfortably on the same finger you are sizing for — finger sizes differ between hands and between fingers
- If the ring is an unusual shape (e.g., oval or shaped band), measure the widest internal point
Full UK Ring Size Chart
The UK uses an alphabetical sizing system from A to Z+. Here is the complete chart with the corresponding internal circumference (in mm), internal diameter (in mm), and US size equivalent.
| UK Size | Circumference (mm) | Diameter (mm) | US Size |
|---|---|---|---|
| A | 37.8 | 12.0 | ½ |
| B | 39.1 | 12.4 | 1 |
| C | 40.0 | 12.7 | 1½ |
| D | 40.8 | 13.0 | 2 |
| E | 41.7 | 13.3 | 2¼ |
| F | 42.5 | 13.5 | 2½ |
| G | 43.4 | 13.8 | 3 |
| H | 44.2 | 14.1 | 3½ |
| I | 44.8 | 14.3 | 4 |
| J | 45.5 | 14.5 | 4½ |
| K | 46.3 | 14.7 | 5 |
| L | 47.1 | 15.0 | 5½ |
| M | 47.8 | 15.2 | 6 |
| N | 48.7 | 15.5 | 6½ |
| O | 49.5 | 15.7 | 7 |
| P | 50.3 | 16.0 | 7½ |
| Q | 51.2 | 16.3 | 8 |
| R | 51.9 | 16.5 | 8½ |
| S | 52.7 | 16.8 | 9 |
| T | 53.6 | 17.0 | 9½ |
| U | 54.4 | 17.3 | 10 |
| V | 55.3 | 17.6 | 10½ |
| W | 56.1 | 17.8 | 11 |
| X | 56.9 | 18.1 | 11½ |
| Y | 57.7 | 18.4 | 12 |
| Z | 58.6 | 18.6 | 12½ |
| Z+1 | 59.4 | 18.9 | 13 |
| Z+2 | 60.2 | 19.2 | 13½ |
| Z+3 | 61.0 | 19.4 | 14 |
Most Common UK Ring Sizes
- Women: L, M, N, O (most common: M)
- Men: R, S, T, U, V (most common: T)
- These are averages — always measure your own finger rather than guessing
Tips for Accuracy
Ring sizing is affected by several factors. Follow these tips to get the most accurate measurement possible at home:
Timing
- Measure at the end of the day — fingers swell slightly during the day due to activity and temperature
- Avoid measuring when cold — cold fingers shrink, leading to a ring size that is too small
- Avoid measuring after exercise or a hot shower — your fingers will be temporarily swollen
Width Matters
- Wider bands (6mm+) typically need to be half a size larger than narrow bands because they sit tighter on the finger
- If you are choosing a wide band ring, size up by half a size from your measured result
Knuckle Considerations
- If your knuckle is significantly larger than the base of your finger, measure both and choose a size between the two
- The ring needs to slide over the knuckle comfortably but sit snugly at the base without spinning freely
Dominant Hand
- Your dominant hand is usually slightly larger than your non-dominant hand — always measure the specific finger and hand the ring will be worn on
The Comfort Test
A correctly sized ring should slide on over the knuckle with slight resistance, sit snugly at the base of the finger without being tight, and come off with a gentle pull without flying off. If you are between sizes, choose the larger size — a ring that is slightly loose is more comfortable than one that is too tight.
When to Visit a Jeweller
Home measurements give a good estimate, but professional sizing is always more accurate. Visit OD’s Jewellers for a free, professional ring sizing if:
- You are buying an engagement ring or wedding band — these are significant purchases where accurate sizing matters most
- You are ordering an expensive ring that cannot easily be exchanged or resized
- Your knuckle is significantly larger than the base of your finger
- You have never had your finger professionally measured
- You are buying a ring as a surprise gift and need to be certain of the size
At OD’s Jewellers, we use professional ring sizing mandrels and gauge sets to measure your exact size. It takes less than a minute and there is no charge — just pop into the shop. We can also advise on which size to choose for specific ring styles and widths.
Rings from Brands We Stock
Frequently Asked Questions
How can I measure my ring size at home without a ring sizer?
Wrap a piece of non-stretchy string or a strip of paper around the base of your finger, mark where it overlaps, and measure the length in millimetres. This gives you the circumference. Match it to the UK ring size chart — for example, 47.8mm is a size M, which is the most common women’s size in the UK.
What is the most common ring size for women in the UK?
The most common women’s ring size in the UK is M, with sizes L through O covering the vast majority. This corresponds to a circumference of approximately 47–50mm or an internal diameter of 15–16mm.
What is the most common ring size for men in the UK?
The most common men’s ring size in the UK is T, with sizes R through V covering most men. This corresponds to a circumference of approximately 52–55mm or an internal diameter of 16.5–17.5mm.
Should I size up or down if I am between ring sizes?
Size up. A ring that is slightly loose is more comfortable and safer than one that is too tight. A tight ring can restrict blood flow and become difficult to remove, especially in warm weather when fingers swell.
Does ring size change over time?
Yes. Finger size can change due to weight fluctuation, temperature, pregnancy, age, and even time of day. Most people find their ring size fluctuates by about half a size depending on conditions. It is worth being re-measured every few years.
Can OD’s Jewellers resize a ring?
We offer a free professional ring sizing service in-store. For resizing an existing ring, we can advise on whether the piece is suitable for resizing and connect you with a specialist. Some ring designs (particularly wide bands or rings with continuous stone settings) cannot be easily resized.