How to Measure Ring Size at Home

Getting the ring size right is crucial for a perfect proposal. While professional sizing at a jeweller is most accurate, there are several reliable methods to determine ring size at home—even if you're planning a surprise proposal. This guide covers everything you need to know about Australian ring sizing, from measurement techniques to accounting for temperature changes.

Understanding Australian Ring Sizes

Australia uses a letter-based sizing system that runs from approximately A (smallest) to Z+ (largest). This differs from the US numerical system and European millimetre-based measurements. Most Australian women wear sizes between J and P, with M being roughly average.

The letter corresponds to the internal circumference of the ring. Each size increment represents approximately 1.25mm in circumference. Knowing this helps when you're between sizes—it's generally better to go slightly larger, as rings can be sized down more easily than up.

Method 1: Measure an Existing Ring

If your partner already wears a ring on their left ring finger, this is the most reliable method. The key is borrowing a ring they wear on the correct finger—rings worn on different fingers will give inaccurate results.

To measure the ring:

• Place the ring on a ruler and measure the internal diameter in millimetres
• Use a ring size chart to convert the diameter to an Australian size
• Alternatively, trace the inside of the ring on paper and take this to a jeweller

Be sneaky about borrowing the ring—take it while they're showering or sleeping, measure quickly, and return it before it's missed. Some partners enlist friends or family to help "borrow" a ring for sizing.

Method 2: The String or Paper Method

If measuring their finger directly isn't possible, this method works with any ring they own:

1. Cut a thin strip of paper or use non-stretchy string
2. Wrap it around the inside of their existing ring
3. Mark where the paper/string meets itself
4. Measure this length in millimetres—this is the circumference
5. Divide by 3.14 to get the diameter, then use a size chart

Method 3: Direct Finger Measurement

If you can measure their finger directly (perhaps while they're sleeping, or with their cooperation for a "different" ring), wrap a strip of paper snugly around the base of their left ring finger. Mark where the paper overlaps and measure the length.

Factors That Affect Ring Size

Temperature

Fingers swell in heat and shrink in cold. In Australia's warm climate, consider that fingers measured in summer will be slightly larger than in winter. Measure at room temperature for the most accurate result, and consider going up a quarter size if you're proposing during summer.

Time of Day

Fingers are typically smallest in the morning and swell slightly throughout the day due to activity and gravity. Evening measurements tend to be most representative of normal wear.

Exercise and Salt Intake

Fingers swell after exercise and when consuming salty foods. Avoid measuring right after a workout or a particularly salty meal.

Secret Sizing Strategies

Planning a surprise proposal adds complexity to sizing. Here are proven strategies:

• Enlist family or friends: A mother, sister, or best friend may already know the size or can help discover it naturally
• Use a silicone ring sizer: These affordable tools can be "accidentally" left around for them to try
• Browse rings together: Many couples shop together these days. Suggest trying on "fun" rings at markets or costume jewellery stores
• Compare to your own fingers: When holding hands, mentally note which of your fingers matches theirs

What If You Get It Wrong?

Don't panic—most jewellers offer complimentary resizing within a reasonable range (typically 2-3 sizes up or down). When purchasing, confirm the resizing policy. Some ring styles, particularly those with stones set around the entire band (eternity styles), are more difficult to resize and may require purchasing a new ring.

Remember that the moment matters more than perfect sizing. Many couples cherish the resizing trip as part of their engagement story—an opportunity to visit the jeweller together and ensure the ring fits perfectly for a lifetime of wear.