Fit guide

Ring Size Guide

Every diamondboi ring is made to your size. Here are three reliable ways to find it, what to do if you are buying a surprise, and what happens if the fit is not perfect.

Find your size

Inside diameter of a ring that fits that finger

Measure edge to edge across the inside of the band, not including the metal. A ruler works; a caliper is better.

Measuring well

Measure at the end of the day. Fingers are smallest first thing in the morning and when cold. Room temperature, late afternoon or evening gives the truest reading.
Account for the knuckle. The ring has to pass over it. If the knuckle is noticeably larger than the base of the finger, choose a size between the two.
Measure three times. Take the most common result, not the first. A half size is less than half a millimetre of diameter, so small errors matter.
Wider bands wear tighter. For bands 6 mm and wider, or eternity styles, go up about a half size from a thin-band measurement.
When in doubt, go slightly larger. Taking a ring in is simpler than letting it out, and one complimentary sizing is included with every diamondboi ring (eternity bands excepted, since diamonds run all the way around).

Size chart

US and Canadian sizes with inside diameter and circumference in millimetres, plus approximate UK and EU equivalents. Every diamondboi ring is made to your size, including quarter sizes on request.

US / CA	Diameter	Circumference	UK / AU	EU / ISO

Sizing a surprise

Most engagement rings are bought without the wearer knowing. These are the methods that work most reliably, in order.

Borrow a ring she already wears

It must be one worn on the ring finger of the left hand, or the same finger on the right (sizes differ between hands). Measure its inside diameter and use the calculator above, or bring it to the studio.

Trace it

If you can only borrow it for a minute, press it into a bar of soap or trace the inside circle on paper several times, then measure the clearest tracing.

Recruit an ally

A sister, mother or close friend can often find out directly, or already knows. Jewellers she has shopped with may have her size on file.

Order the most likely size

If you are between two, choose the larger. The most common women's ring sizes are 6 to 7, but hands vary widely; a photo of her hand next to a common object helps us estimate.

Still not sure?

Tell us what you know in the order notes and we will confirm the size with you before casting. You can also text us a photo, or stop by the studio to be measured properly.

Book a consultation Text (647) 972-7464