Wide bands, between sizes and resizing: choosing the right ring size
Short answer: go up when unsure. Wider bands fit tighter, so size up for bands over about 4 mm,[1 · Oct 29, 2026] and pick the larger size when you are between two, because removing metal is easier than adding it.[2 · Oct 29, 2026]

Band width
- GIA says wide shanks need a slightly larger size, and wider bridal sets need special consideration.[2 · Oct 29, 2026]
- Brilliant Earth suggests at least a half size up for bands wider than 4 mm.[1 · Oct 29, 2026]
- Jewelers Mutual also recommends a size up for wider bands.[3 · Oct 29, 2026]
Between sizes
GIA, Jewelers Mutual and Brilliant Earth all suggest choosing the larger size.[1 2 3 · Oct 29, 2026] Many US retailers also sell quarter sizes; one quarter size is 0.8128 ÷ 4 = 0.203 mm of diameter by our arithmetic.[4 · Oct 29, 2026]
Rings that are hard to resize
GIA notes that pavé, channel-set and eternity rings are difficult to resize because stones run around the band.[2 · Oct 29, 2026] For those styles it is worth measuring carefully more than once before ordering.
Which hand and finger
Measure the exact finger you will wear the ring on. GIA says that for a right-handed person the left ring finger is typically about half a size smaller than the right.[2 · Oct 29, 2026]
Do men's and women's ring sizes differ?
The US scale is the same for everyone; only the finger size differs.[4 · Oct 29, 2026] Typical average sizes by gender: Unverified. We couldn't confirm a reliable source for this yet.
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Sources: 1. Brilliant Earth, How to measure ring size. 2. GIA 4Cs, How to determine ring size. 3. Jewelers Mutual, How to measure ring size. 4. Wikipedia, Ring size. Checked Oct 29, 2026.