How do I measure my ring size at home?

Wrap a string or paper strip around the base of your finger, mark where it overlaps, then measure the length in millimeters. Divide by 3.14 to get the diameter. Alternatively, measure the inside diameter of a ring that fits well. For accuracy, measure at the end of the day when fingers are largest, and measure 3-4 times.

What is the difference between US and UK ring sizes?

US and UK ring sizing systems use different scales. US sizes run from approximately 3 to 13, while UK sizes use letters (A to Z) and half sizes. A US size 7 is approximately UK size N or O. The conversion is not exact because the systems evolved independently.

Can ring size change over time?

Yes, ring size can change due to weight fluctuations, pregnancy, temperature, time of day, and aging. Fingers are typically smaller in the morning and larger in the evening. Weight gain/loss of 10+ pounds can change ring size by 0.5 to 1 full size. It's wise to size rings in the afternoon and account for seasonal temperature changes.

Biggest Calculator Hub

Unit ConversionsVerifiedFeb 2026

Ring Size Converter

Name: Ring Size Converter
Author: Biggest Calculator Hub

Convert ring sizes between US, UK, European sizing systems and ring diameter in millimeters. Essential tool for international jewelry purchases and custom ring orders.

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How to Use the Ring Size Converter

This free ring size converter helps you quickly calculate us size. Simply enter your values in the fields above and click "Calculate" to see your results instantly.

Understanding Your Results

After entering your information, the calculator will display your results including us size, uk size, eu size, diameter (mm), circumference (mm). Each result is calculated using standard formulas used by financial professionals and experts in the field.

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