If you already have a ring that fits you well, using a metal ring sizer stick (often called a ring sizing mandrel) is one of the most precise and reliable ways to determine your exact ring size. Recognized by ISO 8653:2016 as the official method for professional ring measurement, it ensures accurate sizing across standard international systems.
Which ring sizer should I buy?
This is our selection of two top-quality metal ring size sticks to help you find the perfect fit with maximum precision.
Ring Sizer Stick (UK, US, EU)
- Displays US sizes 2 to 16.
- Multistandard references: UK, EU, and circumference.
- Made from lightweight, durable aluminum.
- Includes half sizes for added accuracy.
Ring Sizer Stick (US) + Gauge
- Displays sizes 0 to 13 in the US system.
- Includes a ring size gauge.
- Includes half sizes for added accuracy.
- Made from lightweight, durable aluminum.
How to use a ring sizer stick
We follow the exact steps defined by the ISO 8653:2016 standard, the official method used by professionals worldwide to measure ring sizes with a metal sizer stick.
Time:
1 minute
Tools:
Reference ring, Ring size stick
Step 1: Insert the ring
Let the reference ring slide down the sizer stick until it stops and rests snugly at the point where it no longer moves. Make sure it sits flat and aligns with the markings for an accurate reading.
Step 2: Read the size
Read the mark next to your ring in your preferred sizing system. For better accuracy, use either the center or bottom reading depending on the ring’s thickness and inner shape.
Center or bottom reading: How to accurately read a ring sizer stick
Bottom edge for flat rings, center mark for comfort rings
The ISO 8653:2016 standard also explains how to read the ring size depending on the interior shape of the band. Rings with a flat interior sit evenly against the sizing stick, making the bottom edge (B) the correct reference point. In contrast, comfort fit rings are curved on the inside and don’t make full contact with the stick. In those cases, reading the size from the center (A) of the ring provides a more accurate result.
Bottom edge for narrow rings, center mark for wide bands
Jewelers recommend adjusting the reading method based on the width of the ring. Narrow rings, like engagement rings, are best read from the bottom edge (A). Wide bands, like many men’s rings or bold designs, rest more fully against the finger, so the size should be taken from the center (B) to reflect the true fit.
Convert your ring size to another system
If you want to check your size in additional systems not marked on your ring sizer stick, use our conversion chart to find the exact match.
View conversion ring size chart
Other Frequently Asked Questions using and reading a ring sizer stick
To measure a signet ring or any ring with a large top, place it on the ring stick with its flat base resting against the flat side of the sizer stick. This ensures the ring is properly aligned, as specified in ISO 8653:2016. The size is then read based on the shape of the interior: at the bottom edge if the inside is flat, or at the center if it has a comfort fit.
No. Although some people refer to it as a “ring mandrel”, a ring sizer stick is meant only for measuring, not for resizing or reshaping rings. Jewelers use forming mandrels, which are solid metal tools designed for adjusting the shape of a ring. Trying to stretch or reshape a ring using a sizing stick can damage both the ring and the tool.
The ISO 8653:2016 standard also includes guidelines for rings with unconventional shapes.
For rings made of multiple interlaced circles, the size is read from the bottom edge of the ring, as if it had a flat interior.
For square rings, the band should be positioned so that a circle can be inscribed within the square, avoiding alignment between the ring’s flat sides and those of the stick. The measurement point then depends on the inner profile of the ring (bottom edge for flat interiors, center point for comfort fit).
Plastic sizer sticks can be helpful for basic use, but they are less accurate and durable than metal ones. If you are planning to buy one, a calibrated metal ring stick is the best option. It offers better precision, lasts longer, and meets the requirements of ISO 8653:2016, the international standard that defines ring sizes using measurements taken from a cylindrical metal stick with strict tolerances. That’s why calibrated metal sticks are the standard in professional workshops.
Most official ring sizer sticks include engraved markings in at least one of the major systems, such as US, UK, or EU. If you need to convert that measurement to other international standards, you can use our ring size conversion chart. It helps you find the equivalent size across different systems quickly and accurately.
Alternative free methods to determine the size of a ring at home
Printable ring size chart
Print a free chart with ring size references and place your ring over the printed circles to quickly identify its exact size.
On-screen ring sizer
Place your ring directly on the screen after calibration and instantly find its size. Works on phones, tablets, or computers.
Measure a reference ring
Measure the inner diameter of a ring you already own with a ruler and convert it to your correct size using our calculator.
Feedback from people following our ring size stick guide