What you actually need to size a ring at home
You can size a ring at home with very little. The goal is a number you can trust before you spend money on a ring that cannot be resized. Here is what each tool does, what to look for and when a cheaper option is enough.
Finger gauge set
A set of rigid, numbered rings in half sizes lets you try each size on the finger. Look for a set that covers half sizes and, if you plan to wear a wide band, includes wide-band gauges. Try the gauge on the right finger and hand, at the end of the day, and note which size passes the knuckle with slight resistance. This is the closest match to being sized at a jeweller.
Digital calliper
A calliper measures the inside diameter of a ring that already fits to a tenth of a millimetre. It is the best way to read the size of an existing ring. Measure twice after rotating the ring. A cheap plastic or steel calliper is fine for this job. See how to measure an existing ring.
Ring mandrel
A tapered metal rod with size markings, used to read a ring's size by sliding it on until it stops. It is useful if you have several rings to check or if the ring may be oval. For one ring, a calliper is enough.
Printable sizer and paper strip
Free, and good for an estimate. Print at 100 percent and verify the scale with the 50 mm check line on our printable sizer. Paper and string can give the wrong size, so use them to narrow the range, not to order a non-resizable ring.
What to skip
Skip any tool that does not state its scale (US, UK or EU) and skip single-size gauges. Skip sizers that claim to fit "any finger" with no half sizes. A jeweller's visit costs little and beats a guess.
Next step
Use the calculator to turn your measurement into a size, then read the full measuring guide. See all our free tools.