Choosing the perfect ring is a special moment—whether it’s an engagement, a gift, or simply a treat for yourself. But before you hit “add to cart,” there’s one crucial detail you need to get right: your ring size.
In this guide, you’ll learn simple and reliable ways to determine your ring size from the comfort of your own home—no professional jeweler needed.
Why Accurate Ring Sizing Matters
Wearing a ring that’s too loose puts you at risk of losing it, while a ring that’s too tight is uncomfortable and hard to remove. Especially for custom lab diamond jewelry, getting the size right the first time helps you avoid expensive resizing or returns.
1. Use a Printable Ring Sizer
One of the easiest methods is to use a printable ring sizer:
How it works:
Download and print a ring size guide (many jewelers offer these).
Cut out the ring sizer and wrap it around your finger.
Align the arrow or line with the right size marking.
Tip: Make sure the guide is printed at 100% scale. Use a credit card or ruler on the printout to confirm accuracy.
2. Measure an Existing Ring
If you already have a ring that fits the desired finger, use it as a guide.
Steps:
Find a millimeter ruler.
Measure the inside diameter of the ring (across the center).
Compare that measurement to a standard ring size chart.
Inside Diameter (mm)
US Ring Size
16.5
6
17.3
7
18.1
8
19.0
9
3. The String or Paper Strip Method
This old-school DIY trick is surprisingly effective.
What you need:
A piece of string or a thin strip of paper
A pen
A ruler (mm)
Steps:
Wrap the string around the base of your finger.
Mark the point where the ends meet.
Measure the length with a ruler.
Use a size chart to match the circumference to a ring size.
Circumference (mm)
US Ring Size
52.4
6
54.4
7
57.0
8
59.5
9
4. Order a Ring Sizer Tool Online
If you want to be 100% sure (especially for an expensive piece like an engagement ring), you can order a plastic ring sizer online. These tools are inexpensive and often reusable.
They look like a zip tie or a ring of multiple sizer rings and give you a precise reading.
5. Consider Time and Temperature
Finger size can fluctuate due to:
Time of day (larger in the evening)
Weather (heat causes fingers to swell)
Activity (hydration, physical effort)
Best time to measure: Late afternoon or evening, at room temperature, when your body is relaxed.
What If You’re Gifting a Ring?
Surprise gifts add a layer of difficulty. Here are some stealthy tricks:
Borrow one of their rings (from the correct finger).
Ask their friend or family member.
Use a ring they wear on a similar-sized finger (like the opposite hand’s ring finger).
Bonus: Resizing Policy & Lab-Grown Jewelry
If you’re investing in a lab-grown diamond engagement ring, check if the jeweler offers free resizing. Some designs (especially full eternity bands) are hard to resize after production.
💡 At Tidew, many of our lab-grown diamond rings are customizable with size options upfront—making it easier to order confidently.
Final Thoughts
Finding your ring size at home is easier than you think. Whether you go the DIY route or buy a ring sizer, the key is to measure carefully and double-check.
Once you know your perfect size, you’re ready to shop with confidence—especially for that custom lab diamond jewelry you’ve been eyeing.
