Screen measurement
Online Ring Sizer
Calibrate your screen, place a ring flat on the circle, and estimate the closest international ring size.
Step 1 of 3
Calibrate your screen
Place a credit card on the outline, then adjust until it matches.
Reference
Credit card width
Known size
85.60 mm
Screen scale
3.79 px/mm
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Standard credit card size is 85.60 mm x 53.98 mm. The card preview scales as one piece, then the ring circle uses the same screen ratio.
If the real card only matches near the high end, your browser zoom or display scaling is using smaller CSS pixels. That is fine after calibration. On many phones, a full credit card may not physically fit; use the ruler check or printable sizer instead.
Why calibration mattersTrust checklist
Before you trust the result
Screen measurement can be useful, but only when the calibration and the ring placement are both checked.
1. Calibrate the screen
Use a credit card width of 85.60 mm or the 50 mm ruler check. If your browser zoom or screen size changes, calibrate again.
2. Match the inner opening
Place the ring flat and align the circle to the inside edge. Do not include the metal band thickness.
3. Verify important purchases
Use the printable sizer or a jeweler for engagement rings, custom rings, or expensive purchases.
This tool provides an estimated ring size only. Double-check before buying, especially for expensive, custom, or engagement rings.
FAQ
Common questions
How accurate is this ring size tool?
It provides an estimated ring size. Screen calibration, browser zoom, ring alignment, and measuring method can all affect the result.
Can I measure ring size on my phone?
Yes. A phone is often easier because you can place a ring directly on the screen after calibration.
What if I am between two sizes?
Check the fit with another method. Wider bands can feel tighter, so many buyers choose the larger nearby size for wide rings.
Should I use this for an engagement ring?
Use it as a starting point only. For expensive, custom, or engagement rings, confirm with a professional jeweler.