True Ring Size: Sizer & Gauge

lapnito development studio

About this app

True Ring Size — Ring Sizer · Finger Sizer · Size Converter.
Place your ring here
Pinch here to resize the circle
Ring diameter. Increase by 0.05 mm. Decrease by 0.05 mm.
Diameter: 18.50 mm · Diameter: 0.728 in · Circumference: 18.50 mm · Circumference: 0.728 in.
Save size. Size saved.
Display Calibration
Place a credit card on the screen in portrait and resize the frame until it matches the card exactly.
Approximate — using an estimate from your display. Calibrate with a card for accuracy.
Calibrated · Measurement accuracy.
Pinch here to resize the frame. Drag with two fingers to resize the frame.
Fine adjustment. Save calibration.
Before you measure
A finger is soft and oval, so this method is approximate. Measure at the knuckle, measure twice, and if you have a ring that fits, verify with the Ring tab.
Lay your finger here, across the guides
Slide the guides to the edges of your finger at the knuckle — not the fingertip.
A finger is oval — for best accuracy verify with the Ring tab.
This ring is too large to measure on screen precisely — use the Finger tab instead.
Calibrate once
For real accuracy, match a bank card on screen once in Settings. You can measure right away without it — results are just approximate.
Measure a ring or finger
Lay a ring on the screen and resize the circle to fit, or slide the guides to your finger. Every size system updates live.
Save and convert
Save sizes for yourself and others, and convert instantly between US, UK, EU, JP, CN and RU.
Size Converter
System · Size.
Full size table
Search any size or mm
US · UK · EU · JP · CN · RU · mm · in.
No sizes match your search. Last saved.
Saved Sizes
Measure a ring or finger, or add a size you already know.
Ring method · Finger method · Entered manually.
Person · Hand · Finger.
Inner diameter (mm) · Actual size · Share.
Add a size · Edit size · Saved size.
Save · Delete · Undo.
Settings
Units: Millimeters (mm) · Inches (in).
Default ring size system: US / Canada · UK / Australia · EU / ISO · Japan · China · Russia.
Appearance: System · Light · Dark.
Sizer · Finger · Converter · Saved · Settings.
Next · Get started · Skip.

What’s new

Welcome to True Ring Size — the easy way to find any ring size. Fully offline, no ads, no sign-up.
• Ring mode: resize the on-screen circle to match a ring
• Finger mode: measure your finger directly
• Instant US / UK / EU / JP / CN / RU conversions
• Save sizes for everyone you shop for
Tip: for best accuracy, calibrate the screen to a bank card or AA/AAA battery in Settings.