Free online ring sizer
Measure My
Ring Size.
Find the size of a ring you already own — directly on your screen.
A simple three-step process
From ring to size.
Your measurements stay on this device. Nothing is sent anywhere.
- 01 / Calibrate
Calibrate your screen
Match a bank card, ruler, or known-size item to set the scale.
- 02 / Align
Place your ring
Rest your existing ring flat and match its inner edge to the circle.
- 03 / Read14/ IN
Get your ring size
See your closest India, US, UK, and EU sizes instantly.
The measurement tool
Let's find your fit.
Keep your ring and calibration item close by.
- 1Calibrate
- 2Measure
- 3Results
Step 01 / Calibration
Match a real object to your screen.
Adjust the outline to the exact size of something you have in hand. This establishes the scale for your display.
Hold a standard bank or credit card against the screen and match both edges. Rotate it to match the outline. A card is 85.60 × 53.98 mm.
Tip: Remove a thick phone case and keep the object flat against the glass.
Step 02 / Inner diameter
Line up the inside of your ring.
Place your ring flat on the screen. Resize the circle until the inside edge of the ring touches the inside edge of the dark line all around. No ring? Rest your finger lightly on the screen and adjust the circle to roughly match its width at the base for a starting estimate.
Step 03 / Your estimate
Your Ring Size
Closest standard sizes for the inner diameter you measured.
14
7
N½
54
17.3 mm
54.4 mm
This is an estimate. Ring width, finger shape, and calibration or alignment error can affect fit. Check the seller's size chart before buying, especially for valuable or non-resizable jewelry.
Everything runs locally in your browser.
Your guide to the tool
How to measure your ring size online
If you are asking, “How do I measure my ring size?” and you have a ring that already fits, this free ring sizer gives you a practical place to start. Measure My Ring turns your phone, tablet, or computer screen into an adjustable guide for the ring’s inside diameter. After you set the screen scale with a real object, you can match the on-screen circle to your ring and see a size estimate. There is no account to create and no photo to upload.
The tool works best with an existing ring, ideally one worn on the same finger and hand as the new ring you plan to buy. If you do not have a ring, you can place your finger over the on-screen circle to get a rough idea of its size. Finger width alone cannot account for the knuckle or how snugly a ring should fit, so confirm this estimate with a physical ring sizer or jeweler before buying. The tool cannot determine your size from a photo.
1. Calibrate the screen
Open the online ring sizer and choose a standard bank card, ruler, or an item whose dimensions you know. Hold it against the display and adjust the outline until its edges line up. This is essential because the same digital circle can appear at different physical sizes on different screens.
Calibrate again if you zoom the page, rotate the device, or change screens.
2. Match the ring’s inner edge
Lay your ring flat over the guide circle. Use the handle, slider, or plus and minus buttons to change the circle until its edge follows the inside opening of the ring all the way around. Do not include the thickness of the metal band in your measurement. A wide band and a narrow band can have the same outer diameter but different inside diameters. If you have no existing ring, rest your finger lightly on the screen and adjust the circle until it roughly matches the width of your finger at its base. This gives you a starting estimate, not a reliable fit measurement; your knuckle and preferred fit also matter.
Check from directly above, then lift and replace the ring to confirm your reading.
3. Read and compare your size
Select “Show my ring size” to see the measured inner diameter in millimeters, an estimated circumference, and the closest listed sizes for India, the US, the UK, and the EU. These systems label sizes differently, so the millimeter measurement is useful when comparing with a retailer’s ring sizer chart. The chart also lets you look up nearby sizes if your measurement falls between two entries.
The result is an estimate. Conversion tables and band widths vary, so compare it with the seller’s chart before ordering.
Using the ring sizer on your phone
You can measure your ring size on your phone if your ring fits comfortably on the display and you can line up the calibration item accurately. Set the phone on a stable surface and keep the screen awake during measurement. Some small displays leave little space around the ring, which can make the handle harder to use; the slider and buttons offer another way to adjust it. A larger screen may be more comfortable for a large ring.
Screen size alone cannot set the physical scale, so calibrate on every device you use.
A note on accuracy
Measure the ring you have. Know the size you need.
The circle represents the inner diameter of your ring, not its outer edge. A small difference in alignment can change the closest listed size, so calibrate carefully.
Ring size conventions vary slightly between jewelers. Use the millimeter measurement with your seller's chart for the most dependable comparison. For custom or expensive jewelry, confirm the fit with a jeweler.