YOUR SCREENYour phoneAutomatic screen setup
1. Set the screen scale
Supported phones set up automatically. You can correct the phone choice; unsupported screens have a preview and optional ruler setup.
Ring Sizer
No ring? Start with your finger.
Estimate your size on your phone, without an app.
- 1Your screen
- 2
- 3Your estimate
Your phone becomes the guide
We’ll try to set the scale automatically. On a supported phone, you can go straight to matching your finger.
Checking your phone’s screen…
Choose or correct my phone
Model-based scale · physical accuracy not yet validated. Display specifications
Model not listed? Explore an example with .
Other device? Set the scale with a ruler
Optional: line up the left end with 0 on a physical ruler. Adjust the right end to 20 mm (2 cm).
0 to 20 mm · 2 cm
Match the sides of your finger
Rest your finger gently where a ring will sit. Look straight down and match each line to one side. Don’t press.
Place the base of your finger here
Place your ring here
Fine-tune with ±. This measures visible width, not circumference.
Your estimated size
Finger-width estimateUS6
UKL
EU ≈52
JP11
How do I line up a ring?
Alignment diagrams, not to scale. Look straight down at a flat, round ring.
Optional: check the screen scale
Compare this line with 20 mm on a physical ruler. If it does not match, change the screen setup before measuring.
20 mm
This checks display scale, not finger shape or fit.
No ring needed No app to install Free to use
Your phone, your finger, three steps
A width-based estimate. No existing ring required.
Match both sides
2. Match finger width
Rest your finger lightly. Match the guides to the sides where the ring will sit. You can check the knuckle separately.
EXAMPLE ESTIMATEUS 6Compare nearby sizes
3. Review your estimate
See approximate international sizes, compare nearby sizes and save the result with its measurement method.
A starting point
for a better fit
Finger mode matches visible width, then looks up the size of a ring with a similar inside diameter. It does not measure circumference or guarantee comfort.
Published screen specifications set the model-based scale. Physical device accuracy and finger-width sizing have not yet been validated.
Understand the estimateOne reference,
four size systems
Compare US, UK, EU and JP references. Brand charts can differ; check the retailer’s sizing before ordering.
Explore the full size chart| US | UK | EU ≈ | JP |
|---|---|---|---|
| 5 | J | 49 | 9 |
| 5.5 | K | 51 | 10 |
| 6 | L | 52 | 11 |
| 6.5 | M | 53 | 13 |
| 7 | N | 54 | 14 |
| 7.5 | O | 56 | 15 |
| 8 | P | 57 | 16 |
| 8.5 | Q | 58 | 17 |
| 9 | R | 60 | 18 |
Common sizes · GIA reference · Approximate conversions
What finger width tells you
Finger width is one visible dimension. This tool treats it as an equivalent circular diameter for a rough size lookup. Finger shape and pressure can change the estimate.
We do not calculate a “measured circumference” from finger width or add unvalidated temperature and knuckle corrections.
Check the knuckle
A ring must pass over the joint and sit comfortably at its intended position. Record the knuckle width separately if it appears wider.
A wider knuckle does not translate into one universal allowance. A physical fitting remains the best final check.
Already have a ring?
Switch to ring mode and match the inside opening of a ring worn on the intended finger. This reads inner diameter rather than estimating from soft tissue.
Measure an existing ringMore ways to find your size
Finger sizing FAQs
What you need, how to measure and what your result means.
Estimate from finger widthLearn how finger-width estimates differ from measured ring diameters.
How the estimate worksCan I find my ring size without a ring?
Yes. Finger mode lets you match two on-screen guides to your finger’s visible width, then estimates a nearby ring size. Supported phones set up automatically. If automatic setup is unavailable, choose your exact phone or use optional ruler setup. The estimate treats width as an equivalent circular diameter; it does not measure your finger’s circumference.
Do I need a ruler, credit card or printer?
No extra measuring tool is required when automatic setup or a matching phone display preset is available. Presets are based on published screen specifications and have not yet been physically validated. Other devices can use the optional ruler setup, or explore a clearly labelled preview. No credit card or printer is used.
How accurate is measuring a finger on a screen?
Finger-width sizing is an approximation. Finger shape, pressure, alignment and display scale affect the result. A matching screen preset does not prove physical accuracy, and this tool has no validated measurement tolerance. Confirm fit with a physical finger gauge or jeweler before an important purchase.
Can this website detect my phone automatically?
On supported Android browsers, we request the phone model and match it to a screen preset. Current Android presets cover Google Pixel 8, 8 Pro, 9, 9 Pro, 9 Pro XL and Samsung Galaxy S24, S24+ and S24 Ultra. iPhone 13, 14, 15, 16, 16 Plus and 16 Pro presets can match their screen configuration, but the browser cannot identify an exact iPhone model. Screen matches are estimates, not physical validation. If identification is unavailable or ambiguous, choose your exact listed model or use the preview. Pro, Plus and Ultra variants are not interchangeable.
Where should I place my finger?
Hold your phone flat and look straight down. Rest the intended finger gently along the guides at the place the ring will sit. Do not press into the glass. Adjust both guides to touch the visible sides of your finger, then lift and repeat if alignment is uncertain.
Why check the knuckle as well?
A ring must pass over your knuckle and fit at the base. The optional knuckle check records its visible width separately. A wider knuckle is a reason to confirm fit; we do not automatically add a fixed allowance or claim to measure its circumference.
Does this tool measure finger circumference?
No. Finger mode measures visible width on a screen and treats that width as an approximate equivalent diameter for size lookup. Fingers are not perfect circles. The tool does not label this estimate as a measured circumference.
Do I need to install an app or create an account?
No. The tool runs in your browser and requires no account or payment. Measurement processing stays on your device. Your selected phone preset may be remembered in this browser; no camera access is requested.
Can I save or share my result?
Yes. After confirming a measurement using a matching model preset or a physical ruler scale, save a PNG showing the method, width or inner diameter, approximate sizes and scale basis. Preview examples cannot be saved as measurements.
Can I still measure a ring I already own?
Yes. Choose “I have a ring”, set the screen scale, then match the gold circle’s outside edge to your ring’s inside opening. Ring mode reads an inner diameter; finger mode estimates from visible finger width. Both provide approximate size conversions.