Printable
Printable ring size chart
Paper does not have a pixel density problem, so a correctly printed sizer is the most reliable home method there is. The catch is printer scaling — which is why this sheet carries a calibration bar you check before you trust it. How every tolerance on the site is derived is set out on theaccuracy page.
- 01
Print at 100%
In the print dialog set scale to 100%. Turn off “fit to page” and “shrink oversized pages” — they are on by default in most browsers.
- 02
Check the bar
Hold a bank card against the printed calibration bar. If it does not match exactly, fix the scaling and print again.
- 03
Match your ring
Lay a ring that fits over the circles. The one whose outline just disappears under the band is your size.
Ring sizer — print at 100% scale
ringsizeai.com · sizes shown at true diameter
Step 1 — calibration bar. This must be exactly one bank card wide.
If your card is wider or narrower than this box, the page did not print at 100%.
Step 2 — place your ring over the circles
- US 4H · 47 · 14.9mm
- US 5J · 49 · 15.7mm
- US 6L · 52 · 16.5mm
- US 7N · 54 · 17.3mm
- US 8P · 57 · 18.1mm
- US 9R · 60 · 18.9mm
- US 10T · 62 · 19.8mm
- US 11V · 65 · 20.6mm
- US 12X · 67 · 21.4mm
- US 13Z · 70 · 22.2mm
Each circle is the inside diameter of that size. The correct circle is the one whose outline is just covered when you lay the ring on top. Sizes follow ISO 8653; allow ±0.1 mm for manufacturing tolerance.
Print scaling
Why a printed sizer usually comes out the wrong size
Nothing about this sheet is approximate. Every circle is drawn in CSS millimetres, and the CSS specification pins one inch to 96 pixels for printed output, so the file that reaches your printer describes a physically exact diameter. What goes wrong happens after that, in the print dialog, and it goes wrong silently — a sheet printed at 96% looks completely normal on the paper. There is nothing on it to compare against, which is exactly why the calibration bar exists.
Four settings account for nearly every bad print. Fit to pageis the usual culprit: most browsers enable it by default, and it shrinks the sheet by a few per cent so the content clears the printer's unprintable margin.Shrink oversized pages in Chrome and Edge does the same thing under a different name. A scale percentage left at 90 or 110 from whatever you printed last will carry over. And theprinter driver has its own scaling, separate from the browser's — a driver set to "fit to printable area" will undo a browser set to 100%. Set both to 100% and nothing else.
Printing from a phone is where this fails most often. AirPrint and Android's print service add their own scale-to-fit stage that you frequently cannot turn off, so the sheet arrives one to four per cent small. If you have no other option, print it anyway and check the calibration bar — but expect to need a desktop or a saved PDF to get a clean result. Saving to PDF first and printing the PDF from a proper reader with scaling off is the most reliable route on any device.
One more thing worth knowing: printers are not perfectly accurate machines even when nothing is scaling. A consumer inkjet or laser will place a line within about 0.2 to 0.5 mm of where it was asked to, and paper stretches slightly as it takes ink. That is small next to a whole ring size — one US size is 0.81 mm of diameter — but it is the reason a printed sizer is good to roughly a quarter of a size rather than a tenth. The full error budget is on theaccuracy page.
Paper size
A4 or US Letter — the sheet works on both, but only one way
A4 is 210 × 297 mm. US Letter is 216 × 279 mm — about 6 mm wider and 18 mm shorter. The sizer is laid out to fit inside the smaller dimension of each, so the circles and the calibration bar land on the page whichever stock is loaded. The danger is not the paper itself; it is the mismatch. If the document is set to A4 and the tray holds Letter, the printer or driver will helpfully rescale to fit, and now every circle is wrong by the ratio between the two — roughly three per cent, or a little over a third of a US size at the middle of the range.
So set the paper size in the print dialog to whatever is actually in the tray, and leave scaling at 100%. Do not use the paper-size dropdown to force a fit. If your printer refuses to print without some scaling, print the sheet in landscape instead — the layout tolerates it, and the calibration bar will tell you either way.
Paper stock matters less than people expect. Ordinary 80 gsm copier paper is fine. Avoid glossy photo paper, which can absorb ink unevenly at the edges of a fine dashed line, and avoid anything thick enough that a ring will not sit flat against it. Do not print onto card and then cut the circles out — measuring against the printed outline is more accurate than measuring against a hole you cut by hand.
Verification
Check the card bar before you trust a single circle
Every bank card, credit card, debit card and driving licence in the world is made to ISO/IEC 7810 ID-1: 85.6 mm by 53.98 mm, to a tolerance tighter than a tenth of a millimetre. That makes the card in your wallet a better reference object than most household rulers, and it is why the same object calibrates both this sheet and theon-screen sizer.
Lay a card flat on the printed calibration bar and line up the left edges. The card's right edge should sit exactly on the box's right edge. Check the height as well — a print that is correct across but short down the page means the paper fed at an angle, and a re-print will fix it. Sight down the page rather than looking at it from an angle; parallax over a 85 mm span is easily half a millimetre.
If the card overhangs, the page printed small; if the box is wider than the card, it printed large. Either way the fix is the same — correct the scaling and print again — because there is no useful way to compensate mentally. It is worth knowing what the error costs, though. The bar is 85.6 mm wide, so a card that overhangs by 1 mm means the sheet printed at about 98.8%. At the middle of the range that shifts a 17.3 mm circle by roughly 0.2 mm, which is about a quarter of a US size. A 3 mm discrepancy — the A4-to-Letter mismatch — is closer to a third of a size, and enough to have a ring come back for resizing.
Once the bar checks out, the circles are trustworthy and the rest is straightforward. Lay a ring that already fits over each circle in turn; the right one is the circle whose dashed outline just disappears behind the inside of the band. If the ring falls between two, take the larger. Measure at the end of the day rather than first thing, and not straight after a hot shower or a cold walk — finger size moves by up to half a US size across a normal day.
With a size in hand, convert it wherever you need to: theUS ring size chartgives every US size in millimetres alongside the UK letter, theinternational chartadds EU/ISO, Indian and Japanese, andaverage ring size for womenis the sanity check when you are buying for somebody who cannot be measured. For the other four home methods and how they rank against each other, seehow to measure ring size at home.