What Size Tangem Ring Should I Order?

A Tangem Ring can’t be resized. Not by a jeweller, not by anyone. The chip and antenna run through the band, so cutting or stretching it destroys the wallet inside.

That makes sizing the one part of this purchase you can’t fix afterwards. So if you’re wondering what size Tangem Ring you should order, the honest answer is: don’t guess, and don’t rely on a ring size you were told years ago. Measure now, measure properly, and measure at the right time of day.

Here’s how to get it right the first time.

What size Tangem Ring should I order?

Order the size that matches the inner diameter in millimetres of a ring you currently wear comfortably on the finger you intend to use. Tangem sells in US sizes 6 to 13 with no half sizes, so it doesn’t span the full jeweller’s range. Check what’s actually offered before you measure.

If you’ve never had a ring sized, budget ten minutes and use two of the methods below rather than one. Agreement between two methods is worth more than precision in either.

Why this matters more than an ordinary ring purchase

Three things make this different from buying jewellery:

1. No resizing. The electronics are inside the band. There’s no adjustment, ever.
2. It’s a wallet, not an accessory. A ring that slips off is a security problem, not just a loss.
3. Returns are limited. Policies differ depending on whether the ring has been activated.

If it’s too loose, you’ll lose it, probably while pulling your hand out of a jacket pocket. If it’s too tight, you won’t wear it, which defeats the point of buying a wearable wallet at all.

Not sure whether the Ring is the right format for you in the first place? Our comparison of the Tangem Ring against the card sets covers that decision before you get to sizing.

Four ways to measure your ring size

Use at least two. If they disagree, trust the methods in the order below. The first is the most reliable.

1. Measure a ring you already wear

The best method, because it accounts for your knuckle automatically.

Take a ring that fits comfortably on the intended finger. Place it on a flat surface and measure the inside diameter in millimetres, edge to edge across the widest point. A steel ruler works; digital callipers work better.

Match that measurement to the size chart. This is the number that matters, not the size stamped inside the ring, which may be a different national standard.

2. Print Tangem’s sizing guide

Tangem publishes a printable sizing sheet with circles and a paper measuring tool.

Two things people get wrong. Print at 100%, with no “fit to page” and no scaling, because your printer will scale by default. Then verify the printed scale by measuring the ruler on the page against a real ruler, or placing a coin on the matching circle, before you trust anything on it.

A sheet printed at 97% will give you a confidently wrong answer.

3. The string or thread method

Wrap non-stretchy thread or a thin paper strip snugly around the base of your finger. Mark where it overlaps, lay it flat, measure the length in millimetres, and compare against the circumference column in the chart below.

Two cautions. Use thread that doesn’t stretch; elastic or cotton that gives will read small. And if your knuckle is wider than the base of your finger, measure both and choose something between the two, because the ring has to pass over the knuckle and still sit snugly.

This method is the least accurate of the four. Use it as a cross-check rather than your only input.

4. Get measured properly

A jeweller will size you in thirty seconds with a proper ring sizer, usually for nothing. If you’re spending several hundred dollars on something that can’t be adjusted, this is a sensible trip.

You can also buy a plastic ring sizer set online for a few dollars. Worth it if you’re buying as a gift, or buying more than one.

Size chart

Tangem’s published sizes, with a manufacturing tolerance of ±0.25mm:

US size	Inner diameter (mm)	Circumference (mm)
6	16.51	51.87
7	17.35	54.51
8	18.19	57.15
9	18.89	59.34
10	19.84	62.33
11	20.68	64.97
12	21.49	67.51
13	22.33	70.15

Use Tangem’s chart, not a generic one. Ring size standards vary, and a size 9 on a jeweller’s chart isn’t guaranteed to be a size 9 in every manufacturer’s system. Measure in millimetres and match to the manufacturer’s own numbers. If you work in NZ letter sizes, our Tangem Ring size guide for NZ buyers has the letter conversions.

When to measure, and why it matters in New Zealand

Measure at the end of the day, at normal body temperature, when your hands are neither cold nor swollen. Fingers change size through the day and with the weather, and the difference is enough to change your size.

This matters more here than the generic advice suggests, because New Zealand hands do a lot of changing. A cold Dunedin or Central Otago morning will read you a size smaller than you actually are; measure then and the ring will be uncomfortably tight by February. A humid Auckland or Northland summer evening runs the other way, and a measurement taken then may leave you with a ring that slips off in winter.

After exercise, a hot shower, or a long flight, your hands are swollen. Wait. And if you’re in the trades or do manual work, your hands swell through the day, so measure after a normal working day rather than on a Sunday morning.

The practical rule: measure on two or three different days, at different times, and take the middle reading. If your measurements straddle two sizes, read the next section.

Which finger, and which hand

Decide before you measure. The difference between fingers is often a full size or more, and your dominant hand is usually slightly larger.

Think about which hand you use to tap your phone, because the ring needs to be on a hand you can comfortably present to the back of it. If you already wear rings, a wedding band on the same finger changes what’s comfortable. And check whether your work allows it: many New Zealand worksites prohibit rings around rotating machinery. If you’re a mechanic, sparky, builder or working with stock, a ring you remove every shift is a ring you’ll eventually lose, and cards may suit you better.

Most people choose the index or middle finger of their non-dominant hand.

If you are between sizes

Size up, not down. A slightly loose ring is uncomfortable; a ring that won’t pass your knuckle is unusable.

But check it properly before ordering:

• Can it clear your knuckle without forcing? If not, size up regardless of what the base of your finger measures.
• Does it spin freely when you shake your hand? That’s too loose.
• Will you wear it in cold weather? Fingers shrink; a marginal fit becomes a lost ring.

If you land exactly between two sizes and can’t decide, get measured by a jeweller. Thirty seconds beats a wrong order on something you can’t return once activated.

Buying one as a gift

Sizing a ring for someone else without asking is hard. Two approaches that actually work:

1. Borrow a ring they already wear on the relevant finger and measure its inner diameter. Note which finger: you need the right one.
2. Buy the card set instead. Cards need no sizing, cost considerably less, and do exactly the same job. If you’re unsure, this is the sensible gift.

Worth knowing: the Ring ships as a set with backup cards, so you’re not choosing between them. Our article on what comes with the Tangem Ring explains what’s in the box.

FAQs

Measure twice, order once

Ten minutes with a ruler now saves a great deal of frustration later, because this is the one part of the purchase you can’t undo. Once you have your size, the Tangem Ring set ships from Auckland via Tangem NZ, an authorised New Zealand seller, at NZ$320 including GST.