Can I get a custom ring in a non-standard size like 4.5 or 13?

Yes. Absolutely. A size 4.5 or a size 13 is not a problem at all in a custom piece. In fact, that's one of the main reasons people come to me in the first place.

The real question is whether the jeweler you're working with actually knows how to size a ring properly at the extremes. Most retail chains stock only sizes 5 through 9 and can resize up or down maybe two full sizes before the structure gets weird. A custom job skips that entirely - we build the ring to your exact size from the start.

What changes at size 4.5

A ring that small - and I've made them down to size 3 for some clients - is mostly about proportion. If you take a standard 2mm band and scale it down, the ring looks chunky, the finger-to-band ratio is off, and the stone sits too high relative to the hand. For a size 4.5, I usually drop band width to about 1.6-1.8mm for a solitaire, and shave the thickness down to 1.4-1.5mm. The stone size also has to be scaled in proportion - a 2-carat round on a size 4.5 finger looks like a doorknob. About 1.2 carats is usually the sweet spot for most clients at that size.

What changes at size 13

On the other end, a size 13 band is a lot of metal. The circumference is about 62.2mm, compared to 49.3mm for a size 7. That means about 25% more gold or platinum in the shank alone. The bigger challenge is the stone-to-band proportion again - the same 6mm wide band that looks elegant on a size 7 looks thin and flimsy on a size 13. I typically spec 2.8-3.2mm width for a size 13, with thickness around 1.8-2mm. If a client wants a heavy comfort-fit band for daily wear, I'll go thicker still.

The technical stuff no one tells you

There are a few real constraints at the extremes:

• Tension settings are harder at both ends. At size 4.5, the metal has to grip the stone with almost no room for error. At size 13, the spring tension required to hold a stone securely can make the band uncomfortably thick. I'll usually steer clients to a bezel or cathedral setting instead.
• Engraving on the inside of a size 4.5 band is tight. The text has to be small, usually about 0.5mm tall, and you're limited to about 30-40 characters. On a size 13, you can fit a whole sonnet if you want.
• Resizing later is often not possible for extreme sizes. A size 4.5 can usually go up to a 5.5 or down to 4, but much more and you're cutting the shank and adding a new piece of metal. A size 13 can go down to about 12 or up to 14 without major surgery, but beyond that you're looking at a new shank entirely. This is why I tell clients: get sized properly the first time.

How to get your exact size right

About 30% of the rings I make that come back for sizing were measured wrong by the client or by a clerk with a plastic sizer. A few things that actually work:

• Use a metal ring sizer, preferably a set of individual sizing rings, not the loop-on-a-lanyard kind. The plastic ones flex and give a false reading.
• Measure at room temperature. Cold fingers are smaller. Hot fingers are larger. I tell clients to measure in the morning after coffee, not after a run.
• Measure the knuckle and the base of the finger. If the difference is more than a half size, you need a ring that's sized for the knuckle with a small adjustment bar inside.
• Visit a local jeweler and have them size you with a proper mandrel and sizer set. It should take three minutes. Most will do it for free.

The honest answer

I just finished a ring for a client named Nicole - size 4.75, 1.04 carat old European cut, F/VS2, in a 1.8mm 18k yellow band. It fit perfectly the first time. I'm also working on a men's band for a client named Daniel - size 14.5, comfort-fit, 18k white gold, 3mm wide. That one will take about eight weeks. Both are straightforward jobs for a bench jeweler who does this work regularly.

The only thing that matters is that whoever's making your ring knows how to handle your size. Ask them how many rings they've made at size 4.5 or size 13. If they pause more than a second, find someone else.