Swarovski crystal sizes explained, with a full SS to mm chart

When it comes to adding sparkle to your project, Swarovski crystals are a favourite choice. They come in a wide range of sizes, and knowing which one to reach for makes all the difference between a design that looks just right and one that feels a bit off. This guide gives you the full SS to mm conversion, plus simple advice on which size suits which project, whether you're placing tiny stones for nail art or covering a costume in big statement sparkle.

How Swarovski crystal sizes work

Swarovski flatback rhinestones are measured in SS, which stands for stone size. Each SS number corresponds to a measurement in millimetres, and the rule is simple: the higher the number, the bigger the crystal. For example, SS5 is around 1.8mm, while SS20 is roughly 5mm.

Swarovski allows around a 0.2mm margin either side, due to the manufacturing process, but this is such a tiny amount that it is not noticeable to the naked eye. Knowing these conversions is useful because some projects need very small crystals for detail, while others need larger stones to cover a big area or make a statement.

It's worth knowing that SS is the standard sizing system for rhinestones in general, not just Swarovski. So once you're comfortable reading SS sizes, you can apply the same knowledge to whichever brand you're working with.

Swarovski size chart, SS to mm

Here's a quick guide to the most popular Swarovski flatback rhinestone sizes and how they convert to millimetres.

Size	mm (approx)	Great for
SS2	1.4mm	Fine detail, gap filling, delicate nail art
SS3	1.5mm	Nail art, tooth gems, fine detail, gap filling
SS4	1.6mm	Fine detail, curved lines
SS5	1.8mm	Fine detail, nail art
SS6	2mm	Nail art, detailing
SS7	2.2mm	Detailing, gap filling
SS8	2.4mm	Detailing
SS9	2.8mm	Detailing, small accents
SS10	3mm	Bridal, accessories, cardmaking, face gems, all-round bling
SS12	3.2mm	Clothing, accessories, all-round
SS14	3.5mm	Clothing, dance costumes
SS16	4mm	Most popular all-rounder, garments, dancewear
SS20	5mm	Most popular all-rounder, bridal, shoes, handbags
SS30	6mm	Irish dance, theatre costumes, large-area coverage
SS34	7mm	Statement pieces, interior textiles
SS40	8.5mm	Bold statement, furniture, large projects
SS48	11mm	Show-stopping statement stones

The two most popular sizes deserve a closer look, since they're the ones people ask about most. SS16 measures around 4mm (more precisely 3.8mm to 4.0mm), and SS20 measures around 5mm (more precisely 4.6mm to 4.8mm). Both are brilliant all-rounders, which is why they turn up again and again across garments, dancewear and accessories.

If you'd like a tangible sense of scale, the image below shows how the sizes compare to a 5p coin, handy for picturing the real thing before you order.

What size Swarovski crystals should I use?

This is one of the most common questions we're asked, and the answer depends on what you're embellishing. To make it easy, we've grouped the sizes into three bands.

Small, SS2 to SS9 (roughly 1.4mm to 2.8mm) 

Best for intricate, detailed designs. These small sizes are ideal for nail art, tooth gems (small crystals applied to teeth), face and body gems, and delicate detailing on clothing or accessories. They're also perfect if your design follows curved lines, where a smaller stone sits more neatly around the shape.

Medium, SS10 to SS20 (roughly 3mm to 5mm)

 These are the most popular all-rounder sizes. They're perfect for clothing customisation, bridal wear, shoes, handbags, accessories, craft projects, cardmaking, and freestyle, ballroom or ice-skating costumes. If you're not sure where to start, a size in this band is usually a safe bet. You'll find these sizes in both non hotfix and hotfix options, so you can pick the application method that suits your project.

Large, SS30 to SS48 (roughly 6mm to 11mm) 

Larger stones are great for making a statement and covering big areas quickly. They're commonly used for Irish dance dresses, theatrical costumes, furniture, interior textiles, and bold fashion pieces such as shoes and handbags. Because they cover more space with fewer stones, they're ideal for big-impact designs.

Top tip: small crystals such as SS3 to SS7 are great for filling the gaps left between larger stones, or tucking into corners and edges. If you apply large crystals in a straight line, you'll end up with little empty spaces between them. Filling these with a tiny crystal keeps everything looking neat and gap-free.

For more ideas like this, see our guide to rhinestone application styles.

How to measure a crystal you already have

If you're reordering to match an existing design, or repairing a piece that's lost a stone or two, measuring is the most reliable way to get the size right.

• Measure the flatback straight across its widest point, in millimetres.

• Match that figure to the chart above to find the SS size.

• Order the matching size, and your new stones will sit perfectly alongside the originals.

This little step saves a lot of guesswork, especially on repairs where an exact match really matters.

Tips for choosing the right Swarovski size

• Mix sizes for depth:  Combining small and large stones creates texture and extra sparkle. This is known as the 'rockery effect', and it's very handy if you're unsure what size to go with.

• Think about scale: Small crystals are best for fine detail, while larger ones give standout sparkle and cover big areas.

• Think about weight: Lightweight fabrics can stretch and lose their shape under large, heavy crystals, so stick to smaller sizes on delicate materials.

• Test before you commit: Trying a tester crystal or checking a size chart helps you see what works best before you place a full order. Just contact us for free samples.

SS and PP sizing, what's the difference?

You may sometimes see crystal sizes written as PP rather than SS, so it helps to know the difference.

• SS (stone size) is the standard system for round flatbacks and rhinestones, and it's the one you'll use most of the time.

• PP (pearl plate) is an older system used mainly for the very smallest stones, along with chatons and pointed-back crystals.

In both systems, a higher number means a bigger stone. When the two are quoted together, the millimetre measurement is always the most precise reference, so if in doubt, go by the mm figure.

Swarovski crystals come in a size for every project, from tiny SS2 detail stones right up to bold SS48 statement crystals. Each size has its place, whether you're creating delicate nail art or a fully crystallised theatre costume. The key is simply choosing the size that suits your design best.

If you're still unsure which to pick, don't worry, our team at Crystal Parade are always happy to help. You can also order samples to try before you buy, so you can see the sparkle in person before committing to your full order.