Okay. You have a plain tumbler, a bag of rhinestones, and a vague idea of what you want to do. Before you start gluing, you need to answer one question: how many stones do I need to cover this thing?
Too few and you are running out mid-project at 11pm. Too many and you are out $20 on stones you will never use. Here is how to get the number right the first time.
The rule of thumb
For a typical tumbler covered in a honeycomb pattern of ss20 stones, Rhinestones Unlimited estimates around 2,500 to 3,000 stones1. That is the working ballpark most rhinestoners start with. If you use smaller stones, the count goes up. If you scatter instead of honeycomb, the count goes down.
Pick your stone size
ss16 and ss20 are the most common sizes for tumblers2. ss16 is slightly smaller and feels finer. ss20 feels bigger and is a little faster to place. ss10 and ss12 give a much finer, glittery look but take more stones to cover the same area.
Scout tip: If this is your first tumbler, start with ss20. Bigger stones are easier to pick up, easier to line up, and the project finishes faster.
Do the math yourself
If you want a tighter number, measure your tumbler (height and circumference), multiply them for surface area, then look up stones per square inch for your stone size. Rhinestones Unlimited's official estimating guide publishes these exact density figures for solid coverage4:
| Stone size | Stones per square inch (solid fill) |
|---|---|
| 12ss | 67.14 |
| 20ss | 29.20 |
For sizes the official guide doesn't specify, Rhinestones Unlimited's "Rhinestones 101" post publishes these figures1:
| Stone size | Stones per square inch (fill) |
|---|---|
| 9ss | 100 |
| 16ss | 49 |
| 30ss | 16 |
Surface area of a typical 20oz tapered tumbler is roughly 55 square inches. Multiply that by 49 for ss16, or by 29.20 for ss20, and you get your full-fill count.
Or just open Scout's Tumbler Calculator, type in your tumbler dimensions, and skip the math.
Choose your pattern
Your pattern changes the count a lot.
Grid. Stones in straight aligned rows. Uses the most stones. Precise look.
Honeycomb. Rows offset by half a stone so each stone nests into the gap. Tighter fill. Most popular for tumblers3.
Scatter. Stones placed with intentional gaps at random spacing. Uses the fewest stones. Forgiving for beginners3.
One more thing: buy extras
Whatever your calculated number is, buy 10 to 15 percent more. Stones drop. Stones crack. Stones roll under the dog bed. Buying a little extra saves you a second shipping charge later.