Want to keep your kids entertained by filling your bath with Orbeez but aren’t sure how many you’ll need? Lucky for you, we’ve gone to the trouble of working out how many are needed for standard bathtubs. We’ve also provided the calculations needed to work out exactly how many you need for your own bath.

## How Many Orbeez Are Required for a Small Bathtub?

According to Badeloft USA, a small bathtub holds approximately 40 gallons of water.

This equates to 9240 cubic inches of volume.

It will take 64 000 Orbeez to fill a small bathtub.

## How Many Orbeez Are Required for a Standard Bathtub?

According to Badeloft USA, a small bathtub holds approximately 80 gallons of water.

This equates to 18480 cubic inches of volume.

It will take 128 000 Orbeez to fill a standard bathtub.

## How Many Orbeez Are Required for a Large Bathtub?

According to Badeloft USA, a small bathtub holds approximately 100 to 110 gallons of water.

This equates to 23100 to 25410 cubic inches of volume.

It will take 160 000 to 176 000 Orbeez to fill a large bathtub.

## How to Work Out the Number of Orbeez You Need to Fill a Bath Yourself

If the above bathtubs aren’t what you have, then you can easily work out the number you need by taking some measurements and completing some basic math. This will provide you with the volume the bath holds and with this measurement you can exactly find the number of Orbeez you need.

For reference:

• One measuring cup contains approximately 100 fully hydrated Orbeez.
• One measuring cup contains 14.4375 cubic inches of volume.

### How to Find the Number of Orbeez Required for a Square or Rectangle Bath

First step is measure the length, width and height of the bathtub. Make sure to measure the inside of the bath and not the outside. Measure in inches and not feet for accuracy.

Note the measurements.

Now multiply the length by the width, and then multiply the resulting number by the height. This number represents the volume in cubic inches.

Now we know the volume of the bath in cubic inches. We also know that one measuring cup contains 14.4375 cubic inches of volume.

To find the volume of the bath in standard measuring cups, we need to divide the volume of the bath by 14.4375.

Now we know the volume of the bath in cups. We also know that one measuring cup contains 100 Orbeez.

To find the number of Orbeez you will need, simply multiply the number of cups by 100.

Example:

Bath length: 60 inches
Bath width: 30 inches
Bath height: 14 inches

60 x 30 x 14 = 25200 cubic inches

25200/14.4375 = 1745.45454545 cups

1745.45454545 * 100 = 174545.454545 Orbeez

Final total = 174 545 Orbeez (more than one hundred and seventy four thousand Orbeez)

### How to Find the Number of Orbeez Required for an Irregular Shaped Bath

An irregular shaped bath may be slightly more difficult to measure, or very difficult, depending on how irregular the shape is.

If the bathtub is a square/rectangle shape and has a bench in it, then it is easy to account for this bench.

Simply follow the math for a square/rectangle tub – measure the inside of the bath as if the bench was not there.

You will now have the volume of the bath, but you will need to remove the space the bench is taking up.

Work out the volume of the bench by taking its length, width and height measurements.

Then subtract the volume of the bench from the volume of the bathtub.

Now you have the volume of the bathtub with a bench built into it.

However, if the bath is a hexagon shape, oval shape or a very irregular rectangle shape then it is much more difficult. You will have to estimate the number of Orbeez for these shapes or use a flow meter to find the volume.

### How to Find Out the Volume of Your Bath Using a Flow Meter

You may already have one on hand as they are often used in the garden. If not, then you can pick them up from any hardware store.

Plug the flow meter into your hosepipe and then fill your bath as much as you can (you may not be able to fill past the overfill drain).

Once your bath is full, turn off the hose and check the measurement from the flow meter.

The flow meter will most likely measure in cubic feet or cubic meters so be aware of this as you will need to convert to cubic inches before you can follow the instructions above.

### Can I Use Generic Orbeez (Water Beads)?

You can use any water beads you like. It’ll certainly be a lot cheaper to use the generic version (water beads) as there are often discount bulk packs that contain tens of thousands of beads.

Be aware that water beads come in various different sizes so be aware that you may find that more or fewer fit in a measuring cup when compared to Orbeez.

### Will Using Tap Water, Filtered Water or Distilled Water Change Things?

Yes, Orbeez will grow to their largest size in distilled water (about 13 or 14mm)

Filtered water will likely still have some contaminants that won’t allow Orbeez to grow quite to their full size.

Tap water could result in your Orbeez growing to a smaller size due to its ionic/mineral content.

### Remember to Leave Space for People to Sit In the Bath

You’ll need to leave space for people to actually get into the bath once it has been filled with Orbeez.

Obviously, if you fill it right to the top and then get in your bath will overflow with Orbeez. So, make sure you take this into account and reduce the number of Orbeez you use.

Also, you will probably want to reduce the total number of Orbeez and add some water so that you can more easily move around.

### Can I Reuse Orbeez or Water Beads That Have Been Used in the Bath?

Yes, you can. But, be aware that bathing in Orbeez will make them dirty/contaminated and mold/bacteria may be an issue.

You can reuse your Orbeez outside (in flowerpots and such), but if you want to reuse them for playtime or in the bath again then you will need to clean then. Cleaning this many Orbeez may not be worth it!

### I Don’t Live In the USA… What About Metric Measurements?

Metric measurements certainly make a lot more sense, but they aren’t used in the US which is why we don’t use them.

With a little bit of thought you can make the calculations work with metric measurements. Probably easiest to measure your bath in centimeters, find the volume in cubic centimeters, and then find the number of US measuring cups of Orbeez you need by finding how many cubic centimeters are in one measuring cup.