Calculator
Example data table
These examples show typical inputs and the recommended inner diameter. Use them to sanity-check your measurements.
| Brush diameter | Side clearance | Shape | Recommended inner size | Recommended depth |
|---|---|---|---|---|
| 80 mm | 10 mm | Round | 100.0 mm | 140.0 mm |
| 90 mm | 12 mm | Square | 114.0 mm (width) | 150.0 mm |
| 70 mm | 8 mm | Round | 86.0 mm | 135.0 mm |
Formula used
- Inner diameter (round): Brush diameter + 2 × side clearance.
- Inner width (square): Inner diameter + corner bonus, to prevent snagging.
- Inner depth: Brush head length + base clearance.
- Opening size: Inner diameter plus extra allowance for slots or lids.
- Outer size: Inner size + 2 × wall thickness.
- Total height: Inner depth + wall thickness + rim lip + optional splash guard.
How to use this calculator
- Measure the brush head diameter and brush head length.
- Select your preferred units, holder shape, and material.
- Set side clearance and base clearance for easy drying.
- Choose a top style and drainage option that fits your space.
- Press Calculate to see results above the form.
- Use Download CSV or Download PDF for printing.
Right-sizing improves hygiene and drying
A holder that is too tight traps moisture and makes the brush hard to remove. This calculator uses your brush head diameter, added side clearance, and the chosen shape to recommend an inner diameter or inner width that lets bristles move freely. Better airflow helps the brush dry faster and reduces odor buildup and lasting hygiene. For shared bathrooms, a compact footprint helps placement beside the toilet, but ensure height keeps the handle easy to grab. Exports help when shopping or comparing wall and floor models.
Clearance settings that match real bathrooms
Side clearance sets how much space surrounds the brush head, while base clearance reserves room for drips and prevents the bristle tips from sitting in pooled water. For daily use, many households prefer moderate clearance so the holder stays compact but still wipes clean easily. If your brush has a thicker head or dense bristles, increase clearance to avoid scraping.
Shape and opening style affect usability
Round holders track the brush diameter closely, while square holders often need extra corner allowance so the head does not snag. Top style also matters: an open top offers the easiest drop-in fit, a slotted insert guides the handle but can restrict entry, and a lid typically needs extra finger space for comfortable access.
Wall thickness and material change outer size
Outer dimensions are calculated by adding wall thickness on both sides. Thicker walls increase stability and reduce wobble, especially for tall handles. Material choice influences practical thickness: plastics can be thinner, ceramic often benefits from sturdier walls, and metal designs may rely on formed edges for strength.
Ventilation and drainage options reduce mess
A small top vent gap encourages evaporation, and the calculator estimates a simple vent area to compare setups. Drain holes can release water into a safe base, while a removable tray makes cleanup quick. If you prefer no drain, plan extra base clearance and rinse the holder routinely to prevent residue.
FAQs
What side clearance should I start with?
Start with 8–12 mm for most brushes. Increase it if bristles are dense, the holder has a slotted top, or you want easier rinsing and quicker drying.
Why does a square holder need extra width?
Corners can catch bristles when inserting or removing the brush. The calculator adds a small corner allowance so the brush head doesn't snag and stays centered.
Do I really need drainage?
Drainage helps if the brush is stored wet. Holes or a tray reduce standing water and odor, but you can skip drainage if you allow more base clearance and clean the holder regularly.
How do I choose wall thickness?
Thicker walls improve stability and durability. Use thicker values for ceramic or tall holders, and thinner values for rigid plastics or metal designs with reinforced edges.
What is the vent gap used for?
A vent gap provides airflow at the top, supporting evaporation. The calculator estimates a simple vent area so you can compare different gaps and opening styles.
Can I use this for wall-mounted holders?
Yes. Use the recommended inner size and opening, then confirm the outer size fits your mounting bracket and available depth. Exported CSV or PDF helps match products in-store.