Getting Gerbil Bedding Depth Right for Your Own Tank
Gerbil bedding depth depends on who you ask: a 10 cm legal floor, a 20–30 cm charity range, and what each means for your tank.
Table of Contents
Gerbil bedding depth: what 20–30 cm means in a tank
According to the RSPCA’s gerbil housing advice, gerbils need 20–30 cm (about 8–12 inches) of bedding, in a tank ideally around 50 cm high. Other sources give lower figures, and the next section shows who says what.
This guide covers Mongolian gerbils, the usual pet, as the full gerbil tank setup guide for a pair does. It goes deeper on one choice: gerbil bedding depth.
If you’re filling a new tank
Measure the internal height first, then use the litres table to plan how much to buy.
If your gerbils have a few inches now
Many starter cages can’t hold this depth, so you haven’t done anything unusual. The last sections show the fix.
Keeping a hamster? Hamster bedding depth is covered separately.
Gerbil bedding depth by source: 10 cm up to 30 cm
There is no single minimum for gerbils, because law, charities and shelters answer different questions.
Legal minimums vs welfare advice
| Source | Type | Depth | Key Detail |
|---|---|---|---|
| Austria’s legal minimum for gerbils (in German) | Legal minimum | 10 cm | Plus a sand bath |
| Merck Veterinary Manual | Vet reference | About one-third of cage depth | About 14 cm in a 41 cm tank (calculated) |
| Scottish SPCA; Wood Green | Welfare charities | At least 20 cm; 20–25 cm | Wood Green: throughout |
| RSPCA | Welfare charity | 20–30 cm | Tank ideally about 50 cm high |
| Flemish government; Tierschutz beider Basel | Government guide; Swiss foundation | 25 cm (40 better); at least 40 cm | Advice, not law |
We follow the RSPCA’s range, the UK national charity’s specific figure. Blue Cross and PDSA name no depth.
Lower figures still in circulation
🔄 Outdated Advice: Some shelter and retailer care sheets give as little as 1–6 inches (2.5–15 cm). The RSPCA’s 20–30 cm is the current UK charity figure for gerbils.
Why gerbils need this much bedding to dig
Wild gerbils live in large, deep burrows that protect them from weather extremes and predators, according to the RSPCA.
What gerbils do with the depth
The RSPCA wants bedding deep enough to dig and build burrow systems. Merck notes that gerbils hoard food and bury it in their bedding.
What too little looks like
The NC3Rs reports that laboratory gerbils commonly develop repetitive digging without adequate digging facilities. The RSPCA says gerbils digging repeatedly in one corner need more enrichment, more hiding places and a tank with added depth.
🔍 Why It Works: In laboratory work, young gerbils driven to retreat into a burrow, but unable to, developed repetitive digging, and a darkened nest chamber reduced it. That is a finding about burrows, not a depth threshold.
How to measure gerbil bedding depth in your tank
Check your tank in four steps.
- Measure the internal height from the floor to the underside of the lid frame.
- Mark the glass at 20, 25 and 30 cm.
- Press the bedding down gently, then measure from the floor to the surface.
- Subtract that depth from the height, leaving 10–12 cm above it.
Measure after pressing it down
💡 Keeper Tip: Keepers on r/gerbil advise measuring after pressing the bedding down. That is keeper practice, not charity guidance.
Check headroom before adding more
The RSPCA puts an adult gerbil at about 12 cm tall, and the Scottish SPCA asks for at least 10 cm above the bedding. Tank heights: gerbil tank size for a pair.
📊 Tested / Spec: With 12 cm of headroom, a 41 cm tank holds about 28–29 cm of bedding (calculated, not measured). Rims reduce internal height, so measure yours.
How much bedding does a gerbil tank need? Litres by depth
Litres of bedding = floor area in cm² × depth in cm ÷ 1,000.
Litres for common tank sizes
| Tank | 20 cm | 25 cm | 30 cm | Key Detail |
|---|---|---|---|---|
| 20-gallon long, 30×12×12 in (2,320 cm²) | 46 L | 58 L | 70 L | Holds about 18 cm |
| 20-gallon high, 24×12×16 in (1,860 cm²) | 37 L | 47 L | 56 L | Holds about 28 cm |
| 40-gallon breeder, 36×18×16 in (4,180 cm²) | 84 L | 105 L | 125 L | Holds about 28 cm |
| 100×50×50 cm (5,000 cm²), Wood Green’s size for two | 100 L | 125 L | 150 L | Holds about 38 cm |
📊 Tested / Spec: These are calculated loose volumes with 12 cm of headroom, not measured fills. They ignore compaction, tunnels and accessories.
Why the bag label matters
✅ Do This: Compare the litres printed on the bag, not bag counts, and check whether it is compressed.
Will your bedding hold tunnels at 20 cm deep?
Depth only helps if the tunnels hold, and the mix decides that for gerbils.
Mix for structure, not just depth
The RSPCA suggests rough-grained woodchips and hay, which give burrows structure and something to gnaw. Keepers also report pressing the bedding down as they fill. Sources disagree on the safest material, so this guide covers depth only.
⚠️ Watch Out: The RSPCA advises against nesting material that separates into thin strands, such as cotton wool. It suggests ink-free paper, cardboard or hay instead.
Keep some old bedding when you clean
Blue Cross’s gerbil care advice says to put back about a third of the unsoiled used bedding at a full clean.
My tank is too shallow: how to fix gerbil bedding depth
If your tank can’t hold 20–30 cm, the fix is a deeper tank.
If the tank is the problem
The RSPCA describes a gerbilarium with solid glass walls, a secure wire-mesh top and a solid floor. A shallow cage tray can’t hold 20–30 cm. The RSPCA also says to provide one more hiding place, beyond the nest box, than you have gerbils.
If you can’t change tanks yet
Some keepers fill one deep zone and add a wire topper. That is a stopgap below the charity range, since Wood Green asks for 20–25 cm throughout the enclosure.
⚠️ Watch Out: Wood Green warns against three-level glass tanks, where a weaker gerbil can get stuck under a shelf while digging. If a gerbil is hurt or seems unwell, contact a vet experienced with gerbils.
Quick answers about gerbil bedding depth
1. How deep should gerbil bedding be?
The RSPCA recommends 20–30 cm (about 8–12 inches) of gerbil bedding, in a tank ideally around 50 cm high.
2. What is the minimum gerbil bedding depth?
There is no single minimum: Austria’s legal floor is 10 cm, while the RSPCA recommends 20–30 cm of gerbil bedding.
3. How many inches is 20–30 cm of gerbil bedding?
Gerbil bedding of 20–30 cm is about 8–12 inches: 20 cm is 7.9 inches and 30 cm is 11.8 inches.
4. Is 10 cm of bedding enough for gerbils?
Gerbil bedding at 10 cm meets Austria’s legal minimum but is below the RSPCA’s recommended 20–30 cm.
5. Can gerbil bedding be too deep?
Depth is limited by headroom: leave about 12 cm above the gerbil bedding so an adult can stand, as the RSPCA describes.
6. How much bedding does a gerbil tank need?
Floor cm² × depth cm ÷ 1,000 gives litres: about 105 litres of gerbil bedding fills a 40-gallon breeder to 25 cm.
7. Do gerbils still need hides with deep bedding?
Yes: the RSPCA says add hides beyond the nest box, one more than the number of gerbils, even in deep bedding.
8. Why does my gerbil dig in one corner?
The RSPCA says repetitive corner digging calls for more enrichment, more hiding places and a tank with added bedding depth.
9. Can gerbils live in a wire cage with deep bedding?
The RSPCA recommends solid glass walls, a mesh top and a solid floor; a shallow cage tray cannot hold 20–30 cm.
10. How do I stop gerbil tunnels collapsing?
The RSPCA suggests mixing rough-grained woodchips and hay into gerbil bedding for burrow structure; keepers also press it down.
Your next step: mark your tank at 20, 25 and 30 cm
Press your bedding down, measure it against 20 cm, and note the gap. If it falls short, the litres table shows what to buy and the last sections show the fix. Gerbils live in pairs, so plan for two: why gerbils shouldn’t live alone explains why.
