📋 Table of Contents
- What Are the Measurements of a 50 Gallon Fish Tank?
- 50 Gallon Tank Dimensions in CM
- Weight — Empty vs Full
- Fish Tank Volume Calculator in Litres
- Complete Aquarium Size Tables
- 50 Gallon vs 55 Gallon vs 75 Gallon
- Setting Up Your 50 Gallon Tank
- Best Fish for a 50 Gallon Aquarium
- Frequently Asked Questions
- References
What Are the Measurements of a 50 Gallon Fish Tank?
If you are searching for the measurements of a 50 gallon fish tank, you have come to the right place. Whether you are planning your first large aquarium or upgrading from a smaller setup, understanding the exact 50 gallon tank dimensions in cm and inches is essential before you purchase your tank, stand, and equipment.
A standard 50 gallon aquarium measures 36 inches long × 18 inches wide × 19 inches tall — or in metric, approximately 91.4 cm × 45.7 cm × 48.3 cm. This makes it one of the most popular mid-to-large tank sizes in the fishkeeping hobby, offering enough space for a thriving community of fish, live plants, and aquascape décor without the enormous footprint of tanks above 75 gallons.
In this complete guide, we cover everything you need to know about 50 gallon fish tank dimensions, how they compare to other popular tank sizes like the 55 gallon fish tank dimensions in cm and 75 gallon tank dimensions, and we have also included an interactive fish tank volume calculator in litres so you can calculate the exact water volume for any tank shape or size.
Quick Fact: The 50 gallon aquarium sits in the “large aquarium” category. Its wide 18-inch depth front-to-back gives aquascapers more room to create layered layouts compared to the narrower 55 gallon tank (only 13 inches wide).
50 Gallon Tank Dimensions in CM
For those outside the United States or working with metric measurements, here are the exact 50 gallon tank dimensions in cm:
| Measurement | Inches | Centimetres (cm) | Millimetres (mm) |
|---|---|---|---|
| Length | 36″ | 91.4 cm | 914 mm |
| Width (front to back) | 18″ | 45.7 cm | 457 mm |
| Height | 19″ | 48.3 cm | 483 mm |
| Volume | 50 US gallons | — | — |
| Volume (litres) | — | 189.3 litres | 189,270 ml |
Note that these are standard manufacturer dimensions for a typical 50 gallon rectangular glass aquarium. Dimensions may vary slightly by brand (Aqueon, Marineland, Seaclear, etc.) and whether you are buying an acrylic aquarium versus a standard glass tank. Acrylic tanks are typically thinner-walled, meaning the internal dimensions may be slightly larger for the same external footprint.
Why 50 Gallon Tank Dimensions in CM Matter
Knowing the 50 gallon fish tank dimensions in cm is especially important for:
- Measuring the space in your room or cabinet before purchase
- Ordering a custom aquarium stand or cabinet
- Buying a correctly-sized aquarium lid or canopy
- Calculating lighting coverage (measured in cm or inches of tank length)
- Ordering background panels or tank wraps that are cut to size
- Planning aquascape layouts — knowing your aquarium size helps you determine how many plants, rocks, and hardscape elements to buy
Weight of a 50 Gallon Fish Tank — Empty vs Full
One of the most important factors when planning a 50 gallon aquarium setup is understanding the weight — both empty and when fully filled with water, substrate, rocks, and decorations.
A standard 50 gallon fish tank weighs approximately 100 lbs (45 kg) when empty and around 600 lbs (272 kg) when fully set up. This weight calculation varies depending on several important factors.
How Aquarium Weight is Calculated
Water weight calculations in fishkeeping depend on the type of water in your tank. A gallon of freshwater at a specific gravity of 1.000 weighs 8.34 lbs. For saltwater aquariums, the weight increases proportionally with the amount of dissolved salt. For example, 1 gallon of saltwater at a specific gravity of 1.025 equals approximately 8.55 lbs (calculated as 8.34 × 1.025 = 8.5485 lbs). The weight of the water will increase directly proportionate to the weight of the salt being dissolved in the water.
Important: A fully set up 50 gallon fish tank weighs approximately 600 lbs. Never place it on a weak floor, flimsy furniture, or anywhere near walls with inadequate support. Always use a purpose-built aquarium stand rated for this weight. Check your floor’s load-bearing capacity — especially in apartments or older homes.
| Component | Estimated Weight (lbs) | Estimated Weight (kg) |
|---|---|---|
| Empty glass tank | 100 lbs | 45.4 kg |
| Water (50 US gallons freshwater) | ~417 lbs | ~189 kg |
| Water (50 US gallons saltwater @ 1.025) | ~427 lbs | ~194 kg |
| Substrate (2–3 inch layer) | ~40–60 lbs | ~18–27 kg |
| Rocks & decorations | ~20–40 lbs | ~9–18 kg |
| Total (freshwater setup) | ~600 lbs | ~272 kg |
Fish Tank Volume Calculator in Litres
Our interactive fish tank volume calculator in litres lets you calculate the exact water volume of any rectangular aquarium in both US gallons and litres. This is especially useful if you have a custom-sized tank or want to confirm the volume of tanks with non-standard dimensions such as a 60×20×20 tank or a tall aquarium.
Simply enter your tank’s length, width, and height and choose your unit of measurement. The aquarium size calculator will instantly show you the volume in litres, US gallons, and UK gallons.
🧮 Fish Tank Volume Calculator
Enter your tank dimensions below to calculate volume in litres, US gallons & UK gallons.
* Calculated at 100% fill. Subtract 10–15% for substrate, rocks, and headspace in a real setup.
How to Calculate Fish Tank Volume in Litres Manually
If you prefer to calculate manually, use these simple formulas:
- Volume in litres (from cm): Length (cm) × Width (cm) × Height (cm) ÷ 1,000
- Volume in US gallons (from inches): L × W × H (inches) ÷ 231
- Volume in UK gallons (from inches): L × W × H (inches) ÷ 277.4
For example, a 50 gallon tank at 36″ × 18″ × 19″: 36 × 18 × 19 = 12,312 ÷ 231 = 53.3 US gallons (the tank is slightly larger than 50 gallons nominal — this is normal, as manufacturers use nominal gallon ratings).
Complete Aquarium Size Tables — All Common Tank Sizes
Below are the complete aquarium size tables for every common fish tank size, including dimensions, empty weight, and filled weight. These are essential reference tables whether you are looking for 10 gallon tank dimensions in cm, 40 gallon tank dimensions in cm, 55 gallon fish tank dimensions in cm, or planning a large 75 gallon tank.
The weights provided are estimates, as the amount of rock, thickness of glass, and type of water all affect weight calculations.
Small Aquariums
| Tank Size | L × W × H (inches) | Dimensions in cm | Empty Weight | Filled Weight |
|---|---|---|---|---|
| 2.5 gallon | 12″ × 6″ × 8″ | 30.5 × 15.2 × 20.3 cm | 3 lbs | 27 lbs |
| 5 gallon | 16″ × 8″ × 10″ | 40.6 × 20.3 × 25.4 cm | 7 lbs | 62 lbs |
| 10 gallon | 20″ × 10″ × 12″ | 50.8 × 25.4 × 30.5 cm | 11 lbs | 111 lbs |
| 15 gallon | 24″ × 12″ × 12″ | 61 × 30.5 × 30.5 cm | 21 lbs | 170 lbs |
| 15 gallon High | 20″ × 10″ × 18″ | 50.8 × 25.4 × 45.7 cm | 22 lbs | 170 lbs |
Mid-Sized Aquariums
| Tank Size | L × W × H (inches) | Dimensions in cm | Empty Weight | Filled Weight |
|---|---|---|---|---|
| 20 gallon High | 24″ × 12″ × 16″ | 61 × 30.5 × 40.6 cm | 25 lbs | 225 lbs |
| 20 gallon Long | 30″ × 12″ × 12″ | 76.2 × 30.5 × 30.5 cm | 25 lbs | 225 lbs |
| 25 gallon | 24″ × 12″ × 20″ | 61 × 30.5 × 50.8 cm | 32 lbs | 282 lbs |
| 29 gallon | 30″ × 12″ × 18″ | 76.2 × 30.5 × 45.7 cm | 40 lbs | 330 lbs |
| 30 gallon Breeder | 36″ × 18″ × 12″ | 91.4 × 45.7 × 30.5 cm | 48 lbs | 348 lbs |
| 40 gallon Breeder | 36″ × 18″ × 16″ | 91.4 × 45.7 × 40.6 cm | 58 lbs | 458 lbs |
| 40 gallon Long | 48″ × 12″ × 16″ | 121.9 × 30.5 × 40.6 cm | 55 lbs | 455 lbs |
Large Aquariums
| Tank Size | L × W × H (inches) | Dimensions in cm | Empty Weight | Filled Weight |
|---|---|---|---|---|
| 50 gallon ⭐ | 36″ × 18″ × 19″ | 91.4 × 45.7 × 48.3 cm | 100 lbs | 600 lbs |
| 55 gallon | 48″ × 13″ × 21″ | 121.9 × 33 × 53.3 cm | 78 lbs | 625 lbs |
| 65 gallon | 36″ × 18″ × 24″ | 91.4 × 45.7 × 61 cm | 126 lbs | 772 lbs |
| 75 gallon | 48″ × 18″ × 21″ | 121.9 × 45.7 × 53.3 cm | 140 lbs | 850 lbs |
| 90 gallon | 48″ × 18″ × 24″ | 121.9 × 45.7 × 61 cm | 160 lbs | 1,050 lbs |
| 125 gallon | 72″ × 18″ × 21″ | 182.9 × 45.7 × 53.3 cm | 206 lbs | 1,206 lbs |
| 150 gallon | 72″ × 18″ × 28″ | 182.9 × 45.7 × 71.1 cm | 338 lbs | 1,838 lbs |
| 180 gallon | 72″ × 24″ × 25″ | 182.9 × 61 × 63.5 cm | 430 lbs | 1,870 lbs |
| 225 gallon | 72″ × 27.5″ × 27.5″ | 182.9 × 69.9 × 69.9 cm | 358 lbs | 2,158 lbs |
⭐ The 50 gallon tank is highlighted in the table above. Notice that it is shorter in length than the 55 gallon tank but significantly wider (18″ vs 13″), giving it a more square footprint that many aquascapers prefer.
50 Gallon vs 55 Gallon vs 75 Gallon — Which Tank Is Right for You?
Three of the most popular large aquarium sizes are the 50 gallon, 55 gallon, and 75 gallon. Understanding the differences in their dimensions helps you choose the right tank for your space, budget, and fish.
| Feature | 50 Gallon | 55 Gallon | 75 Gallon |
|---|---|---|---|
| Dimensions (inches) | 36×18×19 | 48×13×21 | 48×18×21 |
| Dimensions in cm | 91.4×45.7×48.3 | 121.9×33×53.3 | 121.9×45.7×53.3 |
| Volume (litres) | ~189 L | ~208 L | ~284 L |
| Front-to-back depth | 18″ ✅ Wide | 13″ ❌ Narrow | 18″ ✅ Wide |
| Empty weight | 100 lbs | 78 lbs | 140 lbs |
| Full weight | 600 lbs | 625 lbs | 850 lbs |
| Best for | Aquascaping, community | Schooling fish, budget | Cichlids, reef starter |
| Difficulty (beginner) | ⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐ |
The Key Difference: Width Matters More Than Volume
One of the biggest surprises for new fishkeepers comparing the 50 gallon vs 55 gallon tank is that despite the 55 gallon holding more water, the 50 gallon has a much wider front-to-back dimension (18 inches vs 13 inches on the 55 gallon). This makes the 50 gallon significantly better for:
- Aquascaping — you can create proper foreground, midground, and background planting zones
- Reef tanks — corals need depth to spread and grow naturally
- Fish with territorial behaviour — more width means less conflict
- Filtration placement — easier to hide equipment behind rockwork
Setting Up a 50 Gallon Fish Tank — Essential Tips
Once you understand the measurements of your 50 gallon fish tank, you are ready to plan your setup. Here is a step-by-step overview of what to prepare.
Choosing the Right Location
Before filling your 50 gallon aquarium, check your floor can handle at least 600 lbs concentrated on a small area. The tank’s 36″ × 18″ footprint means most of that weight sits on four stand legs — ensure you are on a ground floor or near a supporting wall. Research by Alrashidi et al. (2025) on automated fish tank management highlights that environmental placement is one of the most critical and often overlooked aspects of long-term aquarium success.
Filtration for a 50 Gallon Tank
For a 50 gallon fish tank, you need a filter rated for at least 200–250 gallons per hour — ideally double the tank volume for heavily stocked tanks. Good options include canister filters (Fluval 307, Eheim Classic 350) or a sump system for saltwater setups. As noted by Boyd (1986) in foundational aquaculture research, proper aeration and water movement are critical to maintaining dissolved oxygen levels that support healthy fish.
Lighting for a 50 Gallon Tank
For a planted 50 gallon aquarium, you need a light that covers the full 36-inch length. LED lights like the Fluval Plant 3.0, Finnex Planted+, or Aqua Illumination Prime are excellent choices. For reef tanks, a higher-PAR LED like the AI Hydra 32 is recommended. The photosynthetic activity of aquatic macrophytes — as studied by Campbell et al. (2025) — produces oxygen bubbles which actually benefit tank inhabitants and create that classic planted tank aesthetic.
Substrate and Aquascaping a 50 Gallon
For planted tanks, use 2–3 inches of nutrient-rich substrate (ADA Aqua Soil, Fluval Stratum) across the tank’s full 36″ × 18″ floor area. For a natural aquascape look, combine substrate with rocks for your fish tank — slate, dragon stone, or seiryu stone work beautifully in this size. For saltwater, use 20–30 lbs of live rock arranged to allow good water flow.
Cycling a 50 Gallon Fish Tank
Before adding fish, you must cycle your tank to establish the nitrogen cycle. This process, studied extensively since the foundational work of Shirer, Cairns & Taller (1968) on measuring fish activity patterns in controlled water systems, typically takes 4–8 weeks. Use bottled beneficial bacteria (Seachem Stability, Fritz Zyme 7) to speed up the process. Monitor ammonia, nitrite, and nitrate daily until readings stabilize.
Pro Tip: Always subtract 10–15% of your tank volume for actual usable water when stocking fish. A 50 gallon tank with 3 inches of substrate and rocks actually holds roughly 40–43 gallons of water. Use our fish tank volume calculator in litres above to get exact numbers for your setup.
Best Fish for a 50 Gallon Aquarium
With its spacious 36″ × 18″ × 19″ dimensions, a 50 gallon aquarium opens up a wide range of stocking options. Here are some excellent choices:
Freshwater Fish for a 50 Gallon Tank
- Angelfish — 4–6 fish, need the height of this tank
- Rainbow fish — schooling species that love the width; keep 6+ for best behaviour
- Discus — 4–5 fish (need very stable water parameters)
- African cichlids — 8–12 mbuna in a species-only setup
- Large community — tetras, corydoras, danios, livebearers mixed
- Siamese fighting fish (betta) — a single betta in a planted 50 gallon is stunning
- Goldfish — 3–4 fancy goldfish (oranda, shubunkin, ryukin) with strong filtration
Saltwater / Reef Fish for a 50 Gallon
- Clownfish pair — classic choice, easy to keep
- Royal gramma — beautiful purple and yellow reef fish
- Firefish goby — peaceful, striking red and white colouration
- Tailspot blenny — algae grazer, great personality
- Orchid dottyback — vibrant purple, reef safe
As documented in early marine aquaculture research by Houde and Ramsay (1971), maintaining stable water parameters — temperature, salinity, and pH — is the single most important factor in successfully keeping both freshwater and saltwater fish long term.
Frequently Asked Questions
What are the exact measurements of a 50 gallon fish tank?
A standard 50 gallon fish tank measures 36 inches long × 18 inches wide × 19 inches tall (91.4 cm × 45.7 cm × 48.3 cm). It weighs 100 lbs empty and approximately 600 lbs when fully set up with water, substrate, and decorations.
What are 50 gallon tank dimensions in cm?
In metric, the 50 gallon tank dimensions in cm are: 91.4 cm (length) × 45.7 cm (width) × 48.3 cm (height). The water volume is approximately 189.3 litres.
How many litres is a 50 gallon fish tank?
A 50 US gallon fish tank holds approximately 189.3 litres. In UK gallons, that is approximately 41.6 UK gallons. Use our fish tank volume calculator in litres above to calculate any custom tank size.
What are the dimensions of a 55 gallon fish tank in cm?
A standard 55 gallon fish tank dimensions in cm are: 121.9 cm (length) × 33 cm (width) × 53.3 cm (height). Note that the 55 gallon is notably narrower (33 cm wide) than the 50 gallon (45.7 cm wide) despite being slightly longer.
What are the 75 gallon tank dimensions cm?
The 75 gallon tank dimensions in cm are: 121.9 cm (length) × 45.7 cm (width) × 53.3 cm (height). It weighs 140 lbs empty and approximately 850 lbs when full.
What are 10 gallon tank dimensions in cm?
A standard 10 gallon tank dimensions in cm are: 50.8 cm (length) × 25.4 cm (width) × 30.5 cm (height), equivalent to 20″ × 10″ × 12″ in inches. It weighs 11 lbs empty and 111 lbs when full.
What are 40 gallon tank dimensions in cm?
The popular 40 gallon breeder tank dimensions in cm are: 91.4 cm (length) × 45.7 cm (width) × 40.6 cm (height) (36″ × 18″ × 16″). The 40 gallon long measures 121.9 cm × 30.5 cm × 40.6 cm (48″ × 12″ × 16″).
Is a 50 gallon tank good for beginners?
Yes — a 50 gallon aquarium is actually easier for beginners than smaller tanks. Larger water volumes are more stable and forgiving of minor mistakes in feeding or water changes. Water parameters (pH, ammonia, temperature) fluctuate more slowly in 50 gallons than in a 10 gallon nano tank.
📚 References & Further Reading
- Alrashidi, T., et al. (2025). “Automated Fish Tank Management System.” — Research on automated monitoring systems for aquarium water quality and environmental management.
- Campbell, K., Cerezke-Riemer, Y., & Acorn, J.H. (2025). “Photosynthetic oxygen bubble stream sounds from aquatic macrophytes, and their consequences for acoustic biodiversity inventories and acoustic communication in shallow freshwater settings.” PloS One, 20(4), e0317424.
- Shirer, H.W., Cairns Jr, J., & Taller, W.T. (1968). “A Simple Apparatus for Measuring Activity Patterns of Fishes.” JAWRA Journal of the American Water Resources Association, 4(3), 27–43.
- Houde, E.D. & Ramsay, A.J. (1971). “A culture system for marine fish larvae.” The Progressive Fish-Culturist, 33(3), 156–157.
- Boyd, C.E. (1986). “A method for testing aerators for fish tanks.” The Progressive Fish-Culturist, 48(1), 68–70.
Related guides