A bow front aquarium has flat side and back panels and a front glass that curves outward. The shape widens the view, but to calculate its volume you add the volume of the curved segment to that of the flat part.
This calculator treats the bow as a circular segment: the volume of the flat part (length × width × height) plus the segment that the curved front glass adds.
How is the volume of a bow front aquarium calculated?
Gross volume (litres) = (length × width + bow segment area) × height ÷ 1000. The bow segment is a circular segment whose chord is the length and whose height is the bow depth.
How to take the measurements
- Measure the length across the front, from one end to the other on the outside.
- Measure the width from the back glass to the straight line where the curve starts.
- Measure the bow depth: from the straight line between the two front corners to the farthest point of the front glass.
- Measure the height and glass thickness, then enter the advanced settings.
Worked example
For a bow front aquarium with length 100 cm, width 40 cm, bow depth 10 cm, height 50 cm, the gross volume is 233.6 litres. With 0.8 cm glass, no substrate and 2 cm of headroom, the net water volume is 210.7 litres.
Example sizes and their volumes
| Length (cm) | Width (cm) | Bow depth (cm) | Height (cm) | Gross (L) | Net water (L) | Net water (US gal) |
|---|---|---|---|---|---|---|
| 80 | 35 | 8 | 45 | 145.4 | 129.1 | 34.1 |
| 100 | 40 | 10 | 50 | 233.6 | 210.7 | 55.7 |
| 120 | 50 | 15 | 55 | 396.8 | 363.3 | 96 |
| 150 | 50 | 15 | 60 | 540.7 | 498.6 | 131.7 |
Net water volume assumes 0.8 cm glass, 0 cm substrate and 2 cm headroom; results are approximate.
Frequently asked questions
How do I measure the bow depth?
Measure from the straight line joining the two front corners to the farthest point of the curved glass. The width is measured from the back glass to that same straight line.
How much more water does a bow front hold than a flat tank of the same size?
The bow adds a circular segment to the flat tank; the larger the bow depth, the bigger the difference. Try a bow depth close to 0 and then your real value to see the difference directly.
When should I use the bow front calculator instead of the half cylinder one?
When the front is a shallow arc rather than a full half circle and the side panels are flat, the bow front calculator is more accurate.