Understanding Litre Per Day (l/d)
The litre per day measures how many litres of fluid pass a point in one calendar day. It belongs to the volume flow rate family, which tells us “how much volume moves over time.” A litre (L) is the standard metric unit for liquid volume.
Understanding Quart Per Second (qt/s)
A quart per second tells us how many US liquid quarts flow each second. The quart (qt) is the customary‑system counterpart to the litre. Like the litre per day, it is a volume‑over‑time unit, but it works on a much finer time scale.
Conversion Factor: From Litre Per Day to Quart Per Second
1 l/d = 0.00001223 qt/s (rounded to eight decimal places).
How the factor is derived
- Convert the volume: 1 L = 1.05668821 qt (US liquid).
- Convert the time: 1 day = 86 400 seconds.
- Combine the two steps:
\[ \frac{1\;\text{L}}{1\;\text{day}} \times \frac{1.05668821\;\text{qt}}{1\;\text{L}} \times \frac{1\;\text{day}}{86\,400\;\text{s}} = \frac{1.05668821}{86\,400}\;\text{qt/s} \approx 0.00001223\;\text{qt/s} \]
Worked Example: Converting 250 l/d to qt/s
Suppose a small irrigation pump delivers 250 litres each day. To see its rate in quarts per second:
- Start with the factor: 0.00001223 qt/s per l/d.
- Multiply: 250 × 0.00001223 = 0.0030575 qt/s.
- Round to a sensible precision: ≈ 0.00306 qt/s.
The pump moves roughly three thousandths of a quart every second.
Litre Per Day to Quart Per Second Conversion Table
Each row applies the same rule: multiply the litre‑per‑day value by 0.00001223 to obtain quarts per second (rounded to five decimal places).
| Litre Per Day (l/d) | Quart Per Second (qt/s) |
|---|---|
| 1 l/d | 0.00001 qt/s |
| 2 l/d | 0.00002 qt/s |
| 5 l/d | 0.00006 qt/s |
| 10 l/d | 0.00012 qt/s |
| 20 l/d | 0.00024 qt/s |
| 50 l/d | 0.00061 qt/s |
| 100 l/d | 0.00122 qt/s |
| 500 l/d | 0.00612 qt/s |
Practical Applications
- Water‑treatment plants: Engineers often need to translate daily processing capacities into real‑time control set‑points.
- Aquarium hobbyists: Flow‑rate pumps are rated in quarts per second, while water‑change schedules are planned in litres per day.
- Industrial cooling systems: Cooling‑water loops may be specified in metric volumes per day, but valve controllers operate on second‑based flow meters.
- Environmental monitoring: Stream‑flow reports sometimes use litres per day; converting to quarts per second helps compare with US‑based datasets.
Key Takeaways
The conversion between litre per day and quart per second hinges on two constants: 1 L = 1.05668821 qt and 1 day = 86 400 s. Multiplying by the combined factor 0.00001223 gives an accurate, ready‑to‑use result. Use the table above for quick look‑ups, and apply the worked example as a template for any value you encounter.
Need more conversions? Explore our full suite of volume‑flow tools and keep your calculations flowing smoothly.