Example preset
Choose a preset to fill the form and refresh results instantly.
Quick check
Pick one tab first: DO, load, or removal rate.
Check units for pressure, concentration, and flow.
Run with sample values before entering field data.
Keep source notes when you export values.
Inputs
Advanced settings
Count backwards (optional)
Results
| DOSaturation concentration | — |
|---|---|
| % saturation | — |
| Shortage amount (saturation - measurement) | — |
| condition | — |
| u（atm） | — |
|---|---|
| θo | — |
| FS | — |
| FP | — |
| Load amount within the period | — |
|---|---|
| Converted per day | — |
| period volume V | — |
| Midway ceremony | — |
| Removal rate R | — |
|---|---|
| Cout_target from target removal rate | — |
| Required removal rate from target Cout | — |
Premise/Source/Caution
- The DO formula adopts the USGS Office of Water Quality Technical Memorandum 2011.03 (Benson & Krause approximation formula).
- The recommended range for DO is 0~40℃, 0~40‰, 0.5~1.1 atm (approximately 507~1114 hPa). Calculation continues even outside the range.
- BOD/COD loads are estimates based on the basic formula: C x Q x Time (1 mg/L = 1 g/m³). Reaction, precipitation, and adsorption are not considered.
- Please do not use it for regulatory judgments or design guarantees, but only for learning and initial estimates.
Reference: USGS WQ 2011.03 / Benson & Krause (1984)
FAQ
What is the difference between DO, BOD, and COD?
Dissolved oxygen (DO) is the oxygen currently available in water. BOD estimates how much oxygen microbes will consume over time, while COD estimates oxygen demand from chemically oxidizable matter. They answer related but different questions.
Why does oxygen saturation change with temperature and salinity?
Warmer or saltier water holds less oxygen at equilibrium. This calculator applies those corrections before converting between mg/L, percent saturation, and deficit.
Can I use these results for compliance or discharge decisions?
No. Use this page for education, field planning, and first-pass checks. Permits and compliance reporting should follow your lab method, local regulations, and official sampling guidance.
Related tools
- Geology/Environment (Water (Rain/Flow rate/Water quality))
- Atmospheric pressure ↔ Altitude (standard atmosphere/sea level correction) (ES-003)
- Nutrient load (N/P): Concentration x flow rate x time → load amount (ES-010)
- Open channel (Manning type) flow rate/flow rate (rectangular/trapezoidal/circular) (ES-013)
- Rainfall (mm) → Volume (m³)/Flow rate (m³/s) conversion (ES-004)