Environmental, Water & Agricultural Chemistry Calculators
All environmental, water & agricultural chemistry calculators in one place.
Water Hardness Calculator
Find total water hardness as CaCO3 from calcium and magnesium levels or a lab EDTA titration, convert instantly between mg/L, grains per gallon, °dH, °fH and °Clark, and estimate lime-soda softening chemical doses, with a hardness scale chart and complete step-by-step working.
Total Alkalinity & Langelier Index (LSI)
Find total alkalinity as CaCO3 from an acid titration or from bicarbonate, carbonate and hydroxide levels, then calculate the Langelier Saturation Index (LSI) from pH, temperature, calcium hardness, alkalinity and TDS to see if water is corrosive, balanced, or scale-forming, with a saturation index scale chart and complete step-by-step working.
Sodium Adsorption Ratio (SAR) for Soil
Find the Sodium Adsorption Ratio (SAR) of soil or irrigation water from sodium, calcium and magnesium in mg/L or meq/L, get the USSL sodium-hazard class (S1-S4), and — with optional inputs — the salinity hazard, residual sodium carbonate (RSC), sodium percentage, magnesium hazard ratio, permeability index and Kelly's ratio, with a sodium-hazard scale chart and complete step-by-step working.
TDS to Electrical Conductivity (EC) Converter
Convert Total Dissolved Solids (TDS) to Electrical Conductivity (EC) or the other way round, in mg/L, g/L, µS/cm, mS/cm or dS/m, choose from standard conversion factors (0.5, 0.55, 0.64, 0.7) or enter your own, compensate for temperature, and get instant drinking-water quality and irrigation salinity-hazard classification with a TDS scale chart and complete step-by-step working.
Biological Oxygen Demand (BOD) Calculator
Calculate BOD5 from a standard dilution or seeded lab test, work out BOD mass load, removal efficiency and population equivalent for a wastewater treatment plant, or find the ultimate BOD using first-order kinetics, with a water quality scale, exertion curve, and complete step-by-step working.
Chemical Oxygen Demand (COD) Calculator
Calculate COD from a standard dichromate reflux titration test, work out COD mass load, removal efficiency and population equivalent for a wastewater treatment plant, or find the BOD5/COD biodegradability ratio, with a water quality scale, comparison chart, and complete step-by-step working.
Soil Fertilizer NPK Ratio & Mass Calculator
Simplify any fertilizer's N-P2O5-K2O grade into its true NPK ratio with total nutrient content and elemental P/K conversion, work out exactly how many kilograms of fertilizer to apply per acre or hectare, or split a nutrient target across urea, DAP and MOP, with charts and complete step-by-step working.
Chlorine Dosing & Residual Water Disinfection
Work out the exact chlorine dose needed for your water's demand and target residual, convert that dose into a real feed rate for liquid bleach, HTH granules or chlorine gas, check your CT value against disinfection log-inactivation credit, or predict how a free chlorine residual decays over time, with charts and complete step-by-step working.
Heavy Metal Concentration Index in Water
Enter measured concentrations for arsenic, lead, cadmium, chromium, mercury and more, and instantly get the Heavy Metal Pollution Index (HPI), Heavy Metal Evaluation Index (HEI), Degree of Contamination (Cd), and Nemerow Pollution Index (NPI) together, with built-in WHO and BIS 10500 permissible limits, a per-metal contamination chart, and complete step-by-step working.