Cv Calculator for Liquids The coefficient of flow (Cv) is a formula which is used to determine a valve's flow under various conditions and to select the correct valve for a flow application. Cv expresses the flow in gallons per minute of 60°F water with a pressure drop across the valve of 1 psi. The formula becomes more intricate for gases, as gases are compressible fluids and are thus affected by temperature. Furthermore, two formulas are required to accurately estimate flow. When the upstream pressure equals or exceeds two times the downstream pressure, it is known as "choked flow" and requires the Critical Flow formula. If the upstream pressure is less than two times the downstream pressure, the Sub-Critical flow formula is utilized. Don't worry, we have simplified the process and built the two formulas into our calculator. Just input the application parameters and we will do the rest! This Cv and Flow calculator can help you select the right valve for a given application providing you with either the Cv or the Flow Rate. Enter the application parameters below: Calculate Cv for Liquids Calculate Cv for Gases Cv = Q * √(G/(P1-P2) Critical Flow Cv = Q * √(G * T) / (816* P1) Sub-Critical Flow Cv = (Q/962) * √((G * T) / (P12* P22)) Q (GPM)= Q (SCFH) = P1= P1= P2= P2= G= T= G= Cv= Cv= Calculate Flow Rate for Liquids (GPM) Calculate Flow Rate for Gases (SCFH) Q = Cv * √(dP/G) Critical Flow Q = Cv * (816 * P1)/ √(G * T) Sub-Critical Flow Q = 962 * Cv  * √((P12* P22) / (G * T)) Cv= Cv= P1= P1= P2= P2= G= T= G= Q (GPM)= Q (SCFH) = Cv = Valve flow coefficient Cv = Valve flow coefficient Q  = Volumetric flow rate (SCFH - Standard Cubic Feet / Hour) Q  = Flow rate (GPM - Gallons per Minute) P1 = Inlet Pressure (psia) P1 = Inlet Pressure (psia) P2 = Outlet Pressure (psia) P2 = Outlet Pressure (psia) T = Temperature (F) G = Specific Gravity of the liquid G = Specific Gravity of the gas
 Liquid Specific Gravity Gas Specific Gravity Acetaldehyde CH3CHO 0.79 Acetylene (ethyne) - C2H2 0.899 Acetic acid 5% - vinegar 1.006 Air 1 Acetic acid - 10% 1.014 Alcohol vapor 1.601 Acetic acid - 50% 1.061 Ammonia - NH3 0.59 Acetic acid - 80% 1.075 Argon - Ar 1.38 Acetic acid - concentrated 1.055 Arsine 2.69 Acetic acid anhydride (CH3COO)2O 1.087 Benzene - C6H6 2.6969 Acetone CH3COCH3 0.792 Blast Furnace gas 1.02 Alcohol - allyl 0.855 1,2 - Butadiene - C4H6 1.8676 Alcohol - butyl-n 0.81 Butane - C4H10 2.0061 Alcohol - ethyl (grain) C2H5OH 0.789 1-Butene (Butylene)- C4H8 1.9372 Alcohol - methyl (wood) CH3OH 0.79 Isobutene - C4H8 1.94 Alcohol - propyl 0.804 Carbon dioxide - CO2 1.5189 Aluminum sulfate 36% solution 1.055 Carbon monoxide - CO 0.9667 Ammonia 0.662 Carbureted Water Gas 0.63 Aniline 1.022 Chlorine - Cl2 2.486 Automotive crankcase oils 0.88-0.94 Coke Oven Gas 0.44 Automotive gear oils 0.88-0.94 Cyclobutane 1.938 Beer 1.01 Cyclohexane 2.9057 Benzene (benzol) C6H6 0.899 Cyclopentane 2.4215 Benzine 0.69 Cyclopropane 1.451 Bone oil 0.918 n - Decane 4.9125 Boric acid H3BO3 1.014 Deutrium - D2 0.07 Bromine 2.9 Digestive Gas (Sewage or Biogas) 0.8 Butane-n 0.584 2,3 - Dimethylbutane 2.9753 Butyric acid 0.959 2,2 - Dimetylpentane 3.4596 Calcium chloride 5% 1.04 Diisobutyl 3.9439 Calcium chloride 25% 1.23 Ethane - C2H6 1.0378 Carbolic acid (phenol) 1.08 Ether vapor 2.586 Carbon tetrachloride CCl4 1.594 Ethylbenzene 3.6655 Carbon disulfide CS2 1.293 Ethyl Chloride - C2H5Cl 2.23 Castor Oil 0.96 Ethylene (Ethene) - C2H4 0.9686 China wood oil 0.943 3 - Ethylpentane 3.4596 Chloroform 1.489 Fluorine 1.31 Coconut oil 0.925 Helium - He 0.138 Cod liver oil 0.920-0.925 n - Heptane 3.4596 Corn oil 0.924 n - Hexane 2.9753 Cotton seed oil 0.88-0.93 Hydrogen 0.0696 Creosote 1.04-1.10 Hydrogen chloride - HCl 1.268 Crude oil 48o API 0.79 Hydrogen sulfide - H2S 1.1763 Crude oil 40o API 0.825 Hydrofluoric acid 2.37 Crude oil 35.6o API 0.847 Hydrochloric acid 1.261 Crude oil 32.6o API 0.862 Illuminating gas 0.4 Crude oil Salt creek 0.843 Isobutane 2.0068 Decane-n 0.73 Isobutene 1.9372 Diethylene glycol 1.12 Isooctane 3.9439 Diethyl ether 0.714 Isopentane 2.4911 Diphenylamine 1.16 Isoprene 2.3519 Diesel Fuel Oil 2D/3D/4D/5D 0.81 - 0.96 Isopropylbenzene 4.1498 Dowtherm 1.056 Krypton 2.89 Ether, sulfuric 0.72 Marsh gas 0.555 Ethyl acetate CH3COOC2H3 0.907 Mercury vapor 6.94 Ethyl bromide C2H3Br 1.45 Methane - CH4 0.5537 Ethylene bromide 2.18 Methylcyclopentane 2.9057 Ethylene chloride 1.246 Methylcyclohexane 3.39 Ethylene glycol 1.125 Methyl Chloride 1.74 Fluoric acid 1.5 2 - Methylhexane 3.4596 Formic acid - 10% 1.025 2 - Methylpentane 2.9753 Formic acid - 50% 1.121 Natural Gas (typical) 0.60 - 0.70 Formic acid - 80% 1.186 Neohexane 2.9753 Formic acid - concentrated 1.221 Neopentane 2.4911 Trichlorofluoromethane - 11 1.49 Neon 0.697 Dichlorodifluoromethane - 12 1.33 Nitric oxide - NO 1.037 Dichlorofluoromethane - 21 1.37 Nitrogen - N2 (pure) 0.9669 Furfurol 1.159 Nitrogen - N2 (atmospheric) 0.9723 Fuel oils 1/2/3/5A/5B/6 0.82-0.95 Nitrous oxide - N2O 1.53 Gas oils 0.89 n - Nonane 4.4282 Gasoline a 0.74 n - Octane 3.9439 Gasoline b 0.72 Oxygen - O2 1.1044 Gasoline c 0.68 Ozone 1.66 Glycerine 100% 1.26 n - Pentane 2.4911 Glycerine 50% water 1.13 Phosgene 1.39 Glucose 1.35-1.44 Propane - C3H8 1.5219 Heptane-n 0.688 Propene (Propylene) - C3H6 1.4529 Hexane-n 0.664 Sasol 0.42 Ink printers 1.0-1.4 Silane 1.11 Kerosene 0.78-0.82 Styrene 3.5959 Jet fuel 0.82 Sulfur Dioxide - SO2 2.264 Lard 0.96 Toluene - Methylbenzene 3.1082 Lard oil 0.91-0.93 Triptane 3.4596 Linseed oil 0.92-0.94 Water gas (bituminous) 0.71 Mercury 13.6 Water vapor 0.6218 Methyl acetate 0.93 Xenon 4.53 Methyl iodide 2.28 o - Xylene 3.6655 Mineral oil 0.92 Milk 1.02-1.05 Molasses A first 1.40-1.46 Molasses B second 1.43-1.48 Molasses C blackstrap 1.46-1.49 Muriatic acid 1.2 Naphtha 0.76 Naphthalene 1.145 Neatsfoot oil 0.917 Nitric acid 1.5 Nitrobentzene 1.203 Nonane-n 0.722 Octane-n 0.707 Olive oil 0.91 - 0.92 Palm oil 0.924 Peanut oil 0.92 Pentane-n 0.65 Petroleum oil 0.82 Phosphoric acid 1.78 Potassium hydrate 1.24 Rape oil 0.92 Sodium chloride 1.19 Sodium hydrate 1.27 Sulphuric acid 1.84 Tar 1 Tuluol 0.87 Turpentine oil 0.87 Vinegar 1.08 Water. fresh 1 Water. sea 36 oF 1.02 Whale oil 0.92 Xylene 0.87