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All Physical Constants

This is a very comprehensive list of most physical constants needed to perform routine (and some not-so-routine) tasks. Oddly enough (and scarily enough), a search on the Internet, and printed texts as well, will turn up sometimes significantly different values for these "constants."

As with all endeavors of importance, you are advised to collaborate the values presented here with a second source that you trust.

Name Value Unit
Absolute Entropy Constant -1.1517048  
Absolute Entropy Constant -1.1648678  
Absolute Zero -273.15  °C
Acceleration of Free Fall on Earth 9.80665  m/s^2
Acceleration of Free Fall on Earth 32.174  ft/s^2
Acre 4046.856422  m^2
Air Density 1.2929  kg/m^3
Air Viscosity @ (20°C) 0.000018  N s/m^2
Alladi-Grinstead Constant 0.809394021  
Ångström 1E-10  m
Année-lumière ly 9.46053E+15  m
Apéry's Constant 1.202056903  
Apothecaries' Ounce 0.031103477  kg
Astronomical Unit AU 1.49598E+11  m
Atmospheric Pressure 101325  N/m^2
Atmospheric Pressure 1.01325  bar
Atmospheric Pressure 14.7  lbf/in^2
Atomic Mass Unit 1.66054E-27  kg
Atomic Mass Unit 931.494013  MeV
Atomic Mass Unit 1.49242E-10  J
Avogadro Constant NA 6.02214E+23  mol-1
Avoirdupois Ounce oz 0.028349523  kg
Avoirdupois Ounce oz 0.0625  lb (av.)
Avoirdupois Ounce oz 16 drachms (av.)
Backhouse's Constant 1.456074949  
Base of Natural Logarithms 2.718281828  
Bernstein's Constant 0.280169499  
Board Foot (Timber) 0.002359737  m^3
Bohr Magneton 9.27401E-24  J/T
Bohr Magneton 5.78838E-05  eV/T
Bohr Magneton 13996246240  Hz/T
Bohr Radius 5.29177E-11 m
Boltzmann Constant 1.38065E-23   J/K
Boltzmann Constant 8.61734E-05     eV/K
Boltzmann Constant 20836644000    Hz/K
Briggsian logarithm log10(2) 0.301029996  
Brun's Constant B 1.902160582  
Cahen's Constant 0.62946502  
Carbon-14 Half-life of T 5570 years
Catalan's Constant 0.915965594  
Chain 20.1168  m
Characteristic Impedence of Vacuum 376.7303135  Ohm
Charge to Mass Quotient(Electron) -1.75882E+11  C/kg
Charge to Mass Quotient (Proton) 95788340.8  C/kg
Charge (Electron) 1.60218E-19  C
Charge (Electron) 2.41799E+14  A/J
Charge (Electron Specific) -1.75882E+11 C/kg
Charge (Elementary) 1.60218E-19  C
Charge (Elementary) 2.41799E+14  A/J
Circulation (Quantum) 0.000363695  m2/s
Circulation (Quantum) 0.00072739  m2/s
Classical Electron Radius 2.81794E-15  m
Common Logarithm of 2 log10(2) 0.301029996  
Compton Wavelength of Electron 2.42631E-12  m
Compton Wavelength (Muon ) 1.17344E-14 m
Compton Wavelength (Neutron) 1.31959E-15 m
Compton Wavelength (Proton) 1.32141E-15 m
Compton Wavelength (Tau) 6.977E-16 m
Conductance Quantum 7.74809E-05 S
Conductance (Quantized Hall) 3.87405E-05 S
Copper (Linear Expansivity) 0.000017 K-1
Copper (Specific Heat Capacity) 385 J kg-1 K-1
Copper (Thermal Conductivity) 385 W/m/K
Copper (Young Modulus) 1.3E+11  Pa
Cord (Timber UK) 3.624556364  m^3
Critical Temperature of Air -190  °C
Cross Section (Thomson) 6.65246E-29 m^2
Cube Foot 0.028316847  m^3
Cube Inch 1.63871E-05  m^3
Cube Yard 7.64555E-05  m^3
Curie 37000000000  Bq
Dalton 1.66054E-27  kg
Dalton 931.494013  MeV
Dalton 1.49242E-10  J
Daniel Cell (emf) 1.08  V
Density of Air (at stp) 0.7734  m^3/kg
Density of Air (at stp) 1.2929  kg/m^3
Density (Earth's Average) 5517  kg/m^3
Deuteron Magnetic Moment 4.33074E-27  J/T
Deuteron Magnetic Moment 0.000466975  µB
Deuteron Magnetic Moment 0.85743823  µN
Deuteron Molar Mass 2.013553214  u
Deuteron Rest Mass 3.34359E-27  kg
Deuteron Rest Mass 2.013553214  u
Deuteron Rest Mass 1875.61339  MeV/c^2
Deuteron-Electron Magnetic Moment Ratio 0.000466435  
Deuteron-Electron Rest Mass Ratio 3670.483014  
Deuteron-Proton Magnetic Moment Ratio 0.307012204  
Deuteron-Proton Rest Mass Ratio 1.999007496  
Dirac's Constant 1.05457E-34  J s
Dirac's Constant 6.58212E-16  eV s
Drachm (Avoirdupois) 0.001771845  kg
Dry Pint (US) 0.00055061  m^3
e 2.718281828  
Earth's Average Density 5517  kg/m^3
Earth's Average Radius 6370000  m
Earth's Magnetic Field (Horizontal Component) 0.000018  T
Earth's Mass 5.972E+24  kg
Earth-Moon Mean Distance 384400000  m
Electric Constant 8.85419E-12  F/m
Electron Charge 1.60218E-19  C
Electron Charge 2.41799E+14  A/J
Electron Charge to Mass Quotient -1.75882E+11  C/kg
Electron g-Factor -2.002319304  
Electron Gyromagnetic Ratio 1.76086E+11  s-1 T-1
Electron Gyromagnetic Ratio 28024.954  MHz/T
Electron Magnetic Moment -9.28476E-24  J/T
Electron Magnetic Moment -1.001159652  
Electron Magnetic Moment -1838.281966  
Electron Magnetic Moment Anomaly 0.001159652  
Electron Mass 9.10938E-31  kg
Electron Mass 0.00054858  u
Electron Mass 0.510998902  MeV
Electron Molar Mass 5.4858E-07  kg/mol
Electron Radius (Classical) 2.81794E-15  m
Electron Specific Charge -1.75882E+11  C/kg
Electron to Shielded Helion Magnetic Moment Ratio (gas sphere 25°C) 864.058255  
Electron to Shielded Proton Magnetic Moment Ratio (H2O sphere 25°C) -658.2275954  
Electron-a-Particle Mass Ratio 0.000137093  
Electron-Deuteron Magnetic Moment Ratio -2143.923498  
Electron-Deuteron Mass Ratio 0.000272444  
Electron-Muon Magnetic Moment Ratio 206.766972  
Electron-Muon Mass Ratio 0.004836332  
Electron-Neutron Magnetic Moment Ratio 960.9205  
Electron-Neutron Mass Ratio 0.000543867  
Electron-Proton Magnetic Moment Ratio -658.2106875  
Electron-Proton Mass Ratio 0.000544617  
Electron-Tau Mass Ratio 0.000287555  
Electronvolt 1.60218E-19  J
Elementary Charge 1.60218E-19  C
Elementary Charge 2.41799E+14  A/J
emf of Daniell Cell 1.08  V
emf of Lechlanché Cell 1.46  V
emf of Nife Cell 1.4  V
emf of Weston Cell 1.0186  V
Energy Production (Sun's) 3.9E+26  W
Energy (Hartree) 4.35974E-18  J
Energy (Hartree) 27.2113834  eV
Euler's Constant 0.577215665  
Faraday Constant 96485.3415  C/mol
Fathom fath 1.8288  m
Fathom fath 72  in
Fathom fath 6  ft
Feigenbaum's Constant 4.669210609  
Fermi Constant 1.4E-50  J m-3
Fermi Coupling Constant 1.16639E-05  GeV-2
Fine Structure Constant 0.007297353  
First Radiation Constant 3.74177E-16  W m2
First Radiation Constant for Spectral Radiance 1.19104E-16  W m^2/sr
Fluid Ounce UK 0.00002841  m^3
Fluid Ounce US 0.00002957  m^3
Foot 0.3048  m
Foot (Board Timber) 0.002359737  m^3
Foot (Cube) 0.028316847  m^3
Foot (Cube) 1728  in^3
Fransén-Robinson Constant 2.807770242  
Free Neutron (Half-life) 650  s
Free Space (Permeability) 1.25664E-06  N/A^2
Free Space (Permittivity) 8.85419E-12  F/m
g-Factor (Electron) -2.002319304  
g-Factor (Muon) -2.002331832  
g-Factor (Neutron) -3.82608545  
g-Factor (Proton) 5.585694675  
Gallon (UK) 0.004546  m^3
Gallon (UK) 1.201  US gallon
Gallon (US) 0.003785  m^3
Gallon (US) 0.833  UK gallon
Gas Constant 8.314  J K-1 mol-1
Gas Constant 8.314472  J mol-1 K-1
Geepound 14.59390294  kg
Glass (Refractive Index) 1.5  
Glass (Thermal Conductivity) 1  W m-1 K-1
Gold Number 1.618033989  
Golden Mean 1.618033989  
Golomb-Dickman Constant 0.624329989  
Grain 0.06479  g
Gravitation (Newtonian Constant) 6.673E-11  m^3 kg-1 s-1
G/hc 6.707E-39  (GeV/c2)-2
Gravitational Acceleration (Moon's) 1.619  m s-2
Gravitational Constant 6.673E-11  N m^2 kg-2
Gravity (Acceleration) 9.80665  m s-2
Gravity (Acceleration) 32.174  ft s-2
Gunter's Chain 20.1168  m
Gyromagnetic Ratio (Electron) 1.76086E+11  s-1 T-1
Gyromagnetic Ratio (Electron) 28024.954  MHz T-1
Gyromagnetic Ratio (Neutron) 183247188  s-1 T-1
Gyromagnetic Ratio  (n/2p) 29.1646958  MHz T-1
Gyromagnetic Ratio (Proton) 267522212 m s-1 T-1
Gyromagnetic Ratio (Proton) 42.5774825  MHz T-1
Gyromagnetic Ratio (Shielded Proton H2O sphere 25°C) 267515341  /s/T
Hafner-Sarnak-McCurley Constant 0.353236372  
Half-life of Carbon-14 5570  years
Half-life of Free Neutron 650  s
Hard Square Entropy Constant 1.503048082  
Hartree Energy 4.35974E-18  J
Hartree Energy 27.2113834  eV
Hectare 104  m^2
Horizontal Component of Earth's Magnetic Field 0.000018  T
Hundredweight (UK) 50800  g
Hundredweight (Short US) 45350  g
Hydrogen Rydberg Number 10967758  m-1
Impedence of Vacuum Z0 376.7303135  Ohm
Imperial Pint 0.0005682  m^3
Inch 0.254  m
Inch (Cube) 1.63871E-05  m^3
International Nautical Mile 1852  m
Inverse Conductance Quantum     12906.403786 Ohm  
Inverse Fine Structure Constant 0.137036  
Josephson Frequency-Voltage Quotient 4.83598E+14  Hz/V
Khintchine's Constant 2.685452001  
Landau-Ramanujan Constant 0.764223653  
Laplace Limit Constant 0.662743419  
Lechlanché Cell (emf) 1.46  V
Length (Planck) 1.616E-35  m
Lengyel's Constant 1.098685806  
Lieb's Square Ice Constant 1.539600718  
Light Year 9.46053E+15  m
Light Speed of (in a Vacuum) 299792458  m/s
Linear Expansivity of Copper 0.000017  K-1
Linear Expansivity of Steel 0.000012  K-1
Liquid Pint (US) 0.0004731  m^3
Litre 0.001  m^3
Loschmidt Constant 2.68678E+25  m-3
Loschmidt Constant (T=273.15K; p=100kPa) 0.022710981  m^3/mol
Madelung's Constant -1.615542627  
Magnetic Constant 1.25664E-06  N A-2
Magnetic Flux Quantum 2.06783E-15  Wb
Magnetic Moment Anomaly (Electron) 0.001159652  
Magnetic Moment Anomaly (Muon) 0.001165916  
Magnetic Moment Ratio (Deuteron-Electron) 0.000466435  
Magnetic Moment Ratio (Deuteron-Proton)  0.3070122035(51)  
Magnetic Moment Ratio (Electron to Shielded Helion gas sphere 25°C)  864.058255(10)  
Magnetic Moment Ratio (Electron to Shielded Proton H2O sphere 25°C)  -658.2275954(71)  
Magnetic Moment Ratio (Electron-Deuteron) -2143.923498  
Magnetic Moment Ratio (Electron-Muon) 206.766972  
Magnetic Moment Ratio (Electron-Neutron) 960.9205  
Magnetic Moment Ratio (Electron-Proton) -658.2106875  
Magnetic Moment Ratio (Muon-Proton) -3.18334539  
Magnetic Moment Ratio (Neutron to Shielded Proton H2O- sphere- 25°C)  -0.68499694(16)  
Magnetic Moment Ratio (Neutron-Electron) 0.001040669  
Magnetic Moment Ratio (Neutron-Proton) -0.68497934  
Magnetic Moment Ratio (Proton-Neutron) -1.45989805  
Magnetic Moment (Deuteron)      0.43307375(15)e-26  J/T
Magnetic Moment (Deuteron) 0.000466975  µB
Magnetic Moment (Deuteron) 0.85743823  µN
Magnetic Moment (Electron µe) -9.28476E-24  J/T
Magnetic Moment (Electron µe/µB) -1.001159652  
Magnetic Moment (Electron µe/µN) -1838.281966  
Magnetic Moment (Muon µµ) -4.49045E-26  J/T
Magnetic Moment (Muon µµ/µB) -0.004841971  
Magnetic Moment (Muon µµ/µN) -8.8905977  
Magnetic Moment (Neutron µn) -9.66236E-27  J/T
Magnetic Moment (Neutron µn/µB0 -0.001041876  
Magnetic Moment (Neutron µn/µN) -1.91304272  
Magnetic Moment (Proton µp) 1.41061E-26  J/T
Magnetic Moment (Proton µp/µB) 0.001521032  
Magnetic Moment (Proton µp/µN) 2.792847337  
Magneton (Bohr) 9.27401E-24  J/T
Magneton (Bohr) 5.78838E-05  eV/T
Magneton (Bohr) 13996246240  Hz/T
Magneton (Nuclear) 5.05078E-27  J/T
Magneton (Nuclear) 3.15245E-08  eV/T
Magneton (Nuclear) 7.62259396  MHz/T
Mass Ratio (Deuteron-Electron Rest) 3670.483014  
Mass Ratio (Deuteron-Proton Rest) 1.999007496  
Mass Ratio (Electron-a-Particle) 0.000137093  
Mass Ratio (Electron-Deuteron) 0.000272444  
Mass Ratio (Electron-Muon) 0.004836332  
Mass Ratio (Electron-Neutron) 0.000543867  
Mass Ratio (Electron-Proton) 0.000544617  
Mass Ratio (Electron-Tau) 0.000287555  
Mass Ratio (Muon-Electron) 206.7682657  
Mass Ratio (Muon-Neutron) 0.112454508  
Mass Ratio (Muon-Proton) 0.112609517  
Mass Ratio (Muon-Tau) 0.0594572  
Mass Ratio (Neutron-Electron) 1.838683655  
Mass Ratio (Neutron-Muon) 8.89248478  
Mass Ratio (Neutron-Proton) 1.001378419  
Mass Ratio (Neutron-Tau) 0.528722  
Mass Ratio (Proton-Electron) 1836.152668  
Mass Ratio (Proton-Muon) 8.88024408  
Mass Ratio (Proton-Neutron) 0.998623479  
Mass Ratio (Proton-Tau) 0.527994  
Mass Ratio (Tau-Electron) 3477.48  
Mass Ratio (Tau-Muon) 16.8188  
Mass Ratio (Tau-Neutron) 1.89135  
Mass Ratio (Tau-Proton) 1.89396  
Mass (Deuteron Rest) 3.34359E+27  kg
Mass (Deuteron Rest) 2.013553214  u
Mass (Deuteron Rest) 1875.61339  MeV/c^2
Mass (Earth's) 5.972E+24  kg
Mass (Sun's) 1.99E+30  kg
Mass (Tau) 3.16788E-27  kg
Mass (Tau) 1.90774  u
Mile 1609.344 m
Mile (Square) 2589000 m^2
Mills' Constant 1.306377884  
Molar Gas Constant 8.314472  J mol-1 K-1
Molar Mass (Deuteron) 2.013553214  u
Molar Mass (Electron) 5.4858E-07  kg/mol
Molar Mass (Muon) 0.000113429  kg/mol
Molar Mass (Neutron) 0.001008665  kg/mol
Molar Mass (Proton) 0.001007276  kg/mol
Molar Mass (Tau NAmt) 0.00190774  kg/mol
Molar Planck Constant 3.99031E-10  J s/mol
Molar Planck Constant 0.119626565  J m/mol
Molar Volume (Ideal Gas T=273.15 K p=101.325 kPa) 0.022413996  m^3 mol-1
Moon's Gravitational Acceleration 1.619  m/s^2
Moon's Mean Density 3330  kg/m^3
Moon's Mean Distance from Earth 384400000  m
Moon's Mean Mass 7.33E+22 kg
Moon's Mean Radius 1738000  m
Muon Compton Wavelength 1.17344E-14  m
Muon g-Factor -2.002331832  
Muon Magnetic Moment -4.49045E-26  J/T
Muon Magnetic Moment -0.004841971  
Muon Magnetic Moment -8.8905977  
Muon Magnetic Moment Anomaly 0.001165916  
Muon Mass 1.88353E-28  kg
Muon Mass 0.113428917  u
Muon Mass 105.6583568  MeV
Muon Molar Mass 0.000113429  kg/mol
Muon-Electron Mass Ratio 206.7682657  
Muon-Neutron Mass Ratio 0.112454508  
Muon-Proton Magnetic Moment Ratio -3.18334539  
Muon-Proton Mass Ratio 0.112609517  
Muon-Tau Mass Ratio 0.0594572  
Naperian (natural) logarithm ln(10) 2.302585093  
Naperian (natural) logarithm ln(2) 0.693147181  
Nautical Mile (International) 1852  m
Nautical Mile (UK) 1853.18  m
Neutron Compton Wavelength 1.31959E-15  m
Neutron g-Factor -3.82608545  
Neutron Gyromagnetic Ratio 183247188  /s/T
Neutron Gyromagnetic Ratio 29.1646958  MHz/T
Neutron Magnetic Moment -9.66236E-27  J/T
Neutron Magnetic Moment -0.001041876  
Neutron Magnetic Moment -1.91304272  
Neutron Mass 1.67493E-27  kg
Neutron Mass 1.008664916  u
Neutron Mass 1.50535E-10  J
Neutron Molar Mass 0.001008665  kg/mol
Neutron to Shielded Proton Magnetic Moment Ratio (H2O- sphere- 25°C) -0.68499694  
Neutron-Electron Magnetic Moment Ratio 0.001040669  
Neutron-Electron Mass Ratio 1.838683655  
Neutron-Muon Mass Ratio 8.89248478  
Neutron-Proton Magnetic Moment Ratio -0.68497934  
Neutron-Proton Mass Ratio 1.001378419  
Neutron-Tau Mass Ratio 0.528722  
Newtonian Constant of Gravitation 6.673E-11  m^3 kg-1 s-1
Newtonian Constant of Gravitation 6.707E-39  (GeV/c2)-2
Nife Cell (emf) 1.4  V
Niven's Constant 1.70521114  
Nuclear Magneton 5.05078E-27  J T-1
Nuclear Magneton 3.15245E-08  eV T-1
Nuclear Magneton 7.62259396  MHz T-1
Number (Gold) 1.618033989  
Ounce (Apothecaries) 0.031103477  kg
Ounce (Avoirdupois) 0.028349523  kg
Ounce (Avoirdupois) 0.0625  lb (av.)
Ounce (Avoirdupois) 16  drachms (av.)
Ounce (Troy) 31.103  g
Paraffin (Refractive Index) 1.42  
Permeability of Free Space 1.25664E-06  H/m
Permittivity of Free Space 8.85419E-12  F/m
Pi 3.141592654  
Pint (Dry US) 0.00055061  m^3
Pint (Imperial) 0.0005682  m^3
Pint (Liquid US) 0.0004731  m^3
Planck Constant (h) 6.62607E-34  J s
Planck Constant (h) 4.13567E-15  eV s
Planck Constant (h/2p) 1.05457E-34  J s
Planck Constant (h bar) 6.58212E-16  eV s
Planck Constant (Molar) 3.99031E-10  J s/mol
Planck Constant (Molar) 0.119626565  J m/mol
Planck Length 1.616E-35  m
Planck Mass 2.1767E-08  kg
Planck Time 5.3906E-44  s
Porter's Constant 1.467078079  
Pounds per Acre 0.112  g/m^2
Pounds per Foot 1.488  kg/m
Pounds per Inch 17.85  kg/m
Pounds per Square Foot 4882  g/m^2
Pounds per Square Inch 703000  g/m^2
Pounds per Yard 0.496  kg/m
Pressure (Atmospheric) 101325  N/m^2
Pressure (Atmospheric) 1.01325  bar
Pressure (Atmospheric) 14.7  lbf in-2
Proton Charge to Mass Quotient 95788340.8  C/kg
Proton Compton Wavelength h/mpc 1.32141E-15  m
Proton g-Factor 5.585694675  
Proton Gyromagnetic Ratio 267522212  s-1 T-1
Proton Gyromagnetic Ratio 42.5774825  MHz/T
Proton Magnetic Moment 1.41061E-26  J/T
Proton Magnetic Moment 0.001521032  
Proton Magnetic Moment 2.792847337  
Proton Magnetic Moment (Shielded H2O- sphere- 25°C) 1.41057E-26 J/T
Proton Mass 1.67262E-27  kg
Proton Mass 1.007276467  u
Proton Mass 1.50328E-10  J
Proton Molar Mass 0.001007276  kg/mol
Proton-Electron Mass Ratio 1836.152668  
Proton-Muon Mass Ratio 8.88024408  
Proton-Neutron Magnetic Moment Ratio -1.45989805  
Proton-Neutron Mass Ratio 0.998623479  
Proton-Tau Mass Ratio 0.527994  
Pythagoras' Constant 1.414213562  
Quantized Hall Conductance 3.87405E-05 S
Quantized Hall Resistance 25812.8056  
Quantum of Circulation 0.000363695  m^2/s
h/me 0.00072739  m^2/s
Quantum Conductance 7.74809E-05  S
Quantum Inverse Conductance 12906.40379  Ohm
Quantum Magnetic Flux 2.06783E-15 Wb
Radiation Constant (Second) 0.014387752 m K
Ramanujan-Soldner Constant 1.451369235  
Refractive Index of Glass 1.5  
Refractive Index of Paraffin 1.42  
Refractive Index of Water 1.33  
Residual Entropy For Square Ice 1.539600718  
Resistance Quantized Hall RH 25812.8056 Ohm
Rydberg Constant 10973731.57  m-1
Rydberg Constant 3.28984E+15  Hz
Rydberg Constant 2.17987E-18  J
Rydberg Number (Hydrogen) 10967758  m-1
Sackur-Tetrode Constant -1.1517048  
Sackur-Tetrode Constant -1.1648678  
Second Radiation Constant 0.014387752  m K
Self-Numbers Density Constant 0.252660259  
Shapiro's Cyclic Sum Constant 0.4945668  
Short Hundredweight (US)          4.535e4 g  
Short Ton 907100  g
Short Ton 2000  lb
Siegbahn Unit 1.00021E-13  m
Sierpinski's Constant 2.58498176  
Sigma 1E+12  m
Siriometre 1.49598E+15  m
Siriusweit 1.54284E+17  m
Slug 14.59390294  kg
Solar Constant 1400  W m-2
Specific Heat Capacity of Copper 385  J kg-1 K-1
Specific Heat Capacity of Water 4200  J kg-1 K-1
Specific Latent Heat of Fusion of Water 334000  J kg-1
Specific Latent Heat of Vapourisation of Water 2260000  J kg-1
Spectral Radiance (First Radiation Constant) 1.19104E-16  W m^2 sr-1
Speed of Light in a Vacuum 299792458  m/s
Speed of Sound in Air at STP 340  m/s
Square Mile 2589000  m^2
Square Yard 0.8361  m^2
Steel (Linear Expansivity) 0.000012  K-1
Steel (Young Modulus) 2.1E+11  Pa
Stefan-Boltzmann Constant 5.6704E-08  W m-2 K-4
Sun's Energy Production 3.9E+26  W
Sun's Mass 1.99E+30  kg
Sun's Mean Distance From Earth 1.495E+11  m
Sun's Mean Radius 696000000  m
Tau Compton Wavelength 6.977E-16  m
Tau Mass 3.16788E-27  kg
Tau Mass 1.90774  u
Tau Molar Mass 0.00190774  kg mol-1
Tau-Electron Mass Ratio 3477.48  
Tau-Muon Mass Ratio 16.8188  
Tau-Neutron Mass Ratio 1.89135  
Tau-Proton Mass Ratio 1.89396  
Thermal Conductivity of Copper 385  W m-1 K-1
Thermal Conductivity of Glass 1  W m-1 K-1
Thomson Cross Section 6.65246E-29  m^2
Ton 106  kg
Ton Short 907100  g
Ton UK per 1000yd 1.111  kg/m
Ton UK per Mile 0.6313  kg/m
Troy Ounce 31.103  g
Vallée's Constant 0.199458818  
Van der Corput's Constant 3.364317578  
Verdet's Constant (Light at 589nm in water) 0.000477  rad/A
Viscosity of Air at 20°C 0.000018  N s/m^2
Viscosity of Water at 20°C 0.001002  N s/m^2
von Klitzing Constant 25812.80757  Ohm
Water (Refractive Index) 1.33  
Water (Specific Heat Capacity) 4200  J/kg/K
Water (Specific Latent Hear of Vapourisation) 2260000  J/kg
Water (Specific Latent Heat of Fusion) 334000  J/kg
Water (Viscosity 20°C) 0.001002  N s/m^2
Wavelength of Electron Compton 2.42631E-12  m
Weak Mixing Angle 0.2224  
Weston Cell emf 1.0186  V
Wien Displacement Law Constant 0.002897769  m K
Wilbraham-Gibbs Constant 1.851937052  
Young Modulus for Copper 1.3E+11  Pa
Young Modulus for Steel 2.1E+11  Pa
Zero Absolute -273.15  °C


Thanks to Stefan for pointing out error in tau-electron mass ratio.
Values obtained from MilMega table