| Constant | Value | Units | Usage |
|---|---|---|---|
| amu or m | 1.660538782 × 10-27 | kg | atomic mass unit |
| NA or nAv | 6.02214179 × 1023 | mol-1 | Avogadro's number |
| k or kB | 1.3806504 × 10-23 | J/K | Boltzmann's constant |
| C | 6.241509629 × 1018 | e | Coulomb's constant |
| e or q | 1.602176487 × 10-19 | C | elementary charge |
| me | 9.10938215 × 10-31 | kg | elementary mass of an electron |
| me | 5.48579909 × 10-4 | amu | elementary mass of an electron |
| mn | 1.674927211 × 10-27 | kg | elementary mass of a neutron |
| mn | 1.008664916 | amu | elementary mass of a neutron |
| mp | 1.672621637 × 10-27 | kg | elementary mass of a proton |
| mp | 1.007276467 | amu | elementary mass of a proton |
| F | 9.64853399 × 104 | C/mol | Faraday's constant |
| R | 8.314472 | J/mol·K | gas constant |
| R | 0.08205746 | L·atm/mol·K | gas constant |
| Kw | 1.01 × 10-14 | ion-product constant for water at 25°C | |
| 0.0592 | V | Nernst factor at 25°C | |
| h | 6.62606896 × 10-34 | J·s | Planck's constant |
| R∞ | 1.096776 × 107 | m-1 | Rydberg constant |
| c | 2.99792458 × 108 | m/s | speed of light |
| g0 | 9.80665 | m/s2 | standard gravity |
| Energy | ||||
|---|---|---|---|---|
| 1 | cal | = | 4.184 | J |
| 1 | eV | = | 1.602 × 10-19 | J |
| 1 | L·atm | = | 101.325 | J |
| 1 | Btu | = | 1055 | J |
| Length | ||||
| 1 | mi | = | 1760 | yd |
| 1 | mi | = | 5280 | ft |
| 1 | yd | = | 3 | ft |
| 1 | ft | = | 12 | in |
| 1 | m | = | 1.0936 | yd |
| 1 | mi | = | 1.6093 | km |
| 1 | in | = | 2.54 | cm |
| 1 | Å | = | 10-10 | m |
| Mass | ||||
| 1 | lb | = | 453.59 | g |
| 1 | kg | = | 2.2046 | lb |
| 1 | lb | = | 16 | oz |
| 1 | ton | = | 2000 | lb |
| 1 | metric ton (t) | = | 103 | kg |
| Pressure | ||||
| 1 | atm | = | 1.01325 × 105 | Pa |
| 1 | atm | = | 1.01325 | bar |
| 1 | atm | = | 760 | mmHg |
| 1 | atm | = | 760 | torr |
| 1 | atm | = | 14.70 | lb/in2 (psi) |
| 1 | bar | = | 105 | Pa |
| 1 | Pa | = | 1 | N/m2 |
| Radioactivity | ||||
| 1 | Ci | = | 3.7 × 1010 | Bq |
| Temperature | ||||
| 0 | K | = | -273.15 | °C |
| 0 | °C | = | 273.15 | K |
| 0 | K | = | -459.67 | °F |
| tf | °F | = | 5/9(tf – 32) | °C |
| tc | °C | = | 9/5(tc) + 32 | °F |
| Time | ||||
| 1 | calendar year | = | 365 | d |
| 1 | solar year | = | 365.242 | d |
| Volume | ||||
| 1 | L | = | 1.0567 | qt |
| 1 | gal | = | 3.7854 | L |
| 1 | gal | = | 4 | qt |
| 1 | qt | = | 2 | pt |
| 1 | pt | = | 16 | fl. oz. |
| 1 | gal | = | 231 | in3 |
| 1 | cm3 | = | 1 | mL |
| 1 | m3 | = | 103 | L |
| π | = | 3.14159265359 |
| e | = | 2.71828182846 |
| ln(2) | = | 0.69314718056 |
| ln(10) | = | 2.30258509299 |
| STP | (Standard Temperature and Pressure) | = | 0°C and 1 atm |
| SATP | (Standard Ambient Temperature and Pressure) | = | 25°C and 1 atm |
| TSS | (Thermodynamic Standard State) | = | 25°C, 1 atm, 1 M |