Unit is representation of any of any physical parameter with its magnitude. Engineers and scientists mainly use much numbers of units. There are several unit systems as like metric, British and so on. Every engineer have to know about the conversion factors of units that used in your daily life.
As like for example, which unit you prefer to express the room size of your house? meter or feet? i mostly prefer feet so i can imagine the size. If some one said me room size is X meter then i just calculate easily multiply it 3.28 tentatively and set the size of room in mind. Its just one type of habit even i mostly use "m" as unit of measurement in other cases.
Here i collected some engineering unit conversion factors, that might be useful for you. take a look at these followings.....
You can also share your ideas on using of units.
Basic Units
| Length | meter | m |
| Time | second | s |
| Mass | kilogram | kg |
| Temperature | Kelvin | K |
| Electrical Current | ampere | A |
Derived Units
| Force | Newton | N | kg m s-2 |
| Energy | joule | J | kg m2 s-2 |
| Power | watt | W | kg m2 s-3 |
| Frequency | hertz | Hz | s-1 |
| Charge | coulomb | C | A s |
| Capacitance | farad | F | C2 s2 kg-1 m-2 |
| Magnetic Induction | tesla | T | kg A-1 s-2 |
Multiples of Ten
| 10-12 | pico | p |
| 10-9 | nano | n |
| 10-6 | micro | µ |
| 10-3 | milli | m |
| 103 | kilo | k |
| 106 | mega | M |
| 109 | giga | G |
| 1012 | tera | T |
Coefficients to change units in engineering.
| To Convert | To | Multiply By |
| acres | ft2 | 43560 |
| acres | m2 | 4046.9 |
| acres | rods2 | 160 |
| acres | hectares | .4047 |
| acre feet | barrels | 7758 |
| acre feet | m3 | 1233.5 |
| angstrom, å | cm | 10-8 |
| angstrom, å | nm | 0.1 |
| astronomical unit, AU | cm | 1.496E13 |
| astronomical unit | Tm | 0.1496 |
| atmospheres (atm) | feet of water | 33.94 |
| atmospheres | in of Hg | 29.92 |
| atmospheres | mm of Hg | 760 |
| atmospheres | psi | 14.7 |
| bar | atm | .98692 |
| bar | dyne cm-2 | 106 |
| bar | psi (lb in-2) | 14.5038 |
| bar | mm Hg | 750.06 |
| bar | MPa | 10-1 |
| barrel (bbl) | ft3 | 5.6146 |
| barrel | m3 | .15898 |
| barrel | gal (US) | 42 |
| barrel | liter | 158.9 |
| BTU | Canadian BTU | 1.000418022 |
| BTU | ISO BTU | 1.000527124 |
| BTU | cal | 251.996 |
| BTU | erg | 1.055055853 * 1010 |
| BTU | joule | 1054.35 |
| calorie (gm) (cal) | joule | 4.184 |
| centimeter (cm) | inch | 0.39370 |
| cm | m | 10-2 |
| darcy | m2 | 9.8697E-13 |
| dyne | g cm s-2 | 1 |
| dyne | Newton | 10-5 |
| erg | cal | 2.39006E-8 |
| erg | dyne cm | 1 |
| erg | joule | 10-7 |
| fathom (fath) | ft | 6 |
| feet (ft) | in | 12 |
| feet | m | 0.3048 |
| furlong | yd | 220 |
| gallon (US) (gal) | in3 | 231 |
| gallon | liter | 3.78541 |
| gallon (Imp.) (gal) | in3 | 277.419 |
| gallon | liter | 4.54608 |
| gamma | gauss | 10-5 |
| gamma | tesla | 10-9 |
| gauss | tesla | 10-4 |
| gram (g) | pound | 0.0022046 |
| gram | kg | 10-3 |
| hectare | acre | 2.47105 |
| hectare | cm2 | 108 |
| horsepower | W | 745.700 |
| inch (in) | cm | 2.54 |
| inch (in) | mm | 25.4 |
| joule (J) | erg | 107 |
| joule | cal | 0.239006 |
| kilogram (kg) | g | 103 |
| kilogram | pound | 2.20462 |
| kilometer (km) | m | 103 |
| kilometer | ft | 3280.84 |
| kilometer | mile | 0.621371 |
| kilometer hr-1 (kph) | mile hr-1 (mph) | 0.621371 |
| kilowatt | hp | 1.34102 |
| knot | mph | 1.150779 |
| liter | cm3 | 103 |
| liter | gal (US) | 0.26417 |
| liter | in3 | 61.0237 |
| meter | angstrom | 1 x 1010 |
| meter | ft | 3.28084 |
| micron | cm | 10-4 |
| mile | ft | 5280 |
| mile | km | 1.60934 |
| mm Hg | dyne cm-2 | 1333.22 |
| Newton | dyne | 105 |
| Newton | pound (lbf) | 0.224809 |
| Newton-meter (torque) | foot-pound-force | .737562 |
| ounce | lb | 0.0625 |
| Pascal | atmospheres | 9.86923 * 10-6 |
| Pascal | psi | 1.45 * 10-4 |
| Pascal | torr | 7.501 * 10-3 |
| pint | gallon | 0.125 |
| poise | g cm-1 s-1 | 1 |
| poise | kg m-1 s-1 | 0.1 |
| pound (lbm) | kg | 0.453592 |
| pound (lbf) | newton | 4.4475 |
| rod | feet | 16.5 |
| quart | gallon | 0.25 |
| stoke | cm2 s-1 | 1 |
| slug | kg | 14.594 |
| tesla | gauss | 104 |
| Torr | Millibar | 1.333224 |
| Torr | Millimeter of Hg | 1 |
| ton (long) | lb | 2240 |
| ton (Metric) | lb | 2205 |
| ton (Metric) | kg | 1000 |
| ton (short or net) | lb | 2000 |
| ton (short or net) | kg | 907.185 |
| ton (short or net) | ton (Metric) | .907 |
| watt | J s-1 | 1 |
| yard | in | 36 |
| yard | m | 0.9144 |
| year (cal) | days | 365.242198781 |
| year (cal) | s | 3.15576 x 107 |
METRIC
| 1 km = 10 hm 1 km = 1000 m 1 hm = 100 m 1 m = 10 dm 1 dm = 10 cm 1 cm = 10 mm | 1 km2 = 100 hectares 1 hectare = 100 ares 1 are = 100 m2 1 m2 = 100 dm2 1 dm2 = 100 cm2 1 cm2 = 100 mm2 | 1 m3 = 1000 litres 1 litre = 1 dm3 1 litre = 1000 cc 1 litre = 1000 ml | 1 tonne = 1000 kg 1 kg = 1000 g 1 g = 1000 mg |
IMPERIAL to METRIC
| 1 mile = 1.609 km 1 yard = 0.9144 m 1 foot = 0.3048 m 1 inch = 25.4 mm | 1 sq. mile = 2.59 km2 1 acre = 0.4047 hectares 1 acre = 4046.86 m2 1 sq. yard = 0.8361 m2 1 sq. foot = 0.0929 m2 1 sq. inch = 645.16 mm2 | 1 gallon = 4.5461 litres 1 US gallon = 3.785 litres 1 pint = 0.5683 litres 1 cu. inch = 16.3871 cm3 | 1 ton = 1.016 tonnes 1 lb. = 0.4536 kg 1 oz. = 28.3495 g 1 US ton = 0.9072 tonnes |
METRIC to IMPERIAL
| 1 km = 0.54 miles 1 m = 1.0936 yards 1 m = 3.2808 feet 1 mm = 0.0394 inches | 1 km2 = 0.3861 mile2 1 km2 = 247.105 acres 1 hectares = 2.4711 acres 1 m2 = 10.7639 feet2 1 mm2 = 0.0016 inches2 | 1 litre = 0.22 gal. 1litre = 0.2642 US gal. 1 litre = 1.7598 pint 1 m3 = 219.969 gal. 1 m3 = 35.3147 feet3 | 1 tonne = 0.9842 ton 1 tonne = 1.1023 US ton 1 kg = 2.2046 lb. 1 kg = 35.274 oz. |
TEMPERATURE
| deg. C x 9/5 + 32 = deg. F | (deg. F - 32) x 5/9 = deg. C |
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