Dĺžka - premena jednotiek dĺžky

Tabulka premien jednotiek dĺžky
=	fm femtometer	pm pikometer	Å Ångström	nm nanometer	μm mikrometer	mm milimeter	cm centimeter	in palec	dm decimeter	ft stopa	yd yard	m meter	km kilometer	mi míľa	n.m. námorná míľa	lea league	AU astronomická jednotka	ly svetelný rok	pc parsek
1 fm	1	0.001	0.00001	0.000001	0.000000001	0.000000000001	0.0000000000001	0.0000000000000394	0.00000000000001	0.00000000000000328	0.00000000000000109	0.000000000000001	0.000000000000000001	0.000000000000000000621	0.000000000000000000540	0.000000000000000000207	0.00000000000000000000000000668	0.000000000000000000000000000000106	0.0000000000000000000000000000000324
1 pm	1000	1	0.01	0.001	0.000001	0.000000001	0.0000000001	0.0000000000394	0.00000000001	0.00000000000328	0.00000000000109	0.000000000001	0.000000000000001	0.000000000000000621	0.000000000000000540	0.000000000000000207	0.00000000000000000000000668	0.000000000000000000000000000106	0.0000000000000000000000000000324
1 Å	100000	100	1	0.1	0.0001	0.0000001	0.00000001	0.00000000394	0.000000001	0.000000000328	0.000000000109	0.0000000001	0.0000000000001	0.0000000000000621	0.0000000000000540	0.0000000000000207	0.000000000000000000000668	0.0000000000000000000000000106	0.00000000000000000000000000324
1 nm	1000000	1000	10	1	0.001	0.000001	0.0000001	0.0000000394	0.00000001	0.00000000328	0.00000000109	0.000000001	0.000000000001	0.000000000000621	0.000000000000540	0.000000000000207	0.00000000000000000000668	0.000000000000000000000000106	0.0000000000000000000000000324
1 μm	1000000000	1000000	10000	1000	1	0.001	0.0001	0.0000394	0.00001	0.00000328	0.00000109	0.000001	0.000000001	0.000000000621	0.000000000540	0.000000000207	0.00000000000000000668	0.000000000000000000000106	0.0000000000000000000000324
1 mm	1000000000000	1000000000	10000000	1000000	1000	1	0.1	0.0394	0.01	0.00328	0.00109	0.001	0.000001	0.000000621	0.000000540	0.000000207	0.00000000000000668	0.000000000000000000106	0.0000000000000000000324
1 cm	10000000000000	10000000000	100000000	10000000	10000	10	1	0.394	0.1	0.0328	0.0109	0.01	0.00001	0.00000621	0.00000540	0.00000207	0.0000000000000668	0.00000000000000000106	0.000000000000000000324
1 in	25400000000000	25400000000	254000000	25400000	25400	25.4	2.54	1	0.254	0.0833	0.0278	0.0254	0.0000254	0.0000158	0.0000137	0.00000526	0.000000000000170	0.00000000000000000268	0.000000000000000000823
1 dm	100000000000000	100000000000	1000000000	100000000	100000	100	10	3.937	1	0.328	0.109	0.1	0.0001	0.0000621	0.0000540	0.0000207	0.000000000000668	0.0000000000000000106	0.00000000000000000324
1 ft	304800000000000	304800000000	3048000000	304800000	304800	304.8	30.48	12	3.048	1	0.333	0.305	0.000305	0.000189	0.000165	0.0000631	0.00000000000204	0.0000000000000000322	0.00000000000000000988
1 yd	914400000000000	914400000000	9144000000	914400000	914400	914.4	91.44	36	9.144	3	1	0.914	0.000914	0.000568	0.000494	0.000189	0.00000000000611	0.0000000000000000967	0.0000000000000000296
1 m	1000000000000000	1000000000000	10000000000	1000000000	1000000	1000	100	39.370	10	3.281	1.0936	1	0.001	0.000621	0.000540	0.000207	0.00000000000668	0.000000000000000106	0.0000000000000000324
1 km	1000000000000000000	1000000000000000	10000000000000	1000000000000	1000000000	1000000	100000	39370.0787	10000	3280.840	1093.613	1000	1	0.621	0.540	0.207	0.00000000668	0.000000000000106	0.0000000000000324
1 mi	1609344000000000000	1609344000000000	16093440000000	1609344000000	1609344000	1609344	160934.4	63360	16093.44	5280	1760	1609.344	1.609	1	0.869	0.333	0.0000000108	0.000000000000170	0.0000000000000522
1 n.m.	1852000000000000000	1852000000000000	18520000000000	1852000000000	1852000000	1852000	185200	72913.386	18520	6076.115	2025.372	1852	1.852	1.151	1	0.384	0.0000000124	0.000000000000196	0.0000000000000600
1 lea	4828032000000000000	4828032000000000	48280320000000	4828032000000	4828032000	4828032	482803.2	190080	48280.32	15840	5280	4828.032	4.828	3	2.607	1	0.0000000323	0.000000000000510	0.000000000000156
1 AU	149597870700000000000000000	149597870700000000000000	1495978707000000000000	149597870700000000000	149597870700000000	149597870700000	14959787070000	5889679948818.898	1495978707000	490806662401.575	163602220800.525	149597870700	149597870.7	92955807.273	80776388.0670	30985269.0910	1	0.0000158	0.00000485
1 ly	9460700000000000000000000000000	9460700000000000000000000000	94607000000000000000000000	9460700000000000000000000	9460700000000000000000	9460700000000000000	946070000000000000	372468503937007874.0157	94607000000000000	31039041994750656.168	10346347331583552.0560	9460700000000000	9460700000000	5878606438399.745	5108369330453.564	1959535479466.582	63240.873	1	0.307
1 pc	30857000000000000000000000000000	30857000000000000000000000000	308570000000000000000000000	30857000000000000000000000	30857000000000000000000	30857000000000000000	3085700000000000000	1214842519685039370.0787	308570000000000000	101236876640419947.507	33745625546806649.169	30857000000000000	30857000000000	19173650878867.414	16661447084233.261	6391216959622.471	206266.305	3.262	1

Fyzikálna veličina dĺžka má značku l.

Základnou jednotkou dĺžky je meter (m), ten je definovaný ako dĺžka dráhy, ktorú prejde svetlo vo vákuu za 1/299792458 sekundy.

Čiastkovými jednotkami dĺžky sú nanometer (nm, 1mm=0,000 000 001m), mikrometer (μm, 1μm=0,000 001m), milimeter (mm, 1mm=0,001m) a centimeter (cm, 1cm=0,01m). Z násobných jednotiek sa používa kilometer (km, 1km=1000m). Anglického pôvodu sú inch (in, palec, čítajte inč), foot (ft, stopa, čítajte fút), yard (yd, čítajte jard).

Na meranie dĺžky používame dĺžkové meradlá, pravítko, skladací meter, posuvné meradlo, mikrometrickú skrutku a laserové diaľkomery.