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Free Length Converter

Method 3 · Scientific & Specialized

From atoms to galaxies.

Convert between subatomic, astronomical, and specialized length units. Scientific notation output for extreme scales.

To

Key conversions.

Angstroms to nanometers

1 Å = 0.1 nm

Light-years to kilometers

1 ly = 9.46073e+12 km

AU to kilometers

1 au = 149597870.7 km

Parsecs to light-years

1 pc = 3.26156377694 ly

Planck length to femtometers

1 lₚ = 1.616255e-20 fm

Points to millimeters

1 pt = 0.352777777778 mm

Scientific unit reference.

26 specialized units with exact conversion factors to meters.

UnitSymbolMeters
Planck Lengthlₚ1.616255e-35
Attometeram1e-18
Femtometerfm1e-15
Picometerpm1e-12
Nanometernm1e-9
AngstromÅ1e-10
Micrometerμm0.000001
MegameterMm1000000
GigameterGm1000000000
ExameterEm1000000000000000000
Microinchμin2.54e-8
Mil (Thou)mil0.0000254
Bohr Radiusa₀5.29177210903e-11
X-unitxu1.00208e-13
Pointpt0.00035277777777777776
Picapc0.004233333333333333
Twiptwip0.00001763888888888889
Light-secondls299792458
Light-minutelm17987547480
Light-hourlh1079252848800
Light-dayld25902068371200
Astronomical Unitau149597870700
Light-yearly9460730472580800
Parsecpc30856775812800000
Kiloparseckpc30856775812800000000
MegaparsecMpc3.08567758128e+22

Swipe horizontally to see all columns

Light-years to kilometers reference table.

Light-year (ly)Kilometer (km)
19.46073e+12
21.892146e+13
32.838219e+13
43.784292e+13
54.730365e+13
65.676438e+13
76.622511e+13
87.568584e+13
98.514657e+13
109.46073e+13
111.04068e+14
121.135288e+14
131.229895e+14
141.324502e+14
151.41911e+14
161.513717e+14
171.608324e+14
181.702931e+14
191.797539e+14
201.892146e+14

Frequently asked questions.

What is an angstrom used for?
An angstrom (0.1 nm) measures atomic and molecular distances in chemistry and physics.
How long is a light-year?
One light-year is about 9.461×10¹⁵ meters — the distance light travels in one Julian year.
What is the difference between AU and light-year?
An astronomical unit (AU) is the mean Earth-Sun distance (~149.6 million km). A light-year is about 63,241 AU.
Can I convert Planck lengths?
Yes. The scientific converter supports Planck length and other subatomic scale units with scientific notation output.