Free · Length & area
Length & Distance Unit Converter
Calculate length converter with editable inputs, reverse calculations, and unit choices.
- Formula & worked example
- Private in your browser
- No signup
Your calculation
Enter enough known values to calculate the blanks.
How to use this calculator
- Enter the values you know in the units shown. Leave unknown values blank.
- Results update automatically as you type. Edit a result to calculate another value, or lock a value to keep it fixed.
- Reset restores the starting fields. A worked example appears below.
Private by default
Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.
Formula and method
Enter the values you know and leave unknown values blank. The equations below calculate the remaining values, including reverse calculations where enough inputs are available.
base = value × source factor + source offset; result = (base − destination offset) ÷ destination factor
Worked example
Enter these known values and leave the other values blank.
- Length in meters
- 1 m
- Length in millimeters
- 1000 mm
- Length in centimeters
- 100 cm
- Length in kilometers
- 0.001 km
- Length in other metric units
- 1 m
- Length in inches
- 39.37 in
- Length in feet
- 3.281 ft
- Length in yards
- 1.0936 yd
- Length in miles
- 0.0006214 mi
- Length in other imperial units
- 3.281 ft
- Length in nautical miles
- 0.00054 nmi
- Length in Sun radii
- 1.4374e-9 R☉
- Length in light years
- 1.057e-16 ly
- Length in other units
- 0.00054 nmi
Assumptions and limitations
- Inputs must satisfy the validation rules. Editing a result can recalculate an earlier input; lock values you want to keep fixed.
Common questions
Can I calculate a different unknown?
Yes. Clear that field and enter the other known values. The calculator uses the available inverse equations.
References
The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.