Does my data get uploaded anywhere?
No. Everything runs locally in your browser and nothing is sent to a server.
Is this free to use?
Yes. It is completely free, with no account, no signup, and no usage limits.
Does it work on a phone?
Yes. The page runs in any modern mobile browser, on iPhone and Android alike, with no app to install.
How do I convert 5 ft 9 in to meters?
Turn the compound measurement into a single number first. 9 in is 0.75 ft, so enter 5.75 ft and select meters, which gives 1.7526 m exactly. The converter takes one value in one unit, it does not parse feet and inches together.
Why does 1 m show as 3.28083989501 ft instead of 3.28 ft?
The display keeps 12 significant figures for values of 1 and above, so you can round to whatever precision your work needs. 3.28 ft is a 0.03% error, which is fine for a room and not fine for a machined part.
Is a nautical mile the same as a mile?
No. A nautical mile is 1852 m and a statute mile is 1609.344 m, so the nautical mile is 15.08% longer. Both are in the unit list, and mixing them is the most common error in marine and aviation numbers.
How exact are the imperial factors used here?
They are exact by definition. The 1959 international yard and pound agreement fixed the yard at exactly 0.9144 m, which makes the foot 0.3048 m and the inch 0.0254 m with no residual error. Every imperial factor in this tool derives from those definitions.
How do I get a screen size in centimeters?
Screen sizes are diagonals, so a 15.6 in laptop is a 39.624 cm diagonal, not a 39.624 cm width. Enter 15.6 in and read the centimeter row, then use the aspect ratio to get width and height if you need them.
What unit does the converter use internally?
The meter. Every unit declares a factor to meters, your value is converted to meters, and every other unit is derived from that single base value. That is why the whole table stays consistent no matter which pair you pick.