40px to rem = 2.5rem
40 pixels equals 2.5rem at the default root font size of 16px. Adjust the root size below to recalculate.
px
px
2.5rem
How it works
To convert 40px to rem, divide by the root font size: 40 / 16 = 2.5. The rem unit is relative to the root element’s font size, which browsers default to 16px.