How to Round a Float in Go

Boot.dev Blog » Golang » How to Round a Float in Go
Lane Wagner
Lane Wagner Boot.dev co-founder and backend engineer

Last published November 13, 2022

If you’re rounding a floating point number in Go, it’s most likely you want to format it in a string. Use the built-in fmt.Sprintf() function.

heightInMeters := 1.76234
msg := fmt.Sprintf("Your height is: %.3f", heightInMeters)
// msg = "Your height is: 1.762"

Round float and store in a float

Use math.Floor, math.Round and math.Ceil from the standard math package.

heightInMeters := 1.76234
roundedDown := math.Floor(x*100)/100 // 1.0
roundedToNearest := math.Round(x*100)/100 // 2.0
roundedUp := math.Ceil(x*100)/100 // 2.0

Round float and store in an int

To store the result as an int, use the same method as before and then cast the result.

heightInMeters := 1.76234
roundedToNearest := int(math.Round(x*100)/100) // 2

PS: I’ve got a fully interactive Golang course here if you’re interested in learning more about Go. It’s free to start!

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