What is the difference between make and new in golang
Jul 06, 2025 am 02:09 AMIn Go, new is used to allocate memory for a value and returns a pointer to the zero value of that type, while make initializes slices, maps, or channels and returns a usable value. 1. new(T) allocates memory for type T and returns a *T pointer to a zeroed value, applicable for any type including structs and basic types. 2. make is specific to slices, maps, and channels, returning initialized values ready for use, not pointers. 3. Use new when needing a pointer to a zeroed instance, and make when creating built-in reference types with internal state. 4. Misusing uninitialized maps or slices without make leads to runtime errors, highlighting the importance of choosing between new and make based on type and usage needs.
In Go, the difference between make
and new
can be a bit confusing at first, especially when you're just getting started. Both are used for allocating memory, but they serve different purposes and return different types of values.

Here's what you need to know:

What new does in Go
new(T)
is used to allocate memory for a value of type T
. It returns a pointer to the zero value of that type.
For example:

p := new(int)
This line creates an int
variable with the default value 0
, and returns a pointer pointing to it. So now p
is of type *int
.
- You'll mostly use
new
when you want a pointer to a zeroed-out value. - It works for any type — basic types like
int
, structs, etc. - The result is always a pointer (
*T
), even if the type itself is large.
A common case might look like:
type User struct { Name string } u := new(User)
Now u
is a pointer to a User
struct with all fields set to their zero values (like empty strings, zeros, or nils).
What make does in Go
make
is specifically used for initializing slices, maps, and channels. These types are not just simple data structures — they have internal state and behavior that needs setup beyond just memory allocation.
So unlike new
, make
doesn't return a pointer; it returns a ready-to-use value of the specified type.
Examples:
s := make([]int, 0, 5) // slice with length 0, capacity 5 m := make(map[string]int) // map ready to use c := make(chan int) // unbuffered channel
You can’t use new
for these types because they need more than just allocated memory — they require initialization logic that only make
provides.
Key points:
- Only use
make
for slices, maps, and channels. - Returns initialized values, not pointers.
- Sets up internal structure so you can start using them immediately.
When to choose one over the other
Here’s a quick breakdown of when to use each:
Use
new
when:- You want a pointer to a zeroed instance of a type.
- Working with structs or basic types where you need indirection.
Use
make
when:- Initializing slices, maps, or channels.
- Needing the actual usable value, not just memory space.
It’s easy to remember:
? new
is for general-purpose pointer allocation.
? make
is for creating usable instances of built-in reference types.
One thing people often miss
Sometimes people try to do something like this:
var m map[string]int m["key"] = "value"
That will panic because m
is nil
. Instead, you must initialize it with make
before use.
Similarly, if you do:
s := []int{} s[0] = 1
That also panics because the slice is empty. You'd need to use make
to pre-allocate space:
s := make([]int, 1) s[0] = 1
These small gotchas show why understanding how make
and new
work under the hood is important.
So yeah, new
gives you pointers, make
gives you initialized built-in types. They’re both useful, just for different jobs.
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