# Promise.resolve vs new Promise: When Should You Use What?

Most developers get stuck comparing `Promise.resolve` and `new Promise`, trying to understand the *difference*.

* * *

### Why This Confusion Happens

In simple cases, both approaches behave the same:

```javascript
Promise.resolve("Hello");

new Promise((resolve) => resolve("Hello"));
```

*   Both return a resolved Promise
    
*   Both can be used with `.then()` or `await`
    

* * *

### Rule of Thumb

*   Use `Promise.resolve` when you already have the result
    
*   Use `new Promise` when you need to create async behavior
    

That’s it. Now let’s expand with real examples.

* * *

### When to Use `Promise.resolve`

**1\. When You Already Have a Value**

```javascript
function getData() {
  return Promise.resolve(42);
}
```

*   You’re not doing anything async
    
*   Just wrapping a value in a Promise
    

* * *

### When to Use `new Promise`

**1\. When You Need Async Control (Most Important)**

```javascript
function delay(ms) {
  return new Promise((resolve) => {
    setTimeout(resolve, ms);
  });
}
```

You decide *when* to resolve

* * *

### Quick Comparison (Use Case Based)

| Situation | What to Use |
| --- | --- |
| Already have value | `Promise.resolve` |
| Just wrapping result | `Promise.resolve` |
| Need delay / timer | `new Promise` |
| API / callback conversion | `new Promise` |
| Need manual resolve/reject | `new Promise` |