# Can I cast a scalar float64 to float32 in Numba?

**URL:** <https://numba.discourse.group/t/can-i-cast-a-scalar-float64-to-float32-in-numba/2998>\
**Category:** Support: How do I do ...?\
**Created:** [May 20, 2025, 12:52pm UTC](https://numba.discourse.group/t/can-i-cast-a-scalar-float64-to-float32-in-numba/2998 "2025-05-20T12:52:56Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![ricardoV94](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/ricardov94/32/1215_2.png) [@ricardoV94](https://numba.discourse.group/u/ricardoV94)\
**Post date:** [May 20, 2025, 12:52pm UTC](https://numba.discourse.group/t/can-i-cast-a-scalar-float64-to-float32-in-numba/2998/1 "2025-05-20T12:52:56Z")

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```python
import numba

@numba.njit
def foo(x):
    return np.float32(x)

x = np.float64(0.0)
type(foo(x)) # float

```

The `.astype` attribute is not available, and the jitted function does nothing either. The only thing I managed is to convert between integers and floats, but not to specify the precision

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**Author:** ![nelson2005](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/nelson2005/32/47_2.png) [@nelson2005](https://numba.discourse.group/u/nelson2005)\
**Post date:** [May 20, 2025, 2:48pm UTC](https://numba.discourse.group/t/can-i-cast-a-scalar-float64-to-float32-in-numba/2998/2 "2025-05-20T14:48:56Z")

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The function does indeed return a float32. It’s being automatically converted to a Python float.

If you print the function nopython\_signatures you’ll see the return type is float32

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<div class="post-metadata">

**Author:** ![ricardoV94](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/ricardov94/32/1215_2.png) [@ricardoV94](https://numba.discourse.group/u/ricardoV94)\
**Post date:** [May 21, 2025, 9:28am UTC](https://numba.discourse.group/t/can-i-cast-a-scalar-float64-to-float32-in-numba/2998/3 "2025-05-21T09:28:18Z")

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I see. Is there a fundamental reason why numba cannot / is not returning numpy scalars?

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**Author:** ![gmarkall](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/gmarkall/32/42_2.png) [@gmarkall](https://numba.discourse.group/u/gmarkall)\
**Post date:** [May 22, 2025, 2:26pm UTC](https://numba.discourse.group/t/can-i-cast-a-scalar-float64-to-float32-in-numba/2998/4 "2025-05-22T14:26:07Z")

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Unfortunately the distinction between NumPy and Python scalars in Numba is a bit fuzzy, and this is one instance of that general treatment.