# Unitful one(T) = 1.0 (without units). What is the alternative?
**URL:** https://discourse.julialang.org/t/unitful-one-t-1-0-without-units-what-is-the-alternative/71024
**Category:** General Usage
**Tags:** unitful
**Created:** [November 5, 2021, 7:14pm UTC](https://discourse.julialang.org/t/unitful-one-t-1-0-without-units-what-is-the-alternative/71024 "2021-11-05T19:14:09Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@lmiq](https://discourse.julialang.org/u/lmiq)
#### Post date: [November 5, 2021, 7:14pm UTC](https://discourse.julialang.org/t/unitful-one-t-1-0-without-units-what-is-the-alternative/71024/1 "2021-11-05T19:14:09Z")
Basically:
```julia
julia> using Unitful
julia> x = 1.0u"nm"
1.0 nm
julia> zero(typeof(x))
0.0 nm
julia> one(typeof(x))
1.0
julia>
```
Why `one(typeof(x))` is not `1.0 nm`? And which is the alternative to using `one` for unit propagation if one has to do something like
```julia
julia> f(x::T) = x + one(T)/2
f (generic function with 1 method)
julia> f(1.0u"nm")
ERROR: DimensionError: 1.0 nm and 0.5 are not dimensionally compatible.
Stacktrace:
```
edit:
`T(0.5)` is the alternative.
If anyone has further comments, please let me know.
---
### Author:  [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)
#### Post date: [November 5, 2021, 7:19pm UTC](https://discourse.julialang.org/t/unitful-one-t-1-0-without-units-what-is-the-alternative/71024/2 "2021-11-05T19:19:01Z")
```julia
julia> oneunit(typeof(x))
1.0 nm
```
`one` is defined as the multiplicative identity which wouldn’t be true if it was unitful.
---
### Author:  [@stevengj](https://discourse.julialang.org/u/stevengj)
#### Post date: [February 21, 2022, 2:16pm UTC](https://discourse.julialang.org/t/unitful-one-t-1-0-without-units-what-is-the-alternative/71024/3 "2022-02-21T14:16:21Z")
2 posts were split to a new topic: [Zero and zerounit, analogous to one and oneunit?](https://discourse.julialang.org/t/zero-and-zerounit-analogous-to-one-and-oneunit/76841)