# Converting Decimal to Hex
**URL:** https://discourse.nodered.org/t/converting-decimal-to-hex/47600
**Category:** General
**Created:** [24 June 2021 18:31 UTC](https://discourse.nodered.org/t/converting-decimal-to-hex/47600 "2021-06-24T18:31:06Z")
**Posts on this page:** 9
**Page:** 2
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [26 June 2021 10:21 UTC](https://discourse.nodered.org/t/converting-decimal-to-hex/47600/21 "2021-06-26T10:21:31Z")
```auto
const hexchars = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'];
let val = msg.payload;
let answer = "";
let size = 2;
while (size--) {
answer = hexchars[val & 0xF] + answer;
val = val >> 4;
}
msg.payload = "0x" + answer;
return msg;
```
---
### Author:  [@Apple](https://discourse.nodered.org/u/Apple)
#### Post date: [26 June 2021 10:21 UTC](https://discourse.nodered.org/t/converting-decimal-to-hex/47600/22 "2021-06-26T10:21:34Z")
i see Apologies again 😅
---
### Author:  [@Apple](https://discourse.nodered.org/u/Apple)
#### Post date: [26 June 2021 10:29 UTC](https://discourse.nodered.org/t/converting-decimal-to-hex/47600/23 "2021-06-26T10:29:34Z")
damn you did that pretty fast 😅 Would it be to much to ask you to explain how your code works, if so ill go do the research myself I don't mind was just wondering
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [26 June 2021 10:49 UTC](https://discourse.nodered.org/t/converting-decimal-to-hex/47600/24 "2021-06-26T10:49:21Z")
Upfront info to keep in mind / refer back to...
- `&` is a [Bitwise AND](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Bitwise_AND)
- `& 0xF` means AND the value with 0xf (or decimal 15 or binary `0000 1111`)
- `>>` is a [Sign-propagating right shift](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Right_shift)
- `>> 4` means shift the bits in a number 4 to right - effectively dropping the right most digit & moving other digits in the number to the right
Example of `&`
- `201` in binary is `1100 1001`
- `0xF` in binary is `0000 1111`
- `1100 1001` AND `0000 1111` == `0000 1001` == `9`
#### The routine...
`answer = hexchars[val & 0xF] + answer;`
--- `val & 0xF` gets the 4 bits at the right most side of the value. e.g. `201 & 0xF` --\> 9 (see above info)
`hexchars[val & 0xF]` equals 9
--- then the 9th index in `hexchars` is the character "9" - that is appended to `answer`
`val = val >> 4;`
--- then we shift `val` 4 bits right `val = val >> 4;` to drop the first digit (as it is now processed) e.g. `201 >> 4` == 12
NEXT LOOP...
`answer = hexchars[val & 0xF] + answer;`
--- Now that val is 12, we do `val & 0xF` which == 12
--- 12 == `0000 1100`
--- & 0xF `0000 1111`
--- becomes `0000 1100` (i.e. stays at 12)
The 12th index in `hexchars` is "C" - that is appended to `answer`
The loop is finished so `msg.payload` gets set to `answer` and returned.
---
### Author:  [@Apple](https://discourse.nodered.org/u/Apple)
#### Post date: [26 June 2021 10:54 UTC](https://discourse.nodered.org/t/converting-decimal-to-hex/47600/25 "2021-06-26T10:54:34Z")
Thank you so so much. You helped me so much. And thank you to everyone else that helped. Thank you all and enjoy your day and/or night further 🙂
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### Author:  [@Apple](https://discourse.nodered.org/u/Apple)
#### Post date: [26 June 2021 11:21 UTC](https://discourse.nodered.org/t/converting-decimal-to-hex/47600/26 "2021-06-26T11:21:06Z")
Apologies to come back but with your code @Steve-Mcl i noticed that with your size variable if the answer is anything bigger than 2 it only gives the last 2 values would there be a way to set the size to fit the answers length. i assume you wouldn't be able to do something like answer.length since the answer is being determined. If u use msg.payload.length it'll only set it to 1 since there's only 1 value inside of it
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [26 June 2021 11:24 UTC](https://discourse.nodered.org/t/converting-decimal-to-hex/47600/27 "2021-06-26T11:24:50Z")
I don't follow what you're asking.
The solution is designed to handle 1 byte. If you want to send it 16 bit numbers, set size to 4.
You could have course to this dynamically by testing the value of msg.payload.
E.g...
If msg.payload \> 255, set size to 4
If msg.payload \> 65535, set size to 8
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### Author:  [@Apple](https://discourse.nodered.org/u/Apple)
#### Post date: [26 June 2021 11:28 UTC](https://discourse.nodered.org/t/converting-decimal-to-hex/47600/28 "2021-06-26T11:28:33Z")
I see I see awesome thank you! sorry to bother
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### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [10 July 2021 11:28 UTC](https://discourse.nodered.org/t/converting-decimal-to-hex/47600/29 "2021-07-10T11:28:36Z")
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