I’ve been working a lot with low-level programming and network data lately, and one thing that often slows me down is hexadecimal arithmetic — especially when dealing with large values, signed vs unsigned formats, or needing to verify quick conversions.
Common Hex Arithmetic Scenarios
Here are just a few real-world cases:
Calculating memory offsets or address ranges (e.g., 0x1A3F + 0x0F2B)
Performing subtraction between two addresses or packet sizes
Multiplying or dividing hex values to compute register configurations
Dealing with signed hex where overflow or underflow matters
I realized there’s a lack of clean, reliable in-browser tools that can perform these operations without clutter, ads, or copy-paste overhead.
Real-time conversions to/from decimal, binary, IP, UTF-8, signed integers
Fast and distraction-free interface (no logins, no cookies, no bloat)
Example:
Input: 0x1F4 + 0x3B7 → Output: 0x5AB
With signed representation and all conversions displayed side-by-side.
What I’d Love to Know:
Do you often run into hex arithmetic needs in your workflow?
How do you currently handle those (code, CLI, calculator)?
What features would be useful in a tool like this?
Happy to hear feedback, suggestions, or just general experiences working with hex in dev or hardware projects. And if you want to give the tool a spin, it’s live here: https://hexcalculator.org
Never? (Note, i’m not saying there arent people who do need this, but i’ve never needed to do more than converting a hex to a 1-255 int or vice versa in my web development career.)
Well, despite you saying there’s a lack of in-browser tools that can perform these operations… that’s… not true.
The javascript console, accessible by hitting F12, is fully capable of doing hexidecimal math.
When I was doing data conversions from random binary-format files into text, I ran into all sorts of interesting ways of storing stuff like dates, record pointers and the like, and the need for hex arithmetic was frequent. Fortunately, however, I was doing that on a multi-user OS that, among other things in the command line interpreter, had exactly this kind of thing built in.
I expect Powershell has it too now, but it didn’t in the late 1980s.I didn’t know it could be done from a browser console, so that might come in handy.
Interesting the different ways people solve issues - if I needed to do hex sums now, I’d probably just fire up the VM and do it as above
const toDec = (x) => parseInt(x, 16);
const toHex = (x) => x.toString(16);
/* lookup operations */
const operations = {
'+': (x, y) => x + y,
'-': (x, y) => x - y,
'*': (x, y) => x * y,
'/': (x, y) => x / y
};
function displayResult (result, formElements) {
const { outputDecimal, outputHex } = formElements;
outputDecimal.value = result;
outputHex.value = toHex(result);
}
window.addEventListener('DOMContentLoaded', () => {
const form = document.querySelector('#calculator');
form.addEventListener('submit', (event) => {
event.preventDefault();
// create an object from form data
// e.g. { input1: 'f', input2: 'a', operation: '+' }
const { input1, input2, operation } = Object.fromEntries(new FormData(form));
// Check if we have a matching operation function in lookup operations
if (typeof operations[operation] === 'function') {
const result = operations[operation](toDec(input1), toDec(input2));
displayResult(result, form.elements);
}
});
});
If you wrap your inputs in a form, not only do you have access to the form elements by name, but there is also no need for a reset function, as it is built in e.g. <button type='reset'>
In addition you can add pattern to your inputs to prevent nonsensical inputs
Note, mine doesn’t check for division by zero, and I am sure there are other checks that could be added.
,
Common Hex Arithmetic Scenarios
What I Built to Help
Hex addition, subtraction, multiplication, division
Real-time conversions to/from decimal, binary, IP, UTF-8, signed integers
Fast and distraction-free interface (no logins, no cookies, no bloat)
What I’d Love to Know:
