Understanding Hexadecimal Arithmetic: (and a Tool to Help)

HTML & CSS
1

Hi everyone :waving_hand:,

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.

:1234: 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.

:hammer_and_wrench: What I Built to Help

So I built a free, developer-focused tool:
:backhand_index_pointing_right: HexCalculator.org

It currently supports:

  • :white_check_mark: Hex addition, subtraction, multiplication, division
  • :counterclockwise_arrows_button: Real-time conversions to/from decimal, binary, IP, UTF-8, signed integers
  • :high_voltage: 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.

:speech_balloon: 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 :rocket:

Cheers,
Peter Parker
(Full Stack Dev + Creator of HexCalculator.org)

2

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.

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image291×126 1.74 KB

And if you absolutely need your answer in hex, the toString method of the Number type can do that:
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image606×138 3.4 KB

(For those that cant see pictures on the forum cleanly:

> 0x1F4+0x3B7
< 1451
> (0x1F4+0x3B7).toString(16)
< '5ab'

And that way, I can do any hex math on any website in the world, without needing to go to a different website to do it… that… seems easier?

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