Every calculator on this page runs entirely in your browser. There's no server round-trip, no API call, and no data sent anywhere — the maths happens on your device, from the numbers you type in, using the exact same calculation functions whether you're looking at the tool page or reading a worked example in a blog post.
The ABV / Attenuation calculator is the flagship: enter your original and final gravity readings and it computes ABV by both the simple formula most homebrewers learned first and the more accurate advanced formula, side by side, plus apparent and real attenuation and an estimated calorie count. The IBU calculator takes a full hop schedule — variety, alpha acid, weight and boil time for each addition — and computes total bitterness by both the Tinseth and Rager formulas, because they routinely disagree and knowing that in advance beats trusting a single number blindly.
The priming sugar calculator corrects for CO2 already dissolved in your beer at whatever temperature it's been sitting at, not just the target you're aiming for, and flags when a target carbonation level crosses the safety ceiling most references treat as the limit for standard bottles. The dilution and blending calculator handles two related but different jobs — watering down an overly strong batch to a target gravity, or blending two batches of different strength to land on a target — using the same gravity-points arithmetic either way. The strike water calculator uses the standard published mash-temperature formula to tell you exactly how hot your strike water needs to be and how much of it you need, given your grain weight, its starting temperature, and your target mash temperature. The SRM colour calculator estimates your beer's colour from your actual grain bill and renders it as a real swatch, so you can see roughly what you're brewing before it's even mashed.
Every tool reads its inputs from the page's URL and writes them back as you change them, so the exact result you're looking at can be bookmarked, copied, or shared with a link — reload the page and you'll see the same numbers, not a blank form.