Frequently Asked Questions

SDK.bz is a free, browser-based suite of calculators. Each calculator runs entirely in your browser — there is no server-side execution, no upload, no waiting on a remote service to process your data.

It is free, and there is no paid tier. We are funded by display advertising. We have no plans to introduce a "Pro" plan, paywalls, or content gates.

No. Every calculator works without an account. There is no sign-up flow, no e-mail collection, and no password.

Any modern desktop or mobile browser (Chrome 90+, Firefox 90+, Safari 15+, Edge 90+). The site is mobile-first and works well on phones and tablets.

Static pages cache after the first load, so a previously visited calculator will render with a flaky connection. The calculators themselves do not require the network because computation happens in your browser.

No. We rely on the browser as the cross-platform runtime. Adding the site to your home screen on iOS or Android gives you something close to an app.

Open your browser settings, find "site data" or "storage" for our domain, and clear it. All preferences are stored exclusively in your browser localStorage.

E-mail us with [BUG] in the subject line, the URL of the page, the inputs you used, the result you got, and what you expected. Reproduction details get the fastest fix.

E-mail us with [FEATURE] in the subject line. A one- or two-sentence description of the use-case beats a one-word request by a wide margin.

Because computation happens in your browser instead of on a remote server. We also pre-render and cache aggressively at Cloudflare's edge, so the HTML reaches you in under 100 ms in most countries.

Ads pay the entire bill: hosting, the writing of guides, translation review, and the small team behind the site. Without them, the free version of the site does not exist. We try to keep ad density well below the industry average.

Yes. The first time you visit from the EU, the UK, or Korea you will see a Google-managed consent banner where you can refuse personalised advertising. You can also visit https://adssettings.google.com at any time to change those preferences globally for any Google-served ad.

Occasionally, yes — but only when the sponsor's offer fits the audience and we can mark the sponsorship clearly. We will never disguise sponsored content as a regular calculator or guide.

No. Every input you put into a calculator stays in your browser. The text, numbers, files, or images you provide never reach our servers.

Standard, aggregated analytics: page URL, referrer, country derived from a truncated IP, browser family, OS, screen size, language preference, and ad-related events. IP addresses are anonymised before storage. Full details are in our Privacy Policy.

No. We do not sell, rent, or share personal data. We share the minimum needed with our infrastructure providers (Cloudflare, Google for analytics and ads) under written agreements that limit use to operating the service.

For data in your browser, clear the site's storage. For e-mail correspondence, write to contact@sdk.bz with [LEGAL] in the subject and we will process the deletion within the timeframes required by GDPR (usually 30 days) or PIPA (usually 10 days).

We deploy to Cloudflare Pages, which serves traffic from a global edge network. Static assets and request handling happen at the edge node closest to you.

SvelteKit and TypeScript on the front, Tailwind CSS for styling, and Cloudflare Pages plus Workers for hosting and any edge logic. There is no traditional backend; we lean on the browser and the edge.

Parts of it are public on GitHub. The full site code is not currently open source, primarily to maintain our content quality bar across translations and product surfaces.

Every formula in our calculators is documented either in the guide page or in inline tooltips. We re-derive each formula from primary sources and cross-check against trusted reference implementations. If you spot a discrepancy, please report it via [BUG].

We test with keyboard-only navigation, screen-reader walkthroughs of the main flows, and aim for WCAG 2.2 AA conformance on long-form content.

Yes. UI strings, calculators, guides, and legal pages are all available in English, Korean, Japanese, and Chinese. Translations are reviewed by native speakers, not produced by a one-shot machine pass.

SDK.bz is operated by SDK Co., Ltd., a Korean software company (business registration 871-81-03242). Operator details and contact info are on our About and Contact pages.

No. Our calculators provide informational estimates only. They are not financial, legal, medical, or other professional advice. Talk to a qualified professional for decisions that materially affect your life.

Absolutely. Linking to calculators and guides is encouraged. We just ask that you do not screenshot the entire page and re-host it as your own.