About
TAYSTUDIO is a solo-operated site providing 43 free utility tools. All processing in your browser.
Your files stay on your device.
No upload, no signup, no tracking.
TAYSTUDIO is a set of tools a working backend developer built to use himself — which is why the rules for building them are clear.
Your files never leave your browser
Images, PDFs, videos, calculator inputs — all processed only in your browser. Nothing is uploaded to our servers, nothing is stored, and the operator can't see it. Built this way from the start so you can handle IDs, contracts, and salary figures with peace of mind.
No signup, no install, no forced ad tracking
No email asked, no app to install, no login wall. Open the link, use it on the spot, close it. Done.
Not every tool gets built
Building everything that draws traffic turns a site into a mass-produced warehouse. A new tool has to pass five filters — maintainable long-term, trustworthy results, distinct from what exists, still meaningful in two years, fits this site's identity. Cutting candidates is harder than adding them, but that's what separates a “warehouse” from a “curated set”.
Numbers aren't guessed
Tax rates, deductions, legal limits aren't copied from blogs or news — they're verified against primary sources (statutes, official notices, official tables) and cited at the bottom of each calculator. A wrong calculator is worse than none.
TayLee · backend developer (5 years)
A working backend developer, currently learning frontend. Builds and maintains this site in spare time outside the day job, and records what he learns on the blog — so the tools, the writing, and the person are one body of work.
Tech Stack
- Image processing: HTML Canvas API + browser native decoders (WebP, AVIF, HEIC)
- PDF processing: pdf-lib (MIT) WebAssembly + pdf.js (Mozilla, Apache 2.0)
- Video processing: ffmpeg.wasm (LGPL 2.1)
- OCR: Tesseract.js v5 WebAssembly (Apache 2.0)
- QR scanning: jsQR (Apache 2.0)
- HEIC → JPG: heic2any (Mozilla libheif)
- Background removal (AI): img.ly (ONNX Runtime Web)
- EXIF processing: piexifjs (MIT)
- MP3 encoding: libmp3lame (LGPL)
- PWA: Service Worker caching, installable as home screen app
- Analytics: Google Analytics 4 + Cloudflare Web Analytics (anonymous only, no input/file data)
Calculator References
Calculators on the English mirror are based on peer-reviewed formulas and international standards.
- BMI — WHO Asia-Pacific 6-stage classification
- Body Fat — U.S. Navy method (DoD circumference measurements)
- Ideal Weight — Broca, Devine, Robinson, Miller formulas + BMI 22 reference
- BMR / TDEE (Calorie) — Mifflin-St Jeor equation (1990, Am J Clin Nutr)
- Compound Interest — Standard compound interest formula
A = P(1+r/n)^(nt) - Loan — Equal monthly payment (annuity) and equal principal methods
- Savings — Periodic deposit future value formula
- D-day — Gregorian calendar date arithmetic (day/week/month/year units)
Korean-specific calculators (salary, year-end tax, real estate, parental leave) link to Korean government agencies on the Korean about page.
⚠️ All calculations are reference estimates only. Formulas may have edge cases (athletes for BMI, extreme age ranges, etc.). Verify with professionals (doctors, financial advisors) for important decisions. Each tool page has a "References" section at the bottom with detailed sources.
Contact / Feedback
Tool improvement requests, bug reports, and new tool suggestions are welcome via the channels below. No general support desk.
FAQ
Are files uploaded to a server?
No. This site has no backend server. All file processing happens entirely in your browser. The operator cannot see what you process — there is no upload.
Can I trust the calculator results?
Calculator results are reference estimates. Tax rates and rules change yearly, and this site doesn't guarantee yearly updates. For important decisions (tax filing, legal matters), please verify with official sources (NTS, NHIS, KEIC) or professional advisors.
Why do I see ads / no ads?
Ad revenue funds the site. Ad blockers will hide them. Ad placement is tuned to avoid disrupting tool flow.
How to request a new tool?
Email [email protected] with the tool name, use case, and expected behavior. Note: only tools passing the 5-filter criteria are accepted, so not every request will be built.