About SJ AI Studio

SJ AI Studio provides free, high-quality online tools and calculators for everyone. Our mission is to make useful tools accessible to all — no sign-ups, no fees, no downloads required.

Our Mission

We believe everyone deserves access to useful tools without barriers. Whether you are working out the acquisition tax on an apartment, checking how much stain a fence needs, or reading last week’s lottery draw — the answer should take one page and no sign-up.

What We Offer

Sixty tools, grouped the way people actually arrive at them:

• Korean finance and tax (19) — 취득세, 양도세, 증여세, 상속세, 종합소득세, 퇴직금, 실업급여, 주택담보대출, 전세자금대출, 적금·예금, 전기세 등 한국 제도 기준 계산기.
• Home and outdoors (9) — air filter sizes, HVAC filter schedules, wood stain coverage, boat trailer sizing and tongue weight, humidity, fire extinguishers, water purification.
• Lottery (9) — number generators with official past-draw records for Korea, Thailand, the US (Powerball, Mega Millions), the UK, EuroMillions, Eurojackpot, Brazil and Japan.
• Legal templates (7) — NDA, cease and desist, contract termination, power of attorney, privacy policy, terms of service, trademark search guidance.
• US finance and tax (6) — federal and state estate tax, income tax, retirement, home equity, car lease, overtime pay.
• Health and skin (5) — BMI, running calories, altitude sickness, retinol, skincare routines, pet medication dosage.
• Other (5) — watts/amps/volts, batting average, engagement rate, belt sizes, audio file formats.

How We Keep These Right

A calculator is only worth using if its numbers are current, so we check them against the bodies that publish them and record the date we looked.

• We cite the primary source, not a summary. Tax thresholds come from the IRS and the individual state revenue departments, Korean figures from 국세청 and 법제처 statute text, electricity rates from 한국전력, water treatment guidance from the CDC, trademark procedure from the USPTO, and every lottery record from that game's official operator.
• When a figure cannot be verified, we say so on the page rather than guessing. The estate tax page, for example, notes that the District of Columbia figure is its published 2025 amount because DC has not yet published one for 2026.
• Rules that changed get re-checked, not assumed. Washington's estate tax exclusion, Maine's and New York's annual indexing, and Connecticut's link to the federal exemption are all read from the state's own tables each time.
• Estimates are labelled as estimates. These tools are for orientation. They are not tax, legal, medical or financial advice, and complicated situations need a professional.

Our Technology

Every tool runs entirely in your web browser using standard HTML, CSS, and JavaScript. No data is sent to external servers, ensuring your privacy and fast performance. Our site is hosted on Cloudflare's global CDN for the fastest possible loading times worldwide.

Contact

Have a suggestion for a new tool? Found a bug? We'd love to hear from you at sungje5575@gmail.com or visit our contact page.