About PiPi Worlds

The one-line version

"Calm tools and stories that respect three different markets — and never leave your browser." Korean readers have the 2023 unified-age law. Japanese readers have the 厚生労働省 dietary reference intakes. American readers have ACOG, the CDC, the FDA, the IRS. PiPi Worlds doesn't pretend these are interchangeable. We rewrite for each market, and we keep your inputs in your browser.

Why this exists

Search "pregnancy week calculator" in English and you'll find a thousand near-identical pages. Search the Japanese equivalent and you'll find translated versions of those same English pages, with the 母子健康手帳 timeline missing and Naegele's rule applied to Japanese cycle averages it wasn't built for. Search the Korean equivalent and you'll find Naver blog posts that confuse the unified-age law with Korean traditional age in the very next paragraph.

PiPi Worlds tries to do better. Same topic, different guides. Same tool, different cited sources. The English guide quotes ACOG Committee Opinion 700; the Japanese guide quotes 日本産科婦人科学会; the Korean guide quotes 대한산부인과학회. Trust starts with citing what actually applies to the reader sitting in front of the page.

Three operating principles

1. Privacy-first — the math runs in your browser

Your age, weight, pregnancy week, name, dog's behavior profile — none of it is sent to our server. All calculations happen in JavaScript that runs entirely in your browser. We don't proxy your inputs through analytics, an LLM endpoint, or a third-party API. If you share a result URL, the inputs travel in the query string to the recipient — but they still don't touch our servers. Ads are served by Google AdSense, and that behavior is documented in our Privacy Policy.

2. Re-creation, not translation

We publish each topic in three languages — Korean, Japanese, English — but we don't translate. The English version cites CDC, ACOG, FDA, IRS, the IRS specifically because those are the agencies the English-speaking reader can verify. The Japanese version cites 厚生労働省, JASSO, 日本産科婦人科学会. The Korean version cites KSSO, KDCA, 대한산부인과학회, 한국은행. Borrowing another market's government domain into a guide it doesn't apply to is a quality bug we actively guard against in our review pipeline.

3. Tested precision

BMI uses the WHO 2004 Asian cutoff or the standard cutoff depending on context, with the choice cited in the body. BMR uses Mifflin-St Jeor (1990); pregnancy due date uses Naegele's rule with the LMP/IVF/ultrasound base date you select. Compound interest distinguishes daily, monthly, and yearly compounding. Each formula has a unit test behind it, and the cited formula appears in the guide so a reader can verify the math themselves.

Operated by PiFl Labs

PiPi Worlds is operated by PiFl Labs, an independent studio that ships practical, calm tools across three markets. This is one of several sites the studio runs. Tools, articles, design decisions, and customer email are handled in-house by the PiFl Labs team — which keeps the editorial voice consistent and the response time short.

• Operator: PiFl Labs
• Support email: support@pifl-labs.com
• Studio: pifl-labs.com
• Business location: Republic of Korea

The ten tools

Every tool keeps the browser-only, no-server-transmission promise. Each tool's guide cites the primary sources that apply to its market.

• Age Calculator — exact years, days alive, days to next birthday, Western zodiac, Chinese zodiac. Localized for Korean unified-age law and Japanese school-year conventions when you switch markets.
• Interest & Loan Calculator — savings, recurring deposits, mortgages on one page. Simple, monthly, and yearly compounding; equal principal vs. equal payment amortization; tax-after-withholding adjustments; early-repayment fees.
• Character & Word Count — characters with and without spaces, bytes, words, lines, manuscript pages. Twitter, SEO meta, and admissions essay presets. Live highlighting when you go over the limit.
• Lunar ↔ Solar Calendar — bidirectional conversion across 1900–2099, sixty-cycle year/month/day, twenty-four solar terms, leap-month handling. For lunar birthdays, festivals, and ancestral memorial dates.
• QR Code Generator — URL, Wi-Fi, vCard, payment, plain-text payloads. High-resolution PNG and SVG export. Practical guides for merchants, weddings, travel, and small-business signage.
• BMI · BMR · TDEE Calculator — WHO standard or Asian cutoff (cited), Mifflin-St Jeor BMR, activity-multiplied TDEE. Long-form guides on plateau breaking, body composition, and sarcopenia in older adults.
• Pregnancy Week Calculator — choose LMP, IVF transfer, or ultrasound as your base. ACOG- and CDC-aligned guides for nutrition (folic acid 600 mcg, fish to avoid), weight gain (IOM 2009 by pre-pregnancy BMI), and the fourth-trimester recovery (ACOG Committee Opinion 736).
• Dog Breed Match — apartment compatibility, family situation, exercise demand. Built on AKC breed group data, ASPCA temperament notes, and Royal Canin nutritional baselines.
• US Paycheck Calculator — gross-to-net take-home pay for 2026. Social Security and Medicare (FICA), a federal income-tax estimate from the official IRS brackets, and an optional state-tax rate, with a full monthly deduction breakdown.
• Percentage Calculator — four modes: percent of a number, what percent X is of Y, percentage change between two values, and discounted price. Pure arithmetic, nothing leaves the browser.

How the writing gets made

Every article on this site goes through the same pipeline.

1. Per-market keyword research — Korean (Naver autocomplete, People Also Ask), Japanese (Yahoo!知恵袋, Google's "Other people also searched"), American (Google "People also ask"). We collect search intent for each market separately.
2. Primary-source verification — every number, law, and year in the body is checked against a primary source (.gov, .gov.uk, .go.kr, .go.jp, peer-reviewed journal, professional society guideline, Wikipedia). Claims that fail verification are removed rather than hedged.
3. Independent drafts — Korean, Japanese, and English drafts are written independently. We don't translate. Same topic, different examples, different tone, different citations.
4. Native-reader gate — each language draft is reviewed by a persona who reads in that market. Cultural mismatches, citations to the wrong country's government, named-doctor anecdotes — all of these cost points, and below threshold the draft gets rewritten.
5. Build-time SEO checks — canonical, hreflang, FAQ JSON-LD, internal-link trailing slashes, thumbnails, OG images — all checked at build time, not after publication.

AI tools help with first drafts, copy editing, and translation-quality checks. Fact verification and per-market tone calls are made by the PiFl Labs editorial team. We hold to that line because numbers, laws, and dates are the part of writing that absolutely cannot drift.

Ads & revenue

The site's operating costs are covered by Google AdSense. Ads only appear in positions that don't break body readability, and we don't ship pages where ads outweigh content. If a body link is sponsored or affiliate, it's labeled.

Full ad behavior is documented in our Privacy Policy and Terms of Service.

Feedback & corrections

Spotted a calculator bug, a typo, a factual mistake, or want to suggest a new tool? Email the address below. Replies usually go out within one to three business days.

• Email: support@pifl-labs.com
• Contact page
• Frequently asked questions