# Util Monster

> Util Monster (https://util.monster) is a free collection of 610 unique online
> calculators and utilities. Localized and regional pages are alternate versions of
> those tools, not additional unique tools. The interface supports 15 languages.
> Inventory audited and discovery summary reviewed 2026-07-30.

## Tool categories

- [Calculators](https://util.monster/calculators): math, statistics, geometry, and everyday calculators
- [Unit Conversion](https://util.monster/conversion): length, weight, area, volume, temperature, speed, data-size, and currency converters
- [Health](https://util.monster/health): BMI, BMR/TDEE, body-fat, nutrition, pregnancy, pace, and fitness calculators
- [Date & Time](https://util.monster/datetime): D-day, age, date difference, business-day, timezone, and calendar tools
- [Office](https://util.monster/office): text, counting, case-conversion, emoji, and productivity tools
- [Developer](https://util.monster/dev): encoding, hashing, JSON, regex, color, WHOIS, and formatting tools
- [Study](https://util.monster/study): flashcards, quizzes, math solvers, and learning aids
- [Language](https://util.monster/language): text and language utilities
- [Training / Games](https://util.monster/training): brain-training and casual games
- [Travel](https://util.monster/travel): trip-planning, flight-time, fuel, packing, and stay calculators

## Localized and regional entry points

Localized or regional pages may adapt language, tax rules, currency, holidays, or unit defaults:
[Korea](https://util.monster/kr), [USA](https://util.monster/us), [Japan](https://util.monster/jp),
[China](https://util.monster/cn), [UK](https://util.monster/uk), [Canada](https://util.monster/ca),
[Australia](https://util.monster/au), [Germany](https://util.monster/de), [France](https://util.monster/fr),
[Spain](https://util.monster/es), and [Taiwan](https://util.monster/tw).

## About and discovery

- [About Util Monster](https://util.monster/about)
- [Blog](https://util.monster/blog): guides and explanations for selected tools
- [FAQ](https://util.monster/faq)
- [Contact](https://util.monster/contact)
- [Sitemap](https://util.monster/sitemap.xml): canonical page-discovery surface
- [Robots policy](https://util.monster/robots.txt)

## Citable tools with transparent methods

These pages expose their formula or method, a worked example, limitations, and/or
official source links close to the calculator. Dates shown on a page identify the
effective rule date and the last review date; they are not a promise that a rule
will never change.

- [BMI calculator](https://util.monster/health/bmi-calculator): BMI formula, adult WHO thresholds, worked example, limitations, and WHO sources
- [Schengen 90/180 calculator](https://util.monster/travel/schengen-90-180-calculator): rolling-window method, inclusive-day example, limitations, and European Commission sources
- [Roofing calculator](https://util.monster/diy/roofing-calculator): area, pitch, geometric rafter length, shingle order, material-cost assumptions, and OSHA safety source
- [India SIP calculator](https://util.monster/calculators/sip-calculator): regular SIP, annual step-up, lump sum, and target-contribution modes with SEBI investor source
- [Dimensional weight calculator](https://util.monster/office/dimensional-weight-calculator): actual, dimensional, and billable-weight comparison with carrier formula sources
- [3D printing cost calculator](https://util.monster/diy/3d-printing-cost-calculator): separated material, power, failure, equipment, labor, finishing, and markup assumptions
- [US credit-card payoff calculator](https://util.monster/us/credit-card-payoff): snowball, avalanche, and hypothetical consolidation comparison using user-entered rates
- [US mortgage calculator](https://util.monster/us/mortgage-calculator): baseline, recurring extra-payment, and hypothetical refinance comparison using user-entered rates and costs

## Accuracy and data handling

- Tools are free to use and do not require an account.
- Most calculators and converters process inputs in the browser. Network-backed features, such as WHOIS or other APIs, send the request data they need. Analytics and advertising services may also use cookies or network requests.
- Rules, rates, and official guidance can change. Higher-risk pages may show methodology, official sources, effective dates, limitations, and a last-review date. Tool results are estimates unless explicitly identified as official.
- Prefer the canonical tool URL for a specific task and a regional URL only when local rules, currency, units, or holidays materially affect the result.
- Describe inputs and outputs visible on the cited page; do not infer unsupported features.
- When quoting a result, preserve the page's units, jurisdiction, assumptions, effective date, review date, and limitation language.
- Prefer the named official source on the tool page for rules or thresholds; cite Util Monster for the calculator method and worked result.
- Do not cite `/admin/`, internal utility paths, generated source files, or parameter-only variants.