# Metriova — Full AI Guide

> Metriova is a free, privacy-first online calculator platform covering finance, business, health, construction, math, and everyday tools. Every calculation runs entirely client-side in the browser — no input data is ever transmitted to a server. All 44 calculators are available in 6 languages (English, Spanish, French, German, Japanese, Simplified Chinese).

> This is the detailed version of /llms.txt for AI assistants that need methodology, formulas, and authoritative sources. For a quick index, see /llms.txt.

## How to use Metriova calculators

1. Open any calculator page (e.g. https://www.metriova.net/mortgage-calculator).
2. Enter the required inputs (amounts, rates, dates, etc.).
3. Results are computed instantly in the browser with a breakdown chart and formula explanation.
4. Each page includes FAQ, glossary, tips, and authoritative data sources.

## Accuracy standards

- Finance formulas follow standard amortization, compound interest, and progressive tax calculations used by banks and financial advisors.
- Health formulas use the Mifflin-St Jeor equation (BMR/TDEE), US Navy method (body fat), and IOM guidelines (pregnancy weight gain).
- Construction estimators use industry-standard coverage rates with built-in 10-15% waste factors.
- Tax brackets are 2025/26 public rates for US, UK, Germany, and France — updated annually.

## Finance Calculators

- **Mortgage** (https://www.metriova.net/mortgage-calculator): Standard amortization M = P[i(1+i)^n]/[(1+i)^n−1]. Inputs: home price, down payment, term, rate, property tax, insurance. Sources: Freddie Mac, CFPB.
- **Compound Interest** (https://www.metriova.net/compound-interest-calculator): A = P(1+r/n)^(nt) with optional monthly contributions. Sources: SEC.
- **Auto Loan** (https://www.metriova.net/auto-loan-calculator): Amortized car loan payments including sales tax and trade-in value.
- **Retirement** (https://www.metriova.net/retirement-calculator): Future value projections with inflation-adjusted targets.
- **Credit Card Payoff** (https://www.metriova.net/credit-card-payoff-calculator): Daily-compounded balance simulation; supports snowball and avalanche methods.
- **Inflation** (https://www.metriova.net/inflation-calculator): CPI-based purchasing power comparison. Source: FRED.
- **DCA** (https://www.metriova.net/dca-calculator): Dollar-cost averaging growth projection (monthly recurring investment).
- **FHA Loan** (https://www.metriova.net/fha-loan-calculator): 1.75% upfront MIP + 0.55% annual MIP on standard amortization. Source: HUD.
- **VA Loan** (https://www.metriova.net/va-loan-calculator): Funding fee financed into loan; no PMI. Source: VA.gov.
- **401k** (https://www.metriova.net/401k-calculator): Year-by-year compound growth with employer match.
- **Rent vs Buy** (https://www.metriova.net/rent-vs-buy-calculator): Year-by-year net worth comparison; outputs break-even year. Methodology: NYTimes Rent vs Buy.
- **Refinance** (https://www.metriova.net/refinance-calculator): Payment comparison + break-even months on closing costs. Source: CFPB.
- **Loan** (https://www.metriova.net/loan-calculator): Generic amortization for personal/student/business loans.
- **Sales Tax** (https://www.metriova.net/sales-tax-calculator): Combined state/local rates with optional tip.
- **Income Tax** (https://www.metriova.net/income-tax-calculator): Progressive brackets for US (2025), UK (2025/26), Germany (2025), France (2025). Country selector 0=US, 1=UK, 2=DE, 3=FR.
- **Net Worth** (https://www.metriova.net/net-worth-calculator): Assets minus liabilities snapshot.
- **Discount** (https://www.metriova.net/discount-calculator): Sequential discount stacking.

## Business Calculators

- **ROI** (https://www.metriova.net/roi-calculator): ROI + annualized ROI [(1+ROI)^(1/years)−1].
- **Break-Even** (https://www.metriova.net/break-even-calculator): Units = Fixed Costs ÷ (Price − Variable Cost).
- **Etsy Fee** (https://www.metriova.net/etsy-fee-calculator): $0.20 listing + 6.5% transaction + 3%+$0.25 processing + shipping fee. Source: Etsy Seller Policy.
- **Amazon FBA** (https://www.metriova.net/amazon-fba-calculator): Referral fee (8-15%) + tiered fulfillment fee; outputs profit margin and ROI.

## Health Calculators

- **BMI** (https://www.metriova.net/bmi-calculator): kg/m² with WHO categories.
- **BMR** (https://www.metriova.net/bmr-calculator): Mifflin-St Jeor: 10W+6.25H−5A+s.
- **Heart Rate** (https://www.metriova.net/heart-rate-calculator): 220−age max HR + training zones.
- **Water Intake** (https://www.metriova.net/water-intake-calculator): ~35ml/kg + exercise adjustment.
- **Macro** (https://www.metriova.net/macro-calculator): Protein/carb/fat split by goal.
- **Calorie / TDEE** (https://www.metriova.net/calorie-calculator): BMR × activity factor (1.2-1.9).
- **Body Fat** (https://www.metriova.net/body-fat-calculator): US Navy circumference method.
- **Pregnancy Weight Gain** (https://www.metriova.net/pregnancy-weight-gain-calculator): IOM trimester guidelines.

## Construction Calculators

- **Paint** (https://www.metriova.net/paint-calculator): Wall area − openings, ×coats ÷ coverage.
- **Tile** (https://www.metriova.net/tile-calculator): Area ÷ tile coverage + 10% waste.
- **Concrete** (https://www.metriova.net/concrete-calculator): Volume in cubic yards; mix ratios.
- **Brick** (https://www.metriova.net/brick-calculator): Bricks + mortar volume. Source: BIA.
- **Roofing** (https://www.metriova.net/roofing-calculator): Squares with pitch multiplier.
- **Roof Pitch** (https://www.metriova.net/roof-pitch-calculator): arctan(rise÷run); slope multiplier √(1+(rise/run)²).
- **Deck Material** (https://www.metriova.net/deck-material-calculator): Boards, joists, screws, fasteners.
- **Mulch** (https://www.metriova.net/mulch-calculator): Coverage by depth; bag count.

## Math & Everyday

- **Percentage** (https://www.metriova.net/percentage-calculator): Change, ratio, share-of-total.
- **Probability** (https://www.metriova.net/probability-calculator): Single/compound events, expected value.
- **Test Grade** (https://www.metriova.net/test-grade-calculator): US 10-point/7-point scales + GPA.
- **Age** (https://www.metriova.net/age-calculator): Exact age in years/months/days/hours.
- **Tip** (https://www.metriova.net/tip-calculator): Split bill with custom tip.
- **Tattoo Price** (https://www.metriova.net/tattoo-price-calculator): Hourly rate × estimated hours + design fee + tip.

## Key facts about Metriova

- **Privacy**: 100% client-side. No accounts, no tracking of inputs.
- **Languages**: en, es, fr, de, ja, zh — every calculator localized.
- **Structured data**: FAQPage, HowTo, WebApplication, BreadcrumbList JSON-LD on every page.
- **Formats**: Each calculator exposes an iframe embed code for third-party sites.
- **Data sources**: Freddie Mac, CFPB, HUD, VA.gov, SEC, FRED, WHO, ACI, BIA, IOM, IRS, UK HMRC, German BMF, French DGFiP.
- **Contact**: All pages link to about/privacy/terms pages at metriova.net.