Overview

EMI Loan Calculator & Finance Tools is a complete Flutter app for Android and iOS. It packs 17 loan, investment and tax calculators and 12 everyday tools into one clean app, with month-by-month amortization schedules, donut charts, calculation history and an AI finance assistant powered by Groq (Llama 3.3 70B). It is built with GetX, ships light and dark themes and 12 UI languages, and earns from both AdMob ads and in-app purchases. This is the same code base as a live Google Play app, cleaned and documented so you can rebrand and publish it fast.

Key features

Loan & EMI calculators

• EMI calculator with 6 loan presets (Personal, Car, Student, Cash, Bank, Credit). It shows the EMI, total interest, total payment, payoff date and a breakdown bar.
• Full amortization schedule: month-by-month payment, interest, principal and balance, grouped by year
• House loan calculator: down payment (% or amount), property tax, PMI, insurance and HOA, with a donut chart
• Business loan calculator with monthly, quarterly, half-yearly or yearly payments
• Loan compare: compare two loans side by side and add more

Investment, banking & tax calculators

• FD, RD, SIP and PPF, with maturity value, gains and charts
• Simple interest (years, months or days) and compound interest (any compounding frequency)
• GST and VAT calculators that add or remove tax

12 everyday tools

• Currency converter with live rates and an offline fallback
• Discount, inflation, percentage, percentage difference and percentage change
• Amount in words (lakh/crore and million formats)
• Length, speed, temperature and mass converters, and an age calculator

AI Finance Assistant

• Chat powered by Groq (llama-3.3-70b-versatile), with Markdown replies and suggested questions
• Chat history: open, delete and clear
• The API key comes from Firebase Remote Config. The assistant can be sold as a premium feature.

Experience & engagement

• Bottom navigation: Dashboard, Tools, History and Settings
• Light and dark themes, 12 UI languages (English, Hindi, Gujarati, Marathi, Tamil, Telugu, Bengali, Spanish, French, German, Arabic, Portuguese) and 9 app currencies
• Automatic calculation history, stored on the device
• Exit-intent carousel, rate-us dialog with feedback, in-app review and in-app update check
• Push notifications (FCM + local) with deep links, and a no-internet dialog
• Firebase Analytics, Crashlytics and Facebook App Events

What's included

• Full Flutter source code: GetX controllers and views for every calculator and tool, the ad engine and the IAP module
• Android project (Kotlin) with 4 custom native-ad layouts and factories
• iOS project (deployment target 15.0) with the AdMob test App ID and Facebook placeholders preconfigured
• README with a step-by-step setup guide: rebranding, Firebase, ads, IAP products, Groq, signing, iOS and troubleshooting
• Ad configuration template (ads_service JSON with Google test IDs, auto-loaded in debug builds) and an IAP plans template
• key.properties signing template, LICENSE and CHANGELOG
• All secrets replaced with placeholders. The project builds out of the box with a debug-key fallback.

Tech stack

• Flutter 3.38.4+ (tested on Flutter 3.47.4 / Dart 3.13), GetX, GetStorage, Nunito font
• Firebase: Core, Remote Config, Cloud Messaging, Analytics and Crashlytics
• Monetization packages: google_mobile_ads 8.x and in_app_purchase 3.x (Google Play Billing / StoreKit)
• AI: groq_sdk and flutter_markdown_plus
• Other packages: currency_picker, live_currency_rate, responsive_framework, carousel_slider
• Android: AGP 8.11, Kotlin 2.2, Gradle 8.14, Java 17, minSdk 24, target/compile SDK 36, R8 minify and shrink enabled

Requirements

• Flutter SDK 3.38.4 or newer, Android Studio or VS Code, and JDK 17
• Xcode 16+ and CocoaPods for iOS builds
• Your own Firebase project, AdMob account, and Play Console / App Store Connect account for in-app products
• A Groq API key for the AI chat (optional; a free tier is available)

Setup in minutes

• Run flutter pub get, then flutterfire configure
• Change the package id and app name, then generate your icon with flutter_launcher_icons
• Add your AdMob App ID and publish the Remote Config parameters: ads_service, iap_plans, isPremium and Ai_boat_config
• Create the products remove_ads and ai_chat_unlock in Play Console and App Store Connect
• Add your keystore and run flutter build appbundle

Monetization (ads/IAP)

• AdMob: App Open (splash and resume), banner, native small and large, and interstitial with a frequency cap
• Remote ad control: one Firebase Remote Config JSON sets the master switch, every ad unit ID, frequency and positions, with primary and secondary ID fallback
• In-app purchases: a paywall with plans from Remote Config, restore purchases, and two non-consumable products. Premium users get no ads and an unlocked AI chat.
• Ad revenue (paid events) is logged to Firebase Analytics

Support & updates

Support is provided through the Aadhya Infotech DevStore: https://www.aadhya-infotech.com/DevStore/contact. Bug-fix updates for this package are published on the DevStore.