Documentation & User Manual

ExpenseTrackerFree User Guide

A complete, transparent guide to using every feature on ExpenseTrackerFree.com, complete with exact mathematical formulas, practical examples, and tips for college students and everyday planners.

⚡ Quick Navigation Index

1. Core Philosophy & Privacy 2. Free Expense Tracker 3. Monthly Budget Calculator 4. Daily Budget Calculator 5. Runway Calculator 6. Student Budget Calculator 7. Savings Target Calculator 8. Expense & Bill Splitter 9. Backup, Export & Shortcuts

Section 1

Core Architecture & Privacy

ExpenseTrackerFree.com is engineered as a client-side, privacy-first personal finance platform. Unlike traditional banking apps, your data never leaves your personal browser.

🔒 100% On-Device Storage

All transactions, custom budget thresholds, and user preferences are serialized into standard browser localStorage under the key etf_v1_data. No cloud database or third-party server ever receives your numbers.

⚡ Multi-Island Reactive Sync

Whenever you log an expense, switch currencies, or update your budget in any tool or tab, an immediate custom browser event (etf_storage_update) updates all other open widgets simultaneously without a page refresh.

🎓 Student Mode vs. General Mode

Toggle between Student Mode (PG/hostel rent, mess & canteen meals, chai/snacks, photocopy, semester fees) and General Mode (groceries, utilities, EMI, health insurance, fuel) at any time from the top bar or settings.

🌍 9 International Currencies

Native formatting support for INR (₹), USD ($), EUR (€), GBP (£), CAD (CA$), AUD (AU$), JPY (¥), SGD (SGD$), and AED (AED) with international number localization.

Section 2

Free Expense Tracker (Main Dashboard)

The main tracker (Home Page) allows you to log daily purchases, categorize spending, specify payment channels (UPI, Cash, Cards), and monitor monthly limits.

How to Use:

Set Monthly Budget: Enter your total monthly allowance or salary budget in the top overview card.
Add Expense: Enter the amount, pick a category (e.g., Mess Food, Chai & Snacks), select payment method (UPI, Cash, Debit, etc.), add an optional note, and click Add Expense.
Real-time Metrics: The dashboard instantly computes your Total Monthly Spend, Remaining Balance, and Safe Daily Spend.

Exact Mathematical Formulas:

1. Total Spent = Sum of all expense amounts in the current calendar month

2. Remaining Budget = Monthly Budget - Total Spent

3. Safe Daily Spend = (Remaining Budget - Reserved Emergency Fund) ÷ Days Remaining in Month

4. Budget Utilization % = min(100, (Total Spent ÷ Monthly Budget) × 100)

Note: Days Remaining in Month includes today. If Remaining Budget is negative, Safe Daily Spend shows 0 with an over-budget notice.

Section 3

Monthly Budget Calculator

Located at /budget-calculator, this tool breaks down your income into fixed obligations, savings goals, and flexible discretionary allowance.

Inputs & Configuration:

Monthly Income / Allowance ($I$): Total earnings or parent allowance received each month.
Fixed Expenses ($F$): Unavoidable monthly costs (PG rent, tuition, bills, subscriptions).
Target Savings Goal ($S$): Amount you want to set aside in savings or emergency reserve.
Days in Month ($D$): Default 30 days (customizable).

Exact Mathematical Formulas:

1. Spendable Monthly = max(0, Monthly Income - Fixed Expenses - Savings Goal)

2. Daily Spendable Budget = Spendable Monthly ÷ Days in Month

3. Weekly Spendable Budget = Daily Spendable Budget × 7

4. Fixed Ratio % = (Fixed Expenses ÷ Monthly Income) × 100

5. Savings Ratio % = (Savings Goal ÷ Monthly Income) × 100

6. Spendable Ratio % = 100 - Fixed Ratio % - Savings Ratio %

Automated Status Logic:

• Healthy: Spendable Monthly allowance is ≥ 15% of total income.

• Tight: Spendable Monthly allowance is < 15% of total income.

• Deficit: Fixed Expenses > Income OR Savings Goal > (Income - Fixed Expenses).

Section 4

Daily Budget Calculator

Located at /daily-budget-calculator, this tool answers: "How much can I safely spend per day for the rest of this month without going broke?"

Exact Mathematical Formulas:

1. Available Spending Pool = max(0, Money Remaining - Reserved Amount)

2. Safe Daily Budget = Available Spending Pool ÷ Days Remaining

3. Weekly Spending Limit = Safe Daily Budget × min(7, Days Remaining)

Example Scenario:

You have ₹4,500 left in your bank account with 10 days remaining in the month, and you want to keep ₹1,000 as emergency savings:

Available Spending = ₹4,500 - ₹1,000 = ₹3,500
Safe Daily Budget = ₹3,500 ÷ 10 days = ₹350 / day

Section 5

Money-Last Runway Calculator (Burn Rate)

Located at /money-last-calculator, this tool projects how many days, weeks, and months your current funds will last based on your average daily burn rate.

Exact Mathematical Formulas:

1. Spendable Capital = max(0, Available Balance - Upcoming Fixed Expense)

2. Exact Runway Days = Spendable Capital ÷ Daily Spend

3. Displayed Days = floor(Exact Runway Days)

4. Displayed Weeks = round((Exact Runway Days ÷ 7) × 10) ÷ 10

5. Displayed Months = round((Exact Runway Days ÷ 30) × 10) ÷ 10

Interactive "What-If" Sensitivity Table:

The runway calculator automatically simulates 5 spending scenarios so you can visualize the impact of lifestyle adjustments:

Scenario	Burn Multiplier	Formula
25% Less Spending (Frugal)	0.75 × Daily Spend	floor(Spendable ÷ (Daily Spend × 0.75))
Current Spending (Baseline)	1.00 × Daily Spend	floor(Spendable ÷ Daily Spend)
25% More Spending (Relaxed)	1.25 × Daily Spend	floor(Spendable ÷ (Daily Spend × 1.25))
50% More Spending (Heavy)	1.50 × Daily Spend	floor(Spendable ÷ (Daily Spend × 1.50))
2x Spending (Splurge)	2.00 × Daily Spend	floor(Spendable ÷ (Daily Spend × 2.00))

Section 6

Student Budget Calculator (PG / Hostel)

Located at /student-budget-calculator, this tool is tailored specifically for Indian and international college students living away from home.

5 Built-in Living Arrangement Presets:

1. Paying Guest (PG)

Preset with PG rent, mess food, commute, recharge, laundry & tea.

2. College Hostel

Hostel fees, canteen meals, books, photocopy, campus activities.

3. Day Scholar (Parents)

Bus/metro pass, canteen snacks, exam fees, tuition courses.

4. University Dorm

Dorm rent, campus meal plans, transit pass, supplies, social events.

5. Shared Flat / Roommates

Shared rent, groceries + cook share, Wi-Fi, electricity & leisure.

Exact Mathematical Formulas:

1. Total Monthly Cost = Sum of all itemized expense categories

2. Daily Average Student Cost = Total Monthly Cost ÷ 30

3. Category Share % = (Category Cost ÷ Total Monthly Cost) × 100

4. Discretionary Food Alert = Triggered if (Chai + Snacks + Food Delivery + Outings) > 25% of Total

Section 7

Savings Target Calculator

Located at /savings-calculator, this tool breaks down a financial goal (e.g., buying a laptop, emergency fund, vacation) into daily, weekly, and monthly milestones.

Exact Mathematical Formulas:

1. Remaining Savings Gap = max(0, Target Goal - Current Savings)

2. Savings Progress % = min(100, (Current Savings ÷ Target Goal) × 100)

3. Required Monthly Savings = Remaining Gap ÷ Timeline (Months)

4. Required Weekly Savings = Remaining Gap ÷ (Timeline in Months × 4.333)

5. Required Daily Savings = Remaining Gap ÷ (Timeline in Months × 30.416)

Example:

Goal = ₹60,000 for Laptop | Saved = ₹10,000 | Timeline = 5 Months
Remaining Gap = ₹50,000
Required Monthly = ₹50,000 ÷ 5 = ₹10,000 / month
Required Weekly = ₹50,000 ÷ 21.66 = ₹2,308 / week
Required Daily = ₹50,000 ÷ 152.08 = ₹329 / day

Section 8

Expense & Bill Splitter

Located at /expense-splitter, this tool provides both Simple Restaurant Splitting (with tip/service charge) and Itemized Group Bill Settlement with minimum transfer debt resolution.

1. Simple Split Formulas (Dining & Parties):

Tip Amount = Total Bill × (Tip % ÷ 100)

Grand Total = Total Bill + Tip Amount

Share Per Person = Grand Total ÷ Number of People

2. Itemized Debt Settlement Algorithm (Greedy Solver):

When multiple roommates or trip members pay different amounts for groceries, hotel, cabs, or dinner, the algorithm minimizes the total number of peer-to-peer bank transfers:

1. Total Group Spent = Sum(Paid by all participants)

2. Equal Fair Share = Total Group Spent ÷ Count of participants

3. Net Balance for each person = Amount Paid - Equal Fair Share

• If Net Balance > 0: Creditor (they are owed money)

• If Net Balance < 0: Debtor (they owe money)

4. Match largest debtor with largest creditor iteratively:

Transfer Amount = min(|Debtor Debt|, Creditor Credit)

Deduce transfer until all balances reach zero.

Section 9

Data Backup, Export & Keyboard Shortcuts

Export & Import Workflows:

💾 JSON Full Backup

Downloads a complete offline backup file (etf-backup-YYYY-MM-DD.json) containing all expenses, categories, and settings.

📊 CSV Spreadsheet Export

Exports your transactions formatted for direct import into Microsoft Excel, Google Sheets, or Apple Numbers.

📥 JSON Backup Restore

Restores your complete financial history on a new laptop, mobile browser, or after clearing browser history.

Universal Keyboard Shortcuts:

Shortcut	Action	Scope
Ctrl + K / ⌘ + K	Open Universal Feature & Calculator Search Spotlight	Global (Any page)
/ (Forward Slash)	Focus Universal Search (when not typing in form inputs)	Global (Any page)
Escape (ESC)	Close modal search, export popup, or confirmation dialog	Global (Any modal)
↑ / ↓ (Arrow Keys)	Navigate search recommendations and quick tools	Universal Search Modal
Enter (↵)	Execute selected tool navigation or action	Universal Search Modal

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