📖 Complete User Guide

Learn every feature of the True Cost Calculator – step by step

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1
Getting Started
📘 What is the True Cost Calculator? It reveals the REAL cost of groceries after accounting for waste, shrinkage, and spoilage – showing which package gives the best value.
  • Click "➕ New Comparison" or use a template button to start.
  • Enter Price and Amount for each option.
  • The calculator automatically highlights the ⭐ BEST value.
  • Click "🛒 Basket" to add the winner to your shopping basket.
💡 Tip: You can rename a comparison by clicking the name field at the top of each group.
2
Setting Waste Percentage
📘 What is Waste Percentage? The portion of product you cannot use – liquid in cans, bones in meat, peels, etc. The calculator deducts this to show true edible cost.
  • Use preset buttons (Canned, Bone‑in, etc.) or drag the slider (0‑85%).
  • Higher waste = higher true cost per ounce.
  • Common waste values: 35% for canned in liquid, 40% for bone‑in meat, 25% for fresh produce, 0% for rice/oil/milk.
💡 Example: A $1.25 tuna can with 35% waste has true cost $0.38/oz; a $1.00 pouch with 5% waste costs $0.40/oz – the pouch is actually better value because you get more tuna per dollar.
3
Shelf Life & Bulk Trap Prevention
📘 Why use the Usage slider? Prevents the "bulk trap" – a large package may look cheaper per unit, but if you can't use it all before expiry, the true cost skyrockets.
  • Each item has a "Usage" slider (0‑100%). Set the percentage you expect to actually consume.
  • Example: 100% for milk you'll finish, 25% for a bulk jar of mayo that will spoil.
  • The true cost increases as usage decreases.
💡 Example: A 5lb rice bag at $0.30/lb seems cheap, but with 60% usage the true cost becomes $0.50/lb – more expensive than a smaller bag you'd finish.
4
Units & Currency Settings
📘 Auto-Convert Units – Automatically converts all amounts to the same unit (oz, kg, 100g, etc.) so you compare fairly.
  • Toggle the switch at the top of the calculator.
  • Example: 16oz vs 1kg becomes both expressed as price per 100g.
📘 Display Unit – Select how you want the TRUE COST to be shown (per ounce, per kg, per 100g, etc.).
  • Use the dropdown next to "Auto-Convert".
  • Click "Apply" to update all cards.
📘 Multi‑Currency – Choose a global currency (top dropdown) or set a different currency per card.
  • Global currency affects all cards that haven't been manually overridden.
  • Each price has its own currency selector – change it for that specific product.
  • The 💱 currency pill at the bottom of each comparison shows live exchange rates between different currencies used in that group.
📘 Refresh Exchange Rates – Updates live exchange rates from the Frankfurt API.
  • Click the purple button "🔄 Update Currency Exchange Rates" (appears both in the top bar and in each comparison footer).
  • Rates are updated automatically on page load, but you can refresh manually at any time.
💡 Pro tip: Use different currencies per card to compare prices across countries – the calculator will convert everything to a common base using live forex rates.
5
Quick Templates & Managing Comparisons
📘 Quick Templates – Pre‑built comparisons for common grocery categories.
  • Scroll through the template buttons (Meat, Seafood, Dairy, etc.) and click any template to instantly create a new comparison group.
  • You can then edit the price, amount, waste, and usage as needed.
📘 Adding / Removing Options
  • ➕ Option – Adds a new blank card to the current comparison group.
  • ✕ Delete (on each card) – Removes that option (requires at least one card remaining).
  • Delete comparison group – Click the red "Delete" button in the group header to remove the whole group (keep at least one group).
📘 Editing Product Name
  • Click the text field at the top of each card to rename the option (e.g., "Name Brand", "Store Brand").
  • The group name can be edited by clicking the text field in the group header.
💡 Tip: You can have as many options per comparison as you like – add more to compare 3, 4, or more products at once.
6
Shopping Basket Tracker
📘 Build your shopping list by adding winning items to the basket – tracks total trip cost in real time.
  • After the calculator highlights the ⭐ BEST option, click the "🛒 Basket" button (in the group header).
  • The item is added to the basket at the bottom of the page, and the total updates instantly.
  • Click "Clear All" to start a new shopping trip.
  • The basket saves automatically in your browser – your list persists even after refreshing.
💡 Use case: As you go through the store, add each best‑value item to your basket. The running total helps you stay under budget.
📷
Barcode Scanner
📘 Scan product barcodes to auto‑fill name, amount, and waste percentage – saves manual entry.
  • Inside any card, click the "📷 Scan Barcode" button.
  • Allow camera access when prompted.
  • Hold the barcode in front of the camera – the scanner will detect it automatically.
  • The product name, weight, and appropriate waste preset (e.g., 35% for canned goods) are filled for you.
  • You must still enter the price manually – the scanner only pulls product details from the database or Open Food Facts API.
💡 Pro tip: Works with most grocery barcodes. If a product is not recognised, you can enter the details manually.
💾
Export, Import & Reset
📘 Save your comparisons or restore a previous state.
  • 📤 Export – Saves all your current groups, items, settings, and basket as a JSON file. Great for backup or sharing.
  • 📥 Import – Load a previously exported file to restore all data.
  • 🗑️ Reset – Clears everything and restores the default two comparison groups (Tuna and Chicken).
💡 Note: Export/import preserves all waste, usage, currency, and unit settings – perfect for comparing scenarios or saving shopping lists.
📊
Example: Tuna Can vs Pouch
ProductPriceAmountWasteUsageTrue Cost
Premium Pouch ⭐$1.002.5 oz5%100%$0.40/oz
Standard Can$1.255 oz35%100%$0.38/oz
📘 Despite the pouch having a higher price per ounce, it wins because the can has 35% water waste – you get more actual tuna per dollar.
💡 Key takeaway: Always consider waste and shelf life, not just the shelf price!
✨
Complete Features List
💰
Multi‑Currency
30+ currencies, per‑card override
🔄
Auto‑Convert Units
Normalises oz/lb/kg/ml/L
💧
Waste Slider + Presets
0‑85%, canned/bone‑in/fresh
📅
Usage/Shelf Life
Prevents bulk traps
🛒
Shopping Basket
Auto‑total, persists
🏆
Auto Best Value
Highlights winner + savings %
📤
Export/Import
Backup & restore comparisons
📷
Barcode Scanner
Auto‑fills product details
💱
Live Exchange Rate Pill
Shows rates between currencies
📋
Quick Templates
100+ grocery presets
➕
Add/Delete Options
Flexible group editing
🗑️
Reset All
Restore default comparisons
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Smart Grocery Master v9.0 | Stop Paying for Packaging Waste