Discover why ending inventory value is not obvious just from counting what remains on the shelf
Why Counting Units Isn't Enough
Sarah can count what's on the shelf. She can count what she bought. She can count what she sold. But when she tries to put a dollar value on what remains, she runs into a problem.
Remember Sarah's Client Launch Kits from Lesson 1? She's been buying them in batches throughout the month. Here's what happened:
Beginning Inventory
10 kits
$18 each = $180 total
Purchases
20 kits
$20 each = $400 total
Sold
15 kits
Selling price: $38 each
Quick math check:
10 + 20 - 15 = 15 kits remaining on the shelf.
But here's the puzzle: What are those 15 kits worth in dollars?
Sarah knows she has 15 kits left. But when she asks her bookkeeper for the dollar value, she gets a surprising answer:
"Well, that depends. The 15 kits remaining could be worth $255 or they could be worth $285. I need to know which cost assignment method you want to use."
Two different answers. Both could be correct. Sarah stares at her spreadsheet, confused. How can the same 15 kits have two different values?
The kits were bought at different prices: some at $18, some at $20. When Sarah sold 15 kits, which ones did she sell? The cheaper ones? The more expensive ones? A mix? That choice determines what's left.
In Lesson 1, you learned the formula that drives this entire unit. Here it is again:
Today's lesson focuses on one question: How does inventory move through this formula?You'll learn that the formula works perfectly for counting units, but when dollars are involved, you need a rule for which costs go where.
Discussion prompt (3 minutes):
- If Sarah sold 15 kits, why can't we just say the remaining 15 kits are worth $285 (the average cost)?
- Why might an investor care whether Sarah reports $255 or $285 as her ending inventory?
- What would happen if Sarah just guessed and picked a number without understanding the rules?
1. Sarah started the month with 10 launch kits worth $180 total. She bought 20 more kits for $400. After selling 15 kits, she has 15 kits left on the shelf. Why can't she immediately tell you the dollar value of those 15 remaining kits?
2. Sarah's bookkeeper tells her the 15 remaining kits are worth either $255 or $285 depending on how costs are assigned. What does this mean for Sarah's business?
3. Why does the ending inventory number matter to someone outside the business, like a lender or investor?
4. In Lesson 1, you learned the formula: Ending Inventory = Beginning Inventory + Purchases - COGS. Which part of this formula is Sarah unsure about in this lesson?
Lesson 2 is about how inventory moves through the accounting system. You'll learn to track the flow of units and the flow of costs separately.
Key Concepts:
- • Physical flow vs. cost flow
- • Goods Available for Sale
- • Inventory layers
- • Where mistakes happen
Learning Objectives:
- • Trace inventory through the formula
- • Separate unit tracking from value tracking
- • Explain why cost assignment matters