Accumulated Depreciation
The contra-asset account—tracking how much value has been "used up".
Why This Matters
Your company bought a machine 3 years ago for $100,000. The balance sheet shows:
Question: Is that machine really worth $100,000 today?
Of course not. It's been used for 3 years. It's worn. It's older. It's lost value. But we don't change the Equipment account. The machine still cost $100,000—that's historical fact.
Instead, we track how much value has been "used up" in a separate account: Accumulated Depreciation.
Equipment:$100,000
Less: Accumulated Depreciation(30,000)
Book Value:$70,000
Now the story is complete:
The machine cost $100,000, we've expensed $30,000 of that over 3 years, and the remaining book value is $70,000. Accumulated Depreciation is the bridge between what you paid and what's "left" on your books. Without it, you'd either lie about asset values or lose the historical cost information.
What Is Accumulated Depreciation?
Accumulated Depreciation is the total amount of depreciation expense recorded against an asset since it was acquired.
Asset Account
Equipment
$100,000
(What you paid)
Contra-Asset Account
Accum. Depr.
-$30,000
(What you've expensed)
= Book Value: $70,000
(What's "left" on the books)
It's called "accumulated" because it ADDS UP over time:
Year 1: $10,000 depreciation Accum Depr = $10,000
Year 2: $10,000 depreciation Accum Depr = $20,000
Year 3: $10,000 depreciation Accum Depr = $30,000
Each year's expense gets ADDED to the running total.
The Contra-Asset Concept
Accumulated Depreciation is a contra-asset account. That's a fancy term for an account that:
- Is linked to an asset account
- Has the opposite normal balance (credit instead of debit)
- Reduces the reported value of the related asset
Normal Asset
Debit Balance (increases w/ Debits)
Contra-Asset
Credit Balance (increases w/ Credits)
Equipment
Debit
100,000
.
.
Bal: 100,000
Credit
.
.
.
Accum. Depreciation
Debit
.
.
.
Credit
10,000 Yr 1
10,000 Yr 2
10,000 Yr 3
Bal: 30,000
How Accumulated Depreciation Grows
Each period, when you record depreciation expense:
Depreciation Expense10,000
Accumulated Depreciation10,000
Building Over Time (5-Year Life, $0 Salvage)
| Year | Annual Depr. Exp. | Accumulated Depr. | Book Value |
|---|---|---|---|
| 0 (Purchase) | — | $0 | $100,000 |
| 1 | $10,000 | $10,000 | $90,000 |
| 2 | $10,000 | $20,000 | $80,000 |
| 3 | $10,000 | $30,000 | $70,000 |
| 4 | $10,000 | $40,000 | $60,000 |
| 5 | $10,000 | $50,000 | $50,000 |
Notice:
- Accumulated Depreciation only goes UP (it accumulates)
- Book Value only goes DOWN (as more gets "used up")
- At end of useful life, Book Value = Salvage Value (if any)
Visual: Asset Value Over Time
Accumulated vs. Depreciation Expense
Students often confuse these two completely different accounts.
Depreciation Expense
Income Statement
- • Current period only
- • Resets each year (closed out)
- • Reduces net income
- • Debit balance
- • Temporary account
Year 3 expense: $10,000
Accum. Depreciation
Balance Sheet
- • Cumulative total
- • Grows over time
- • Reduces asset book value
- • Credit balance (Contra-Asset)
- • Permanent account
After 3 years: $30,000
Think of it like a water faucet and a bucket:
Depreciation Expense = water flowing this period (the faucet).
Accumulated Depreciation = total water collected (the bucket).
Balance Sheet Presentation
Accumulated Depreciation appears on the balance sheet in three common formats:
Format 1: Detailed (Most Informative)
Property, Plant & Equipment:
Land$200,000
Buildings$500,000
Less: Accumulated Depreciation(100,000)
400,000
Equipment$300,000
Less: Accumulated Depreciation(120,000)
180,000
Format 2: Condensed
Property, Plant & Equipment:
Land$200,000
Buildings, net400,000
Equipment, net180,000
Format 3: Single Line
PP&E, net$828,000
Note: PP&E is stated at cost of $1,080,000 less accumulated depreciation of $252,000.
Fully Depreciated Assets
What happens when accumulated depreciation equals the depreciable base?
The Math
Cost:$100,000
Salvage Value:$10,000
Depreciable Base:$90,000
After Full Depr.
Accum. Depr:$90,000
Book Value:$10,000
The asset stays on the books at cost minus accumulated depreciation (book value = salvage) as long as it's still in use.
No more depreciation is recorded once book value reaches salvage value. The journal entries stop.
The asset is only removed when it's disposed of (sold, scrapped, or traded).
Common Mistakes
Confusing the Accounts
❌ "Our accumulated depreciation expense this year was $10k"
✅ "Our depreciation expense this year was $10k, bringing accumulated depreciation to $30k"
Wrong Journal Entry
❌ Debiting Accumulated Depreciation (that decreases it!)
✅ Debit Depreciation Expense, Credit Accumulated Depreciation.
Depreciating Past Salvage
❌ Continuing to depreciate after book value hits salvage value.
✅ Stop depreciation when Book Value = Salvage Value.
Depreciating Land
❌ Recording Accumulated Depreciation—Land.
✅ Land is NEVER depreciated. No accumulated depreciation account exists for land.
Key Takeaway
Accumulated Depreciation is the contra-asset account that tracks total depreciation recorded against an asset since acquisition. It increases (credits) each period when depreciation expense is recorded.
Book value equals cost minus accumulated depreciation. Unlike depreciation expense (which resets each year on the income statement), accumulated depreciation is permanent and grows over time on the balance sheet. Assets stay on the books at salvage value when fully depreciated, and accumulated depreciation is only removed when the asset is disposed of.
Test Your Understanding
See if you've got the basics down. Click each option and check your answer.
Question 1: Accumulated Depreciation is classified as a:
Question 2: Equipment costs $50,000 with $5,000 salvage and a 5-year life. After 3 years of straight-line depreciation, what is the accumulated depreciation?
Question 3: The journal entry to record annual depreciation includes:
Question 4: An asset is fully depreciated but still in use. What appears on the balance sheet?
Question 5: Accumulated Depreciation is:
Ready to Practice?
You now understand how accumulated depreciation works. The Practice Lab challenges you to build depreciation schedules, track running totals, and format balance sheets.
Try the Practice LabWhat's Next?
You've learned how to record and track PPE over its life. Now what happens at the end? Disposal of Assets covers selling, discarding, or trading fixed assets.