Dr. Paul Borosky, DBA, MBA
Business Consultant & Author
Guide 3 of 34 · Foundations
What Is the Accounting Equation?
One equation. Two somewheres.
Underneath every balance sheet, Apple’s included, sits one simple rule. Everything a company owns was paid for with borrowed money or owners’ money. Learn it on a ten-step coffee shop, and Apple’s $359 billion balance sheet stops looking mysterious.
Last Updated: 10/27/2026 · Written by Dr. Paul Borosky, DBA, MBA
The Short Answer
What Is the Accounting Equation?
Textbook Definition
The accounting equation states that a company’s assets equal the sum of its liabilities and shareholders’ equity. It is the foundation of double-entry bookkeeping and the balance sheet.
In Plain English
Everything a company owns had to be paid for somehow. It came from borrowing (liabilities) or from the owners (equity), including profits the business kept. That is it. What you have came from somewhere, and there are only two somewheres.
The Accounting Equation
Assets = Liabilities + Equity
Apple, fiscal 2025: $359.2B = $285.5B + $73.7B
The equation must always balance. That is not a goal. It is a rule, and it is why one of the three statements is called a balance sheet.
Watch It Work
A Coffee Shop’s First Month, in Ten Transactions
The book starts small on purpose. Here are ten everyday events from a coffee shop’s first month. Watch the three columns. After every event, assets still equal liabilities plus equity.
| After each transaction | Assets | Liabilities | Equity |
|---|---|---|---|
| 1. Owner invests $10,000 | 10,000 | 0 | 10,000 |
| 2. Bank lends $8,000 | 18,000 | 8,000 | 10,000 |
| 3. Buy equipment, $9,000 cash | 18,000 | 8,000 | 10,000 |
| 4. Buy $2,000 supplies on credit | 20,000 | 10,000 | 10,000 |
| 5. Sell $6,000 of coffee for cash | 26,000 | 10,000 | 16,000 |
| 6. Record $1,500 of supplies used | 24,500 | 10,000 | 14,500 |
| 7. Pay $1,200 rent | 23,300 | 10,000 | 13,300 |
| 8. Pay $1,800 wages | 21,500 | 10,000 | 11,500 |
| 9. Record $150 depreciation | 21,350 | 10,000 | 11,350 |
| 10. Pay $1,000 toward supplies bill | 20,350 | 9,000 | 11,350 |
Example from the book, in dollars.
The Method
How to Use the Equation in 5 Steps
Name the two things that move.
Every transaction touches at least two places. Buying a $9,000 machine with cash raises one asset and lowers another by the same amount.
Check which side each one sits on.
Cash, inventory, and equipment are assets. Loans and unpaid bills are liabilities. Owner money and kept profits are equity.
Confirm both sides still match.
If assets go up, either another asset went down, or liabilities or equity went up by the same amount. No exceptions.
Spot what is not an expense.
Buying equipment swaps cash for a machine. You still own the value, so it is not an expense. Using up supplies is.
Read a real balance sheet with it.
Total assets on top, liabilities and equity below, always equal. Try it on the Apple balance sheet guide.
Why This Matters to You
It is why nobody can honestly change one number on a financial statement by itself. If someone wants to bump up net income, the change has to land somewhere else too. Every number is tied to another. Once you see that, you start reading statements as one connected system instead of three lists.
Compare It
Same Equation, Very Different Balance Sheets
Apple and Microsoft both obey the equation. They just fill the two sides very differently. Apple leans on liabilities. Microsoft keeps a big equity base.
| Latest fiscal year | Apple | Microsoft |
|---|---|---|
| Total assets | $359B | $619B |
| Long-term debt | $78B | $40B |
| Total equity | $74B | $343B |
| Retained earnings | ($14B) | $238B |
Microsoft’s fiscal year ends in June, Apple’s in September. Figures from the book.
Same rule, two strategies. Apple has handed so much cash back to shareholders that its equity is small. That one fact explains a lot of Apple’s eye-popping ratios later on.
Double-Entry Bookkeeping
Why Does Every Transaction Have Two Sides?
Because the equation can never fall out of balance, every business event has to touch it in at least two places at once. That system is called double-entry bookkeeping, and it is roughly five hundred years old.
Borrow $8,000 from a bank, and cash goes up by $8,000 while the loan, a liability, goes up by $8,000. Both sides rise together. Sell $6,000 of coffee for cash, and cash rises by $6,000 while equity rises by $6,000, because profit belongs to the owners. Pay $1,200 of rent, and cash and equity both fall by $1,200.
Some events never touch equity at all. Paying $1,000 toward a supplier bill lowers cash and lowers accounts payable by the same amount. No expense, because the cost was already recorded when the supplies were used.
That is the whole machine. Learn to name the two sides of any event and you can follow how a company’s numbers got onto its statements, from a single latte to Apple’s billions.
Beginner Traps
Common Accounting Equation Mistakes
- Thinking a big purchase is always an expense.
- Forgetting that kept profit is part of equity.
- Changing one side of the equation without the other.
- Treating liabilities as bad and equity as good.
- Ignoring that depreciation lowers assets with no cash moving.
- Assuming the equation stops holding for big companies.
From the Book
The Whole Idea
The One Equation Behind Everything
Two Somewheres
That is the whole idea. What you have came from somewhere, and there are only two somewheres.
The coffee shop, all three statements it produces, and how the same machine runs Apple. It is all in the book.
Get the Book on Amazon →Keeping Your Own Books?
Your bookkeeping runs on this exact equation. Start with what bookkeeping is and how to set it up simply. If you want a professional reading your balance sheet each month, see fractional CFO services.
Beyond the Book
Need Help With Your Own Numbers?
Do it yourself, hand it off, or work through it together.
Business Plan Templates
The statements, prebuilt. A Word plan plus an Excel model for your industry.
See the Templates →Business Plan Writing
Hand it off. Dr. Paul writes the plan and the numbers that back it up.
See Plan Writing →Business Consulting
Straight answers on the numbers that run your business, from Dr. Paul.
See Consulting Options →FAQ
Accounting Equation Questions
What is the basic accounting equation?
Why must the accounting equation always balance?
Does the accounting equation work for big companies like Apple?
Keep Going
Related Guides
The equation is the base for every statement. See the full guide for the rest.
Written by Dr. Paul Borosky, DBA, MBA, business consultant, author, and adjunct finance instructor with an MBA focused in finance.
This page is for general educational purposes only. It is not investment, financial, tax, accounting, or legal advice, and nothing here is a recommendation to buy or sell any security. Apple and Microsoft figures come from their public filings as analyzed in the book. Apple and Microsoft are trademarks of their respective owners, and this page is not affiliated with or endorsed by either company.