Debits and Credits: The One Rule That Never Changes

A debit is the left side of an accounting entry and a credit is the right side. Neither one means increase and neither means decrease. The effect of a debit depends entirely on which kind of account it lands in: it raises assets and expenses, and it lowers liabilities, equity and revenue. A credit does the opposite. Every transaction is written with at least one of each, and the two sides carry equal amounts.

The idea underneath is this. Every transaction is an exchange, and an exchange has two ends. Something came in and something went out, or something arrived now against a promise to settle later. Debit and credit are simply the names of those two ends, written as two columns side by side. Fixing them as left and right rather than as plus and minus is the move that lets one convention describe cash, a supplier bill, a delivery van and a month of wages without once changing what the words mean.

The rest of this guide runs from the two words themselves, through the five kinds of account and the ten-cell grid that settles every entry ever written, to five transactions from one business's year written out in full and the size of the hole left when somebody writes only one side of an entry.

What does a debit actually mean, and what does a credit mean?

A small shop at closing time will often have a ruled notebook with a line drawn down the middle. Money that came in gets written on one side of the line. Money that went out gets written on the other. Nobody standing at that counter thinks the left of the line means good and the right means bad. Left and right are two sides of one sheet, and the line is there so that two different kinds of thing never end up muddled in a single column.

A debitThe left hand column of an accounting entry. The word comes from the Latin for what is owed, but in modern books it carries no meaning beyond the position of the column. is the left side of an entry and a creditThe right hand column of an accounting entry. Like debit, it names a position in the entry and nothing else, which is why it can describe money coming in on one set of books and going out on another. is the right side, and that is the entire definition. Not an increase. Not a decrease. Not money in and not money out. Two words for two columns, borrowed from Latin several centuries ago and kept ever since because they are shorter than "left hand column" and much harder to muddle than a plus sign and a minus sign scribbled at speed. Meera Rao keeps the books three days a week at Anjani Stationers, an invented maker of school notebooks, and she never decides whether an amount is a debit by asking whether it is good news. She decides it by asking which column the amount belongs in, and everything below is how she knows.

The everyday proof that the two words carry no direction of their own is a bank message. A bank sends word that an account has been credited with a salary. The account holder feels richer, so credit begins to feel like more. Then the same person opens a private record of that same money and finds that the very same salary has to be written as a debit to cash. Both records are correct. The bank was writing its own books. To a bank, the money sitting in a customer's account is money the bank owes the customer; money owed is a liability, and a credit raises a liability. In the customer's own books the same money is an asset, and an asset rises with a debit. One event, two sets of books, two opposite columns, and nobody made a mistake anywhere.

Why does a debit not simply mean an increase?

Almost everyone builds the same shortcut on their first day, and it is not a stupid one. Debit equals increase. The shortcut is right about cash. It is right about the stock of paper in the store, right about the delivery van and the printing machine, and right about every expense the business will ever record. Cash, stock, machines and expenses are four of the five things a beginner meets most often, so the shortcut survives dozens of entries and hardens into a habit long before anything contradicts it.

The shortcut fails the first time a liability appears, and it fails in a way that feels completely correct while the mistake is being made. Anjani Stationers buys Rs 4,00,000 of paper on credit. The pile of paper grew, and so did the pile of unpaid invoices on the desk, so taking on that bill feels like an increase. Write it as a debit to payables, though, and the payables balance of Rs 18,00,000 falls to Rs 14,00,000. Read out loud, that says Anjani Stationers now owes its paper suppliers Rs 4,00,000 less than it did that morning. Nothing remotely like that happened. A debit to payables is what paying a supplier looks like, and no supplier was paid.

One word with two directions is why plus and minus were never used. A plus sign would have to mean one thing on a cash record and the opposite thing on a supplier record, and a symbol that changes meaning depending on where it lands is worse than useless in a system where thousands of entries are written by different hands. Left and right do not have that problem. A sheet has a left side and a right side whatever is written on it, in any month, in any business, in any language. The direction is not in the word. The direction comes entirely from the account the amount lands in, so the next thing to learn is what kinds of account there are.

What are the five kinds of account, and where does each one sit?

Every accountOne named record inside the books, holding every amount that has ever moved through one thing: one account for cash, one for what schools owe, one for wages, and so on. a business keeps is one of exactly five kinds, and sorting an account into the right kind is the only judgement anyone has to make before the rule takes over and does the rest.

An asset is something the business has that will bring in money or be used up in earning it: Anjani Stationers' cash of Rs 7,00,000, the Rs 75,00,000 the schools still owe after the provision, Rs 22,00,000 of paper and finished notebooks in the store, the delivery van and the printing machine. A liability is something the business owes to someone else: Rs 18,00,000 to paper suppliers and Rs 3,00,000 of March salaries not yet handed over. Equity is what would be left for the people who put money into the business if every asset were turned into cash and every liability settled; for Anjani Stationers at the year end that is Rs 1,12,00,000. Revenue is what the business earned by doing the thing it exists to do, Rs 2,40,00,000 of notebooks billed to schools. An expense is what it used up in earning that revenue: paper, wages, rent, insurance, the wearing out of the machine.

Now put those five on a line. Assets sit on one side. Liabilities and equity sit on the other. Between them they explain where every single asset came from: either somebody outside the business supplied it and is owed, or the people who put money in supplied it and are entitled to what is left. Assets on one side and liabilities and equity on the other is the accounting equationThe statement that everything a business holds must equal everything it owes plus everything left over for the people who funded it. Assets on one side, liabilities and equity on the other., and revenue and expense are simply the two accounts through which equity changes during a year. An expense reduces what the funders end up with, so it behaves like the assets side. Revenue increases what they end up with, so it behaves like the equity side.

Assets and expenses live on the left of the equation, and liabilities, equity and revenue live on the right, and that position is the only thing that decides how each of the five behaves. There is nothing else to memorise. Once an account is sorted onto a side, its behaviour under a debit and under a credit follows without any further thought.

Adding up the two sides is a check that the sorting was done correctly. Anjani Stationers' assets of Rs 1,33,00,000 plus expenses of Rs 2,02,00,000 come to Rs 3,35,00,000. Liabilities of Rs 21,00,000 plus the Rs 74,00,000 of equity the business started the year with plus revenue of Rs 2,40,00,000 also come to Rs 3,35,00,000. If a sorting produces two different totals, an account has been put on the wrong side.

How does each of the five behave under a debit and under a credit?

People expect the behaviour of the five kinds to be the hard part, and it is not: there are only two answers and they repeat. The group on the left of the equation is assets and expenses. A debit raises them and a credit lowers them. The group on the right is liabilities, equity and revenue. A debit lowers them and a credit raises them. Five account types multiplied by two columns is ten cells, and eight of those ten cells are settled the moment the side an account sits on is known.

The complete rule, with nothing left over, is that a debit raises anything on the left of the equation and lowers anything on the right, and a credit does exactly the reverse. The grid below rewards two readings. The first asks what a debit does; the second asks what would have to be done to an account to make it go up. Both readings matter. In practice the direction wanted is already known, and the hunt is for the column that produces it.

In rupees, the whole rule reads like this. Payables stand at Rs 18,00,000; a debit of Rs 4,00,000 leaves them at Rs 14,00,000 and the same credit would leave them at Rs 22,00,000. Cash of Rs 7,00,000 goes the other way: a debit takes it to Rs 11,00,000 and a credit takes it to Rs 3,00,000. With the five set side by side, the two groups separate cleanly.

How do I know which side a transaction goes on?

Two questions settle it, always, and they are asked in a fixed order: what did the business receive, and what did it give up or promise in return? The answer to the first question goes on the left. The answer to the second goes on the right. The method is received on the left and given up on the right, and it survives every transaction that arises, including the awkward ones where nothing physical moves at all.

Name what came in and name what went out, in that order, and the two names are already the two sides of the entry. Think of a household buying a second hand scooter with money borrowed from a cousin. A scooter arrived, so the scooter goes on the left. A promise to repay the cousin was given up, so the promise goes on the right. Nobody has to remember a rule about scooters. The same two questions run a Rs 6,00,000 invoice to a school. Anjani Stationers received a right to be paid Rs 6,00,000, and a right to be paid is an asset, so receivables are debited. The business gave up the notebooks and the trade that goes with them, and trade given up is revenue earned, so revenue is credited. The school has not paid, so no cash is involved at any point.

What does one real transaction look like when it is written down properly?

Take five transactions from Anjani Stationers' year one and write each of them out in full. The five are ordinary: a school invoiced, paper bought, a school paying, wages paid, and the year's wear on the van and the machine recorded. Every one takes the identical written shape. The debited account is named first, hard against the margin. The credited account is named on the next line, indented so the eye can see at a glance which is which. The debit amount goes in the left money column and the credit amount in the right. The written form is a journal entryOne transaction written out in its standard form: the debited account first, the credited account indented under it, both amounts in their own columns, and a short line saying what happened., and it has looked much the same for a very long time.

Now look hard at the third of those entries, the one that teaches something the other four do not. A school pays Rs 5,00,000 against an invoice raised months earlier. Cash is debited and receivables are credited. Both accounts are assets, so one asset went up and another went down by the same amount, and Anjani Stationers ended that day owning exactly what it had owned that morning.

Collecting Rs 5,00,000 from a school makes the business no richer at all. The revenue was already recorded when the notebooks were delivered, and all that has happened since is a swap of one asset for another. The collection entry quietly explains why a business can be busy collecting money all month and report no extra profit for it, and it is worth sitting with. A collection is a relief, and relief is a real and important thing when suppliers are waiting, but it is not a gain.

The fifth entry has a different oddity worth naming. Depreciation of Rs 5,00,000 debits an expense and credits accumulated depreciationA running total of how much of an asset's original cost has been written off so far. It is held separately from the cost, so the books keep showing both what the thing cost and how much has been used up.. Accumulated depreciation sits against the van and the machine and reduces what they are carried at. The van cost Rs 12,00,000 and is now carried at Rs 6,00,000; the machine cost Rs 30,00,000 and is carried at Rs 21,00,000. Both assets were bought and paid for years earlier, so no cheque was written on the day that entry was made. The entry moves a slice of that old payment into this year's expenses and touches the bank account not at all.

What happens if the two sides do not agree?

Every entry is written with at least one debit and at least one credit, and the amounts on the two sides are equal. Some entries touch four or five accounts at once, and that is perfectly normal: a salary payment that also deducts tax and a staff advance has one debit and three credits. One thing never changes: the total written on the left equals the total written on the right for that entry.

An entry with only one side written leaves the two columns of the whole set of books unequal, and that inequality is how the mistake announces itself. Meera Rao's month-end routine is to add up every debit in the ledgerThe full set of accounts, with every amount that has ever moved through each one gathered in its own place, so a person can look up cash or payables and see the whole history in one column pair. and every credit, and put the two totals side by side. The listing is called a trial balanceA list of every account and its balance, with all the debit balances in one column and all the credit balances in another, prepared to see whether the two columns come to the same total.. If the two totals differ, at least one entry has been written wrong, and the difference is the first clue about which one. Why the system was built so that the two columns must agree in the first place, and what that agreement is worth to somebody reading the books, is set out under double-entry bookkeeping; at month end the disagreement is only the alarm that announces an entry went in badly.

What does a lender or an analyst actually do with debits and credits?

Nobody outside a bookkeeping room writes journal entries, so it is fair to ask why a person reading a set of accounts should care which column an amount went in. The answer is that the two columns of an account are a record of two different kinds of event, and reading them apart is how a reader finds out what a business actually did during a year rather than what it ended up with.

An account read by its two columns gives the story; read only by its closing balance it gives the ending. Anjani Stationers' cash account is the plain case. The debit side holds the opening balance of Rs 8,00,000 and Rs 1,92,00,000 collected from schools. The credit side holds Rs 1,26,00,000 paid to paper suppliers, Rs 51,00,000 of wages, Rs 12,00,000 of rent and Rs 4,00,000 of insurance. The two sides come to Rs 2,00,00,000 and Rs 1,93,00,000, and the Rs 7,00,000 difference is the closing cash. A reader who sees only Rs 7,00,000 knows nothing about a year in which Rs 2,00,00,000 passed through the account.

Three readers use the same habit differently. A lender looking at the payables account reads the credit side as new bills arriving and the debit side as bills being settled, and a month where credits ran far ahead of debits means the business has been stretching its suppliers to fund itself. An analyst looking at the provision against the Sunrise Public School group's overdue Rs 6,00,000, set aside in case that debt is never paid, notes that the Rs 3,00,000 charge was a debit to an expense and a credit set against school dues. The pairing tells them profit fell by Rs 3,00,000 and not a rupee of cash moved. And Meera Rao, closing a month, reads a debit balance sitting in an account that should carry a credit balance as a signal that something has been posted the wrong way round, before anybody outside ever sees the figure.

Almost nothing in finance is this portable. The debit and credit convention is the same everywhere. A debit is the left side in Mumbai, in Manchester and in Manila, in every language and under every set of national rules, and it has been for centuries. Countries differ only on whether a business is legally required to keep books at all and in what form; in India that is a matter of company law administered by the Ministry of Corporate Affairs. The left and the right do not vary anywhere.

Anjani Stationers Private Limited, Anjani Kulkarni, Meera Rao and the Sunrise Public School group are invented.
Educational material. Not advice on any investment, tax, budget or market position.