Cash flow versus budget, and which one tells you whether you're okay

Cash flow tells you whether you're okay. A budget tells you where to change something. Cash flow is what actually happened: money in against money out over a period, with the difference as the result. A budget is what you planned to happen, category by category. A positive cash flow three months in a row means the household is okay whatever the budget says, and a negative one means it isn't, however well the categories behave. Track cash flow first, for three months, and build the budget from what it shows.

Two questions, two tools

The two are often confused because both involve the same transactions. Cash flow adds them up. A budget compares them with a plan. Only the first can tell you the plan was wrong.

Cash flow is what happened

Income is money that arrived and is yours: pay, freelance deposits, interest, a tax refund. Spending is money that left: purchases, bills, loan payments. Movements between your own accounts, such as a transfer to savings or a credit card payment, are neither, and leaving them out is the whole skill. See How to stop credit card payments and transfers from double-counting for the rule.

Income minus spending is net cash flow. Over one month it is a fact about that month. Over three months it is a fact about you, and the share of income you kept, which is net cash flow divided by income, is the single figure that says whether the finances are getting stronger. Cash flow is the "okay" measure because it is the only number that has to stay positive over time. A budget can be perfect in every category and cash flow still negative, if the amounts were set too high.

A budget is what you planned

A budget is an amount per category for the month ahead, and it earns its keep in one way: by saying which category to look at when the month runs short. It is only as good as its amounts, which is why a budget set from guesses tells you nothing and a budget set from three months of cash flow tells you a lot.

A budget also can't say whether the whole plan works unless its amounts are added up and set beside income. That sum, income minus everything budgeted, is the budget's own version of cash flow, and it is the number to watch while setting amounts.

Read them together, step by step

1. Compute cash flow for the last three months: income, spending, and the net for each month.
2. Decide what the budget's job is. If the net was negative in two of the three months, the budget's job is to find the categories to cut. If it was positive, the budget's job is to hold the level and give the surplus a destination.
3. Set the budget's amounts from the categories' three-month averages. See How to set budget amounts when you have no idea what you spend.
4. Each month, check cash flow first, then the categories. The net says whether the month was okay; the categories say why.
5. When the two disagree, reconcile them. A budget that reads under in every category alongside a negative cash flow means a category is missing, income came in low, or a movement was counted as spending.

A worked example

Three months for a household with take-home pay of $5,400 a month and a $1,500 tax refund in the third.

The budget view of month 2 showed groceries $20 under, dining out $15 under, and every other category on plan, and the month still ran $320 short, because a $680 car repair had no category and no amount. The budget said fine; cash flow said not fine; the reconciliation found the missing line, and the next budget has a car maintenance category with a monthly share.

Over three months the household kept $1,530, about 8.6% of income, which reads as comfortable. Without the refund it kept $30 on $16,200, which is 0.2%. The refund is real money and a bad month to judge by. The honest reading is that this household is okay by a hair, and the budget's job for the next quarter is to find $150 a month that stays.

When the two disagree

Budget green, cash flow negative. A category is missing, a non-monthly bill landed, income came in below plan, or a transfer was counted as spending. Find which, because the budget is lying by omission.

Budget red, cash flow positive. The amounts are tighter than reality, or income came in above plan. Reset the amounts to what the cash flow says was actually spent, and the budget will start telling the truth about where the surplus goes.

Both negative. The problem is bigger than any category, and it lives on the committed side: rent, the car, insurance, debt. See How much of the month is already spoken for for how to size it.

Common mistakes

• Counting transfers and card payments in cash flow, which makes every month look worse than it was.
• Judging one month. A refund, a bonus, a car repair, or a three-paycheck month makes any single month unrepresentative.
• Budgeting before measuring. The amounts are guesses, and the budget measures how wrong the guesses were rather than how the money went.
• Treating a windfall month as the norm. The month with the refund is the one that feels okay and the one that proves least.
• A budget with no income line, so the amounts never get added up against anything.
• Ignoring cash flow because the categories look fine. Fine categories with a negative net means the budget is missing something.

Common questions

Which should I look at first each month? Cash flow. The net for the month says whether you were okay, in one number, before any category is opened. Then the categories say why, and the budget says what to change.

What counts as good cash flow? Positive, consistently, over three or more months. The share of income kept matters more than the dollar amount, because it is what makes two households comparable, and the trend in that share matters more than any one reading.

Can I skip the budget if my cash flow is positive? For a while. A positive net with no budget is a household that is okay and doesn't know why, and the budget is what you reach for when the net turns negative or when you want the surplus to go somewhere on purpose.

Do pending transactions count in cash flow? Yes. A purchase that hasn't posted yet is money you have spent, and leaving it out makes the month look better than it is until the day it posts.

How do loan payments and investments count? A loan payment is spending in cash flow, because the cash left, even though the principal part leaves net worth unchanged. Money moved into a brokerage or savings account you track is a movement into an asset, not spending, and it shows up as the month's net rather than as a category.

How Zypper handles this

Zypper keeps the two questions on two pages. The cash flow page charts your income against your spending over any period you choose, this month, last quarter, or the year, and breaks the difference down by category, by category group, or by merchant, with each row opening a chart and the transactions behind it. Movements between your own accounts don't count as income or spending by default, and the page's settings let you choose how transfers are treated. The budget page holds the plan: an amount per category, what you have spent against it, and Left to budget, your expected income minus everything you have budgeted, which is the budget's own answer to whether the plan adds up. A transaction counts on both pages as soon as it arrives, pending or posted, so the month's figures never wait for a statement. See Cash flow and Creating your budget for the details, or get started with Zypper to see your own three months.