Reading your P&L: what to check every month
In short
Read your P&L in the same order every month: revenue, gross margin, overheads, then net profit, each compared with last month and budget. Finish by writing down up to three pricing, job cost or spending decisions.
- Read the P&L in a fixed order: revenue, gross margin, overheads, then net profit.
- Compare every line with last month and with budget, because one month alone says little.
- Gross margin is the percentage that shows whether pricing and job costs are working.
- If gross profit is below total overheads in a month, the business made a loss however busy it was.
- End each review by writing down no more than three decisions with an owner and a date.
Most owners glance at the bottom line and move on. This guide gives a fixed monthly routine for reading a profit and loss statement: revenue, gross margin, overheads, then net profit, compared with last month and budget, ending in three clear decisions.
Read a profit and loss statement in the same fixed order every month: revenue first, then gross margin, then overheads, and net profit last, with each line compared against last month and against budget. Revenue tells you how much you sold, gross margin tells you whether the work itself made money, and net profit tells you what survived your overheads. If gross margin is healthy but net profit is thin, overheads are the problem. If gross margin is thin, pricing or job costs are.
Most owners of small businesses look at the bottom line first, feel good or bad, and close the file. That wastes the report. The bottom line is the result of three separate decisions: what you charge, what jobs cost to deliver, and what you spend to keep the business running. A profit and loss statement lists all three, but only if you read it in sequence.
The routine below takes about 30 minutes once your accountant or bookkeeping software has closed the month. It works for any business that sells jobs, projects or orders.
Why the reading order matters
A P&L is built as a chain of subtractions. Revenue minus cost of sales gives gross profit. Gross profit minus operating expenses gives operating profit. After interest, other items and tax, you reach net profit. Because each subtotal depends on the one above it, a problem near the top contaminates everything below.
Reading bottom-up causes two common mistakes. An owner sees a poor net profit and cuts overheads, when the real leak was a job type quoted too cheaply. Or an owner sees a decent net profit and relaxes, when revenue is falling and a one-off item flattered the result. A fixed order forces you to ask the right question at each level before moving on.
Comparison is the second half of the habit. A single month in isolation says little. Against last month it shows direction, and against budget it shows whether the plan you made is still the plan you are living. Accounting guidance from sources such as Xero and the Oregon Small Business Development Center Network makes the same point: reviewing the P&L regularly lets you spot rising costs and falling margins before they reach your bank balance.
Check revenue against last month and budget
Start with the top line. Note total revenue, then compare it with the previous month and with the budget figure. Do not stop at the total. If your report splits revenue by product, service or customer type, look at which line moved. A flat total can hide one stream growing while another shrinks. Also check timing: revenue recognized in the month reflects invoices raised, not cash received, so a late invoice at month end will understate revenue even though the work was done.
Confirm revenue matches what you invoiced
Before trusting the number, check it against your own records. Total the invoices raised in the month and compare with the P&L revenue line. A gap usually means a missed invoice, a credit note, or work delivered but not yet billed. Fixing that is a revenue decision, and it is much cheaper to find in week one of the next month than at year end.
Calculate gross margin as a percentage
Subtract cost of sales (materials, subcontractors, direct labor, goods bought for resale) from revenue, then divide by revenue. For example, revenue of 100,000 with cost of sales of 62,000 gives gross profit of 38,000 and a gross margin of 38 percent. The percentage matters more than the amount, because it is the figure you can compare month to month even when volumes change.
Investigate any gross margin movement
A move of even one or two points deserves a reason. Ask whether supplier prices rose, whether discounts crept into quotes, whether a job overran its labor allowance, or whether the mix shifted toward lower-margin work. This is where the P&L turns into decisions about pricing and job costs. If margin fell, pull your largest jobs and compare quoted cost with actual cost job by job.
Review overheads line by line
Now read operating expenses: rent, software, vehicles, insurance, marketing, admin wages. Compare each line with last month and budget, and flag anything that moved more than a threshold you set, for example 10 percent. Distinguish between the fixed costs that barely change and the variable ones that creep, such as subscriptions, fuel and card fees. Overheads are the only section where cutting is usually a pure saving, so check them with care but only after gross margin is understood.
Read net profit and operating profit together
Only now look at the bottom. Calculate net profit as a percentage of revenue and compare it with last month and budget. Check for one-off items such as an asset sale, a grant, a bad debt write-off or a tax adjustment, which can make the month look better or worse than the underlying trading. Operating profit, before interest and tax, is the cleaner measure of how the business itself performed.
Write down three decisions
Finish by recording no more than three actions with an owner and a date. Examples: raise prices on one product line, re-quote a job type with a higher labor allowance, cancel an unused subscription. A P&L review that ends without a decision has only been a read. Keep the notes in one place so next month you can see whether the actions worked.
Which lines tell you the business is really making money
Two lines carry most of the answer. Gross margin shows whether each sale earns enough to contribute to your running costs. Net profit shows whether, after those costs, anything is left. A business can have healthy revenue and still lose money because gross margin sits below what overheads require.
A quick test is to work out your break-even gross profit: your monthly overheads. If gross profit in a month is below total overheads, you made a loss however busy you were. If you also know your typical margin, you can divide overheads by margin to find the revenue you need each month.
Remember what the P&L does not show. It is not a cash report, so profit does not equal money in the bank. Unpaid customer invoices, stock purchases and loan repayments sit on the balance sheet and cash flow statement. Treat the P&L as the profitability view and pair it with a cash check, particularly if customers pay slowly.
Getting the numbers to be right in the first place
A P&L is only as good as the records feeding it. Revenue is only right if invoices are raised promptly, and gross margin is only meaningful if costs are coded to the job they belong to. If supplier bills land in one general cost bucket, the accounts will show total spend but not which jobs ate the margin.
That is where operational records help. Keeping a cost and sales figure against every order in a jobs record lets you see margin per job before the month is closed, so the P&L confirms what you already know. Raising invoices at the point work is completed or a milestone is reached keeps revenue in the right month. And a reporting view of revenue and margin by customer or job type gives you the breakdown that a standard accounting P&L often lacks. None of this replaces your accountant or your accounting software; it gives them cleaner inputs and gives you earlier warning.
Common mistakes when reading a P&L
The first is reading it irregularly. Looking quarterly means a margin slide that began in month one runs for three months before you see it. The second is comparing only with the same month last year, which ignores recent changes. The third is treating owner pay inconsistently: if your own wages are missing from the statement, net profit is overstated. The fourth is ignoring the cost of sales classification. Some costs sit in overheads that really belong against jobs, which makes gross margin look better than it is. Ask your accountant how direct labor and subcontractors are treated and keep it consistent.
Finally, do not try to read every line every month. Fix the order, fix the comparisons and apply a threshold. The value comes from the repetition, because after three or four months you will know what normal looks like and exceptions will stand out in minutes.
Common questions
Sources
- How to Read a Profit and Loss StatementOregon Small Business Development Center Network · accessed 2026-10-31
- How to read a profit and loss statement: a guide for business ownersXero UK · accessed 2026-10-31