Every bookkeeper has had this experience. You send the monthly summary. Revenue is down 12% from last month. The client replies within minutes: "Is something wrong?"
Nothing is wrong. January is always slower than December. The business had an unusually strong October that skewed the comparison. The variance is normal. But the client doesn't know that — and if your email didn't address it, they filled in the gap with anxiety.
Explaining month-to-month variance clearly is one of the highest-value things a bookkeeper can do. It turns a number on a report into context the client can actually use.
Why Numbers Change Every Month
Before you can explain variance to a client, it helps to be clear in your own mind about the main causes.
Seasonality. Most businesses have predictable busy and slow periods. A landscaping company is slower in winter. A retail shop spikes in November and December. A tax preparer is flat all year except Q1. If you know the business well, seasonal variance is expected and explainable.
Timing differences. A large invoice paid in March that was earned in February will make March look stronger than it was. Expenses billed annually hit the month they're charged. Payroll timing can shift by a day or two and affect the period. These are timing artefacts, not business changes.
One-off items. Equipment purchases, legal fees, a one-time marketing spend — these inflate expenses in the month they occur without reflecting the ongoing cost structure of the business. They need to be called out explicitly.
Genuine business changes. Sometimes variance reflects something real — a lost client, a new product line gaining traction, a supplier price increase. These deserve more attention in the monthly summary.
The Language That Works
Most clients don't have an accounting background. They understand plain English, not accounting terminology. A few phrases that translate well:
Instead of "revenue decreased due to timing of receivables collections" — try "two large invoices from March work were paid in April, so they'll show up next month instead."
Instead of "operating expenses were elevated due to non-recurring items" — try "there was a one-off legal fee this month that won't repeat — without it, expenses were in line with last month."
Instead of "gross margin contracted 3 points" — try "for every dollar of revenue, you kept slightly less after direct costs than last month — mainly because materials prices went up."
The goal is not to dumb it down. It's to translate it. Clients are often smart, capable people who simply haven't spent years reading P&L statements.
What to Include in the Monthly Summary
A good monthly summary email that handles variance well covers four things:
The headline number. Revenue, net profit, or whatever the client cares most about — stated plainly with the direction and percentage change.
The reason for any significant change. If something moved more than 10% in either direction, explain why. One sentence is usually enough.
Anything unusual. One-off items, timing differences, anything that shouldn't be compared directly to last month.
What to watch next month. If you can see something coming — a slow period, a large expense, a seasonal uptick — mention it. Clients value foresight more than they value hindsight.
When the Numbers Are Actually Bad
Sometimes the variance isn't timing or seasonality. Sometimes revenue really is declining, or expenses are genuinely out of control, or margins are compressing in a way that's unsustainable.
This is where bookkeepers add the most value — and where the instinct to soften the message does the client a disservice.
Report it plainly. "Revenue has declined three months in a row — down 8%, 11%, and 14% respectively. This pattern is worth paying attention to." That is more useful than burying the trend in hedging language.
You don't need to diagnose the business problem. That's not your job. Your job is to make sure the client sees the numbers clearly. What they do with that information is their decision.
Anomaly Detection as a Safety Net
One of the practical challenges of writing monthly summaries for 10 or 15 clients is that it's hard to catch every unusual pattern manually. You're moving quickly, the numbers blur together, and something that would be obvious if you stared at it for ten minutes gets missed in a 15-minute turnaround.
Tools that flag anomalies automatically — sudden revenue spikes, expense changes, revenue concentration in a single client — help ensure nothing slips through. The bookkeeper still writes the explanation. The tool just makes sure the right questions get asked.
The Takeaway
Month-to-month variance is normal. Clients who understand that are calmer, more trusting, and easier to work with. The bookkeeper who explains the numbers clearly — not just reports them — is the one who keeps clients for years.
The monthly summary email is your best tool for doing that. It takes time to write well. But it's the most visible thing you produce each month, and the thing clients remember most.
Figurenote generates plain-English monthly summary emails from your QuickBooks data in seconds — including flagging unusual months automatically. Free for one client, no credit card required.