Seasonal Revenue Planner
Spread your annual revenue across your seasonal pattern and see the cash trough coming — months before it hits.
Written by Dorothy Ibrahim, 10+ years in banking & finance
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How we calculate this
Seasonal businesses rarely fail in the busy season — they fail in the trough, months after the money stopped. This planner spreads your annual revenue across a 12-month seasonality index, subtracts variable and fixed costs to get monthly profit, and runs the cumulative cash balance forward to find the trough: the month your cash bottoms out, how deep it goes, and how many months run below break-even. Seeing the trough in advance is what makes it fundable.
The formulas
- Monthly revenue
- annual revenue × (that month’s index weight ÷ sum of all 12 weights)Weights are relative, so only the shape matters — 2.0 vs 1.0 means double an average month.
- Monthly profit
- monthly revenue × (1 − variable-cost %) − monthly fixed costs
- Cumulative cash
- opening cash + running total of monthly profits
- Monthly break-even revenue
- monthly fixed costs ÷ (1 − variable-cost %)Months whose revenue falls below this are flagged; undefined when variable costs reach 100% of revenue.
- Reserve needed
- the depth of the trough below zero (zero if cash never goes negative)
Worked example
- Say annual revenue is $600,000 with a summer-heavy pattern — index weight 2.0 in months 5–8, 1.0 in the other eight months — fixed costs of $30,000/month, variable costs at 40% of revenue, and $25,000 of opening cash.
- The weights sum to 16, so an off-season month brings in $600,000 × 1⁄16 = $37,500 and a peak month $600,000 × 2⁄16 = $75,000.
- Monthly break-even revenue = $30,000 ÷ (1 − 0.40) = $50,000 — so all 8 off-season months run below break-even, each losing $37,500 × 0.60 − $30,000 = −$7,500, while peak months earn $75,000 × 0.60 − $30,000 = +$15,000.
- Running the cash forward from $25,000: three losing months take it to $2,500, and month 4 pushes it to −$5,000 — the trough — before the summer months rebuild it to $55,000 by month 8; it ends the year back at $25,000.
- The year is profitable overall, but cash still goes $5,000 negative in month 4 — so the tool calls for a $5,000 reserve (or a line of credit) in place before the slow season, not during it.
Rates, benchmarks & sources
- Monthly break-even revenue = fixed costs ÷ (1 − variable-cost %); profit = revenue × contribution margin − fixed costs. — Standard contribution-margin arithmetic
- Arrange reserves or a line of credit before the trough — lenders approve faster when you do not yet need the cash. — Industry rule of thumb
Figures current as of 2026-07-02. See our methodology & editorial standards for how constants are versioned and verified.
What this tool doesn’t model
- Revenue equals cash in this model — it ignores collection lag, so if you invoice on terms, real cash arrives later than modeled and the true trough is deeper and later than shown.
- Fixed costs are spread evenly; lumpy items like quarterly taxes, annual insurance, or pre-season inventory buys land in specific months and can move the trough. The 12-Month Cash Flow calculator handles month-specific items.
- The seasonality index is your estimate — a couple of years of actual monthly sales make a far better index than a guessed pattern, and small changes in shape change the trough.
- It assumes the same variable-cost percentage every month, though off-season discounting or peak-season overtime can shift margins seasonally.
Frequently asked questions
How do I pick my seasonality index weights?
Use real history if you have it: take two or three years of monthly sales, average each calendar month, and divide by the overall monthly average — that ratio is the weight (1.0 = average, 2.0 = double, 0.5 = half). Only the shape matters, since the tool normalizes the weights before spreading your annual revenue. Without history, sketch the pattern you expect and refine it as actual months come in.
How can my business be profitable for the year and still run out of cash?
Because profit is annual and cash is sequential. The losing months arrive in a row, and if their combined drain exceeds your opening cash, you hit zero mid-year — long before the profitable season shows up to repay it. In the worked example, a business earning positive profit over twelve months still goes $5,000 negative in month 4. Timing, not profitability, is what the trough measures.
What should I do about a projected cash trough?
The usual playbook is to pre-fund it or pre-arrange credit — before the slow season, when the numbers still look good. That can mean building the reserve to the trough depth during peak months, arranging a line of credit early (the rule of thumb: lenders approve faster when you do not yet need the money), smoothing revenue with off-season offers or annual prepay deals, or shifting controllable expenses out of the trough months.
What does "months below break-even" actually tell me?
It counts the months whose revenue falls short of covering fixed costs after variable costs are paid — months where the business loses money by design, not by accident. A seasonal business can healthily run several such months if the peak season funds them; the number matters because each below-break-even month drains the cushion, and the count times the typical monthly loss approximates how much cushion the slow season consumes.
How is this different from the 12-Month Cash Flow calculator?
This planner is top-down: it starts from one annual revenue figure and a seasonal shape, and derives monthly profit and cash — fastest when you know the year and the pattern but not the month-by-month detail. The Cash Flow calculator is bottom-up: you enter each month’s actual inflows and outflows, including one-time items. Many owners sketch the year here, then move to the cash-flow grid as real numbers firm up.
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themoneysheet provides educational estimates, not financial, tax, or legal advice. Figures use published rates and formulas current as of the date shown, but your situation may differ. Consult a qualified professional (CPA, attorney, or licensed advisor) before making financial decisions.