Seasonal Cash Flow Smoothing Calculator
Size the cash reserve a seasonal business needs to cover its lean months and the amount to set aside each strong month to build it.
How it works
Monthly shortfall = max(0, fixed costs − low-season revenue) · Reserve = shortfall × low months · Set-aside = reserve ÷ (12 − low months)
A seasonal business does not have a revenue problem so much as a timing problem — strong months have to carry the lean ones. The reserve you need is simply the monthly gap between fixed costs and low-season revenue, multiplied by how many lean months you face. Spreading that target across your strong months gives a concrete monthly set-aside, turning a vague worry about the off-season into a savings rule you can actually follow.
Worked example
If four winter months each bring in $8,000 against $15,000 of fixed costs, you are $7,000 short a month, or $28,000 across the season. Building that over the eight strong months means banking $3,500 each — a disciplined transfer that keeps the doors open in the quiet stretch.
Frequently asked questions
How big should my cash reserve be?
For a seasonal business, size it to the total shortfall of your lean months plus a buffer, rather than a generic "three months of expenses" rule. This calculator ties the target directly to your own seasonality.
Where should I keep the reserve?
In a separate high-yield savings or money-market account, not your operating account. Physical separation stops peak-season cash from feeling like spendable profit.
What if peak season also disappoints?
Then the set-aside falls short and you draw on a line of credit for the gap. Building the reserve first still shrinks how much you need to borrow and what that borrowing costs.
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Educational estimate, not financial advice.