Business Seasonality: How to Prepare for the Low Season

Preparing for the low season takes three steps: identify seasonality from the figures of past years, calculate what the weak months cost, and set that amount aside in the months when revenue is higher. Then fixed costs get covered throughout the whole year.

Let's go through how to calculate a seasonality index, how a reserve amount comes out of it, and what else, besides a reserve, evens out the year. We'll run every calculation on one example: a coffee shop near a park.

In plain terms. Picture a gardener who harvests apples once a year but buys bread every week. To have bread every week, the harvest gets spread across the whole year: some is sold right away, some goes into storage and gets stretched out. A seasonal business works the same way: revenue arrives unevenly while costs arrive evenly, so the income from strong months gets spread across the whole year.

What seasonality is

Seasonality is a rise and fall in revenue that repeats year after year in the same months. The causes vary: weather, holidays, the school year, vacations, the dates when customers receive their own income.

What separates seasonality from a random fluctuation is repetition. A dip in January that repeats three Januaries in a row points to a season. A dip in March in just one year is most likely tied to an event of that year: the advertising changed, prices changed, a new competitor opened nearby.

Fixed costs don't depend on the season: rent, payroll, and subscriptions are the same every month. That's why the difference between a strong and a weak month shows up in the account balance.

How to calculate a seasonality index

Seasonality can be measured with a single indicator called the seasonality index. It compares each month against an ordinary month of the year.

Month's seasonality index = Month's revenue ÷ Average monthly revenue × 100%

An index of 100% means an ordinary month: a value above 100% indicates a stronger month, below 100% a weaker one.

Picture Maksym. He runs a small coffee shop near a park. The shop's fixed costs (rent, payroll, subscriptions, taxes, and contributions) come to $12,000 a month. Gross margin after direct costs for coffee, milk, and pastries equals 50%. Substitute the tax and contribution rates that apply where you are. Maksym wrote out last year's revenue month by month.

Step one: take the revenue for each month. The index needs a full series of twelve months. Ideally, take two or three years and average the same months. If you only have one year, the index will be approximate: one-off events could have happened that year. In the example there's one year, and total revenue comes to $360,000.

Step two: calculate average monthly revenue. $360,000 ÷ 12 = $30,000. That's the ordinary month we compare everything else against.

Step three: divide each month's revenue by the average. For January, that's $18,000 ÷ $30,000 = 0.6, which is an index of 60%. Each month is calculated the same way.

Step four: read the result. Maksym sees a peak in July (160%), three weak months (January, February, and November, 60% each), and three ordinary months: April, September, and December.

What the low season costs

The index shows which months are weak. What that costs is shown by the break-even point: the revenue at which a month lands at zero.

Break-even point = Fixed costs ÷ Gross margin

Step one: calculate the break-even point. $12,000 ÷ 0.5 = $24,000. In index terms, that's 80%: if the index is lower, the month is in the red, if higher, in the black.

Step two: calculate each month's result. Multiply revenue by gross margin and subtract fixed costs. For January: $18,000 × 0.5 = $9,000, minus $12,000, gives −$3,000. For July: $48,000 × 0.5 = $24,000, minus $12,000, gives +$12,000.

Step three: add up the shortfalls. January, February, and November give −$3,000 each, −$9,000 in total. March and October sit exactly at zero.

Step four: compare with the surplus. Seven months in the black give +$45,000. The year as a whole finishes at +$36,000.

Now it's clear that the year is in the black, while three months are in the red. If the summer surplus gets spent in the summer, the account will be $3,000 short in January. The reserve covers that difference.

Low-season reserve = Sum of shortfalls in months below the break-even point

In the example, the reserve equals $9,000. A guideline: a cushion for deviations is usually added on top of the calculated amount, because next year won't be a copy of the last. How much depends on how similar past years have been. There's no standard for it.

Why look at the whole year? A single month in the red doesn't mean the business is unprofitable. Likewise, a strong month doesn't mean all the money can be spent. The reserve combines these two facts: it moves part of the strong months' surplus into the weak months.

What else evens out the year

The reserve covers the shortfall, but the shortfall itself can shrink too. There are four directions, and it's convenient to combine them.

A payment plan for the weak months

Low-season payments are known in advance: rent, payroll, subscriptions, loans. They get entered into a payment calendar several months ahead, and you can see on which days the balance drops below zero. Then the reserve has a specific amount and a specific date.

A reserve from the strong months

The shortfall amount gets set aside in installments from the high-revenue months. In the example, we split $9,000 across four months from May to August: $9,000 ÷ 4 = $2,250 a month. It's convenient to keep the reserve in a separate account so it doesn't get mixed in with day-to-day operations.

Flexible costs

Part of your fixed costs can be made variable: tie part of the team's pay to revenue, cut working hours in weak months, bring in seasonal workers only for the peak. Every such change reduces the shortfall, and the reserve along with it. Changes to pay and employee schedules should be checked against your country's labor law.

Demand in the weak months

Weak months can be filled: sell memberships or gift certificates during the high season that get used in the low season, make separate offers for the off-season, add services that depend less on the season. A prepayment isn't yet earnings: the service still has to be delivered, so money from memberships doesn't count toward the reserve. This direction works slowly, with results visible the following year, so it's planned together with the reserve.

How to see seasonality in your books

The seasonality index needs a single series: revenue for each month. In BizFin, that series is in the “Profit and Loss” report. By default, the report opens for the last 12 months, and in the calendar you can choose a different period, for example last year. In the “Breakdown by Category” table, the “Total Income” row shows revenue for each month: the numbers for the index formula from the article come from there.

The seasonality index itself isn't shown in the report as a separate indicator: you calculate it with the article's formula from the numbers in the table. To compare against the previous year, the “Compare” button is convenient: under the “Income,” “Expenses,” and “Net Profit” cards, the change versus the previous equivalent period appears.

Careful. Income in the report is counted by the date it was received. A prepayment for a membership lands in the month of payment, when the service hasn't been delivered yet. If there are many prepayments, the index will show a picture of receipts that may differ from the picture of work done.

Plans for the weak months go into the “Scheduled Transactions” section. Rent, payroll, and subscriptions get added as templates with a “Monthly” schedule, expected receipts as receipt templates. In “Calendar” mode, you flip through the months and see a balance forecast for each day, calculated from today's actual balance. A day is green if no account goes negative, and red if one might.

The calendar shows only what you've planned yourself, so expected receipts based on the seasonality index get entered manually. There's no revenue forecast for upcoming months and no plan-versus-actual comparison in the reports. Templates don't run automatically: a transaction appears in your books after you confirm it.

Advice. It's convenient to update the index once a year, when the season has finished: add the new year to the series and average the same months. After two or three years, the seasonality picture becomes more reliable.

What's worth remembering

• Seasonality repeats. A dip that returns in the same months several years in a row points to a season.

• The seasonality index compares months. A month's revenue divided by the average monthly revenue gives a number that's easy to compare.

• The break-even point divides the months. Everything below it needs a cushion, everything above it produces a surplus.

• The reserve equals the sum of shortfalls. It's set aside in installments from the strong months, with a cushion for deviations added to the calculated amount.

• The year gets evened out in several ways. A reserve, a payment plan, flexible costs, and demand in the weak months work together.

Frequently asked questions

What is business seasonality?

It's a rise and fall in revenue that repeats year after year in the same months. The cause can be weather, holidays, the school year, or vacations. Repetition is what separates a season from a one-off fluctuation.

How do you calculate the seasonality index?

Divide the month's revenue by the average monthly revenue for the year and multiply by 100%. For January with revenue of $18,000 against an average of $30,000, the index equals 60%.

How many years of data do you need for the index?

At least twelve months, ideally two or three years with the same months averaged. One year gives an approximate result, since one-off events could have occurred in it.

How do you calculate a reserve for the low season?

Calculate each month's result, add up the shortfalls of the months below the break-even point, and spread the amount across the strong months. In the example, that's $9,000, set aside at $2,250 over four months.

What if revenue in the weak months is below the break-even point?

Cover the shortfall with the reserve, then shrink it: turn part of your fixed costs into variable ones and fill the weak months with demand through memberships and separate off-season offers.

Can you see seasonality in BizFin?

Yes, revenue by month is visible in the “Profit and Loss” report, in the “Breakdown by Category” table. The seasonality index itself isn't shown in the report as a separate indicator: you calculate it with the article's formula.