You’ve just been given your PPC advertising budget for the next year, and you’re trying to calculate your monthly PPC budgets. While you could easily divide your budget by 12 and leave it at that, you should be calculating your budgets more precisely to account for seasonality. Although a simple concept, accounting for seasonality when projecting budgets is one that doesn’t get applied enough as it should.

Since you’ll usually see stronger performance during certain parts of the year and weaker performance during others, it makes sense to spend more money during those better performing times of year. For example, if you usually see a $50 CPA in October and November and a $75 CPA during the summer months, you’d want to invest more advertising budget during those fall months. A cheaper CPA coupled with larger budgets means more conversions, and more conversions leads to a more successful business.

There are many ways to derive the ideal PPC budget allocation, but here is a simple yet sophisticated 20-minute method to help you allocate budgets.

Directions for Calculating Your PPC Seasonality

Before you start, you’ll want to make sure you have at least two years of historical data for clicks and conversions. The more data you have, the better. This is to make sure you aren’t basing calculations off any outliers or random variances.

1. Once you figure out how far back you can go, pull click and conversion data segmented by month.

2. Open the Excel file and create a new month column with the =MONTH formula for each row. Once you have this, copy this entire column, special paste as values, and name this new column as Month2. This makes it easy to pivot all of your data later on.

Excel document with spend calculated by month

3. Next, select all of your data (Month2, Clicks, and Conversions) and make a pivot table from this. Use Month2 as the “Rows” for your new table, and the sum of clicks and sum of conversions as your “Values.”

excel field list

4. Calculate each month’s conversion rate by dividing the conversions in this new table by the clicks. This will give you a good sense of how each month performs on average. Also calculate the overall conversion rate, as this will give you a benchmark for measuring the months.

conversion rate calculator

5. Now, calculate each conversion rate’s percent difference from the overall conversion rate. This shows how each month performed relative to the overall account average.

calculating difference of monthly conversion rate vs. average

6. Take your budget for the year and divide it by 12. Then, multiply each month’s budget with 1 plus its respective conversion percent difference. Here you’ll arrive at your ideal spend allocations, with budgets based off of how each month performs in terms of conversion rate.

calculating monthly budget

Accounting for seasonality is something you should make sure to consider while planning your PPC budgets. It’s a simple process that takes less than 30 minutes and ensures you’re maximizing conversions during strong months of the year and saving money during less profitable months.