Here are some incredibly useful custom columns that I add to every Google Ads account I manage:
Column Name | Formula | Type |
---|---|---|
ROAS | Conv. Value ÷ Cost | % |
Cost of Sales (COS) | Cost ÷ Conv. Value | % |
% COS CPC | Conv. Value ÷ Clicks x % | $ |
Optimistic % COS CPC | (Conv. Value + (Conv. Value ÷ Conversions)) ÷ Clicks x % | $ |
Below is each column described in more detail:
ROAS
ROAS stands for Return On Ad Spend
Name | ROAS |
Description | Return on Ad Spend |
Formula | Conv. Value ÷ Cost |
Data Format | Percent (%) |

This metric tells you the percentage of revenue generated for each dollar in ad spend.
100% ROAS means that there is a 1:1 relationship between your revenue and ad spend. For every $1 spent, you generated $1 in revenue.
200% ROAS means that is a 2:1 relationship between your revenue and ad spend. For every $1 spent, you generated $2 in revenue.
Many of the automated bidding strategies in Google Ads let you specify a target ROAS goal (Return on Ad Spend), so adding this custom column allows you quickly see in a glance if your campaigns, ad groups, and keywords are meeting your ROAS targets.
COS (Cost of Sales)
COS stands for Cost Of Sales
Name | COS |
Description | Cost of Sales |
Formula | Cost ÷ Conv. Value |
Data Format | Percent (%) |

This metric is the inverse of ROAS. It tells us what percentage of revenue was spent on ads.
This metric is usually more aligned with how most businesses look at Ad Spend (as a cost). I find looking at things from a Cost of Sales standpoint makes more sense than ROAS for most businesses. (ROAS is more aligned with how ad agencies think about ad spend).
20% Cost of Sales means that for every $1 in revenue, we spent $0.20 on ads.
If you know your profit margins, then it’s easy to see when your Cost of Sales exceeds those margins, and when you start to lose money on every sale.
To convert between ROAS and COS use these formulas:
Cost of Sales (COS) = 1 / ROAS
Return on Ad Spend (ROAS) = 1 / COS
% COS CPC
“What is the max Cost per Click bid that will keep me below the specified % Cost of Sales target.“
Name | 5% COS CPC |
Description | Maximum CPC to stay below 5% Cost of Sales |
Formula | Conv. Value ÷ Clicks x 0.05 |
Data Format | Money ($) |

If you use Manual CPC bidding for a campaign, creating a few of these columns for various profit margins will give you access to quick calculation for what your max CPC bids.
I usually create a few of these columns. Eg:
5% COS | Max CPC bid to hit 5% cost of sales |
35% COS | Max CPC bid to hit 35% cost of sales |
55% COS | Max CPC bid to hit 55% cost of sales |
The number of columns you create and the values you use will depends on your business and profit margins. I usually create one column that targets a very low cost of sales (eg: 5%, that is used for Branded search bids), and then another column that targets my maximum profit margin (eg: 55%, that is used for Unbranded/Prospecting search bids).
Optimistic % COS CPC
“What is the max Cost per Click bid that will keep me below the specified % Cost of Sales target, under the assumption that the next click will result in a sale“
Name | Optimistic 5% COS CPC |
Description | Maximum CPC to stay below 5% Cost of Sales, assuming the next click will result in a sale |
Formula | (Conv. Value + (Conv. Value ÷ Conversions)) ÷ Clicks x 0.05 or use a harde-coded order value: (Conv. Value + avg_order_value) ÷ Clicks x 0.05 |
Data Format | Money ($) |

This custom column is similar to the % COS CPC column above, except that it is optimistic in assuming that the “next click” will result in a sale, and includes the next sale’s revenue in the Max cost per click calculations.
You can either hard-code your average conversion value, or you can calculate it based on past conversion data.
This column is useful when you are starting a new campaign where you don’t have much conversion data yet, and you want to be optimistic with your bidding.