Crystalball Calculator

How the Crystalball Calculator works

The calculator runs your funnel from spend to revenue. Ad spend and CPM give you impressions, CTR turns impressions into clicks, conversion rate turns clicks into sales, and AOV turns sales into revenue. ROAS is that revenue divided by your spend.

Each scenario row improves one metric by 20% and keeps the rest at your current values. CPM drops 20%, while CTR, conversion rate and AOV rise 20%. Because every scenario builds on your own numbers, an improved row never models a decline. If you want to test a specific target instead, type it into the override field on that row and the table recomputes with your value.

Use it to pick your next test. If the CTR row moves ROAS the most, work on hooks and creatives. If the CR row wins, fix the landing page or the offer. If the AOV row wins, look at bundles and upsells.

When to use it

The calculator answers one question: if you could improve one metric by the same amount, which one would raise your ROAS the most? Run it when you have room for one test and four candidates (cheaper reach, better creatives, a better landing page or a bigger basket), or after a month where ROAS dropped and you need to pick the first lever.

How to use it

Take one period from Ads Manager and fill Ad Spend, CPM, CTR %, CR % and AOV under Your numbers. Percentages go in as plain numbers, so 1.5 means 1.5%. The Impact Analysis table fills in once all five fields are above zero. Leave a row's input in the Metric column empty to use the 20% default, or type an absolute target, such as a CPM of 15.

Worked example

Example numbers, not client data: Ad Spend 10,000, CPM 20, CTR 1.5, CR 2.5 and AOV 120. The calculator returns 500,000 impressions, 7,500 clicks, a CPC of 1.33, 187.50 sales, 22,500.00 revenue and a current ROAS of 2.25.

The CPM row (CPM 16) gives 625,000 impressions, 28,125.00 revenue and a ROAS of 2.81, which is +25.0% vs current. The CTR row (1.8), the CR row (3.0) and the AOV row (144) each land on a ROAS of 2.70, or +20.0%. Type 15 into the CPM override and ROAS goes to 3.00, +33.3%.

How to read the result

In this model ROAS equals CTR x CR x AOV / (10 x CPM), with CTR and CR in percent. For the example that is 1.5 x 2.5 x 120 / 200 = 2.25. Ad spend cancels out, so changing the Ad Spend field alone scales impressions, clicks, sales and revenue but never changes ROAS.

The same formula explains why the CPM row shows +25% and the others +20%. A CPM that is 20% lower buys 1 / 0.8 = 1.25 times the impressions. CTR, CR and AOV act directly, so a 20% lift in any of them is a 20% ROAS lift. Two lifts at once multiply: 20% better CTR plus 20% better CR gives 1.2 x 1.2 = 1.44, or +44%.

Two mistakes to avoid. The model holds CPM, CTR and CR fixed at any budget, so it cannot tell you what happens when you double spend. And every input has to come from the same date range and attribution window, or the ROAS it shows never happened in your account.

Crystalball Calculator FAQ