# How to get an alert when CTR drops

> Set an alert when CTR falls: compare the last 7 days with the 7 before, alert on a 25% drop, and brief new creative when it fires. With a worked example.
- **Author**: Marxx
- **Published**: 2026-11-07
- **Category**: Alerts
- **URL**: https://marxx.ai/library-guides/how-to-get-an-alert-when-ctr-drops

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Set a CTR drop alert that compares each ad's click-through rate over the last 7 days with the 7 days before, and fires when it falls by 25% or more. Add a minimum of a few thousand impressions so small ads do not trigger it.

## Why watch CTR

[CTR](/glossary/ctr), or click-through rate, is the share of people who saw your ad and clicked. It often falls before cost per result rises, because people stop reacting to an ad before the cost catches up. A CTR alert gives you a few days to replace the ad while it still pays its way.

## The formula

CTR change = (CTR last 7 days − CTR previous 7 days) / CTR previous 7 days

Compare each ad with its own past, not with the account average. A carousel and a reel never have the same CTR, so one fixed number would fire on the wrong ads.

## A worked example

Say Monsoon reel 02 is a Reels ad for a travel brand.

1. **Previous 7 days:** 48,000 impressions, 768 clicks. CTR = 768 / 48,000 = 1.6%.
2. **Last 7 days:** 52,000 impressions, 572 clicks. CTR = 572 / 52,000 = 1.1%.
3. **Change:** (1.1 − 1.6) / 1.6 = −0.31, so CTR is down 31%.
4. **Check the rule:** 31% is more than the 25% limit, and 52,000 impressions is above the 5,000 minimum. The alert fires.

Another ad going from 2.0% to 1.7% is down 15%. It stays quiet. That is a normal weekly swing.

## Settings that work

| Setting | Starting value | Why |
|---|---|---|
| Level | Ad | Each creative tires on its own |
| Window | Last 7 days vs previous 7 | Smooths out weekday swings |
| Drop to alert | 25% | Below that is often noise |
| Minimum | 5,000 impressions | Small samples swing wildly |
| Severity | Medium | It needs action this week, not this hour |
| Check | Mondays | Fits a weekly creative review |

## When the alert fires

1. **Look at frequency.** If [frequency](/glossary/frequency) rose at the same time, the same people are seeing the ad too often. That is ad fatigue.
2. **Look at the first seconds.** If [hook rate](/glossary/hook-rate) fell too, the opening has stopped stopping the scroll.
3. **Brief a new version.** Keep the angle that worked and change the hook, the first frame or the format. One brief, two or three new ads.
4. **Do not raise the budget to compensate.** More spend on a tiring ad usually makes it tire faster.

Our guide on [improving CTR on Facebook ads](/guides/how-to-improve-ctr-on-facebook-ads) covers the creative fixes.

We make Marxx. A Marxx CTR falling alert reads "CTR down 31% (last 7 days)" with the ad's name and severity, in the client's Slack channel. Setup is in [Meta ads alerts in Slack](/guides/how-to-set-up-meta-ads-alerts-in-slack).

## FAQ

### Should I use link CTR or all CTR?

Use link CTR for ads that send people to a site or form. All CTR counts likes and profile taps too, which can hide a real drop.

### Why compare 7 days and not yesterday?

Daily CTR jumps around with the day of the week and the audience Meta picks. Seven days gives a steadier number.

### Can CTR drop while results stay fine?

Yes. Treat the alert as an early warning and check cost per result before you pause anything.

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