Dropped my Meta bid cap 30% to cut CPA. Impressions fell by half instead

YUNJI Agency

Registered Member

Jul 10, 2026

50

9

• Monday at 8:32 AM

• #1

Had this happen earlier this week.

I dropped the manual bid cap about 30% below Meta's suggested range because I wanted to bring costs down. The same day, impressions fell by more than half and spend almost stopped. CPA looked fine on paper, but only because there was barely any volume.

At first I blamed the audience. Checked the audience size and it hadn't changed. Looked at the time-of-day breakdown too, nothing unusual there. The change log made it pretty clear: the drop started right after the new cap went live. We were simply losing most auctions before delivery could get going.

I moved the cap back closer to the suggested range. Impressions and spend recovered the next day. CPA ended up slightly above the original target, but at least the campaign was producing volume again.

On this account, testing around 10% below the suggested range still delivered. Going much lower killed volume quickly, so I'm treating that as an account-specific starting point rather than a universal rule.

How far below Meta's suggested bid have you gone before delivery starts falling apart?

 

Good_Agency_Ads

Elite Member

Jr. VIP

Dec 21, 2023

1,750

844

• Monday at 10:58 AM

• #2

I’d recommend adjusting it by 5–10% at a time and monitoring the performance for around 24 hours before making another change.

 

YUNJI Agency

Registered Member

Jul 10, 2026

50

9

• Monday at 12:23 PM
• Thread Starter Thread Starter

• #3

Good_Agency_Ads said:

I’d recommend adjusting it by 5–10% at a time and monitoring the performance for around 24 hours before making another change.

Click to expand...

Yeah, that’s probably the safer way. I moved it too far in one shot here. Next time I’ll test smaller changes and give each one a full day before touching it again.

 

LOQ Marketing Agency

Regular Member

Jr. VIP

Oct 7, 2025

396

70

• Tuesday at 4:48 PM

• #4

If you make a big change, it will have a serious impact. Change gradually, step by step; it will be more effective. Normally, you should stick to the bids provided, as that's the most effective level. If you adjust, don't make too many changes, as it will significantly reduce the number compared to the suggested quantity.

 

jibamu

Newbie

Aug 25, 2023

20

10

• Tuesday at 5:02 PM

• #5

I’ve seen the same thing with bid caps. I treat Meta’s suggested range more like a reference point than a hard rule then test downward gradually. Around 10% below can often be fine.

 

S

SwissExplorer

Newbie

Jul 14, 2026

32

13

• Yesterday at 12:07 AM

• #6

Yes i've seen this too as 10% below Meta’s suggested bid can still work but if you go too low then the impressions and spend can drop fast because it really depends on the account.