One of the most common paid advertising mistakes is treating an ad budget as one big pool, instead of splitting it deliberately between reaching new people and bringing back people who already showed interest. Here's a practical framework for getting that split right.
Why the split matters
Prospecting campaigns show your ads to people who've never interacted with your brand — they're expensive to convert but essential for growth. Retargeting campaigns show ads to people who've already visited your site, engaged with your content, or added something to a cart — they convert at a much higher rate, but only work if there's already traffic to retarget. Run only prospecting, and you burn budget on cold audiences with no safety net. Run only retargeting, and you'll eventually run out of people to retarget.
A starting split for most accounts
For an account with no existing retargeting audience, starting around 70% prospecting and 30% retargeting is a reasonable baseline — you need volume before retargeting has anything to work with. As your retargeting audience grows (people who've visited your site, watched a video, or engaged on Instagram), that ratio typically shifts toward 50/50 or even 40% prospecting / 60% retargeting for accounts with strong existing traffic.
Set aside a testing budget too
Beyond the prospecting/retargeting split, Loop Digital Pro recommends reserving 10-15% of total spend specifically for testing new creative and audiences. Without a dedicated testing budget, accounts tend to run the same ad for months, and performance quietly declines as the audience becomes fatigued.
Track this in Ads Manager, not guesswork
Meta's own Business Help Center has detailed guidance on setting up separate campaigns for prospecting and retargeting audiences, along with the tracking setup needed to measure each accurately. Getting the pixel and conversion tracking right matters more than the exact percentage split — without accurate data, any budget split is just a guess.
When to adjust the split
Watch cost-per-result by campaign type weekly, not monthly. If retargeting cost-per-result is climbing because the audience is small and fatigued, that's a signal to shift more budget back to prospecting to refresh the pool of people to retarget later.
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