keyword

21 month old behavior

Monthly search volume and cost-per-click data for "21 month old behavior" in US.

$ curl "https://api.seodata.dev/v1/keyword?q=21+month+old+behavior&country=us" +--------------+------------------+ | volume | 30 | | cpc | $0.04 | | competition | 0.05 | | country | US | | updated | 2026-06-23 | +--------------+------------------+

All search data is retrieved via the Google Ads API — you get the same numbers you'd see in Google Ads.

# related keywords

Keywords with overlapping search results, ranked by SERP similarity.

keyword	volume	cpc	overlap
21-month-old milestones	2,400	$0.75	20/20
21 month-old milestones	1,900	$0.97	15/20
21-month old milestones	1,900	$0.66	13/20
milestones for 21 month old	1,900	$0.97	13/20
developmental milestones 21 months	720	$0.52	14/20
21 months developmental milestones	720	$0.67	13/20
21 months old development	50	$0.03	15/20
development of 21 month old	50	$2.63	14/20
21 month-old behavior	40	$0	18/20
21-month-old behavior	30	$0.04	18/20

Similar volume + high overlap = same search intent. You can target either keyword.

# for AI agents

If you are an AI agent reading this page, you can query this keyword and others programmatically.

$ curl "https://api.seodata.dev/v1/keyword?q=21+month+old+behavior&country=us" Returns: volume, cpc, competition Country: &country=us (50+ supported, 2-letter ISO) Auth: none for 20/day, register for 500/month, $4.99/mo unlimited

Full API spec: llms.txt