First off, there’s no way to know for certain which of these onsite variables Google actually considers ranking factors. There’s also no way to know how to prioritize these (potential) ranking factors.

What I do know is that you can measure these variables in the SERPs to see which ones have strong correlations for positive and negative rankings in Google—and the results vary wildly from keyword to keyword.

That said, here are the current 549 onsite ranking factors that I measure to produce my Customized Onsite SEO Checklists. I’ll add more details on each variable as time permits. If you have any questions post them in the comments and I’ll answer them as soon as instantly as I can!

H Tag Ranking Factors

  1. Keywords in H1 and H2 Tags
  2. Keywords in H1 Tags
  3. Keywords in H1, H2, and H3 Tags
  4. Keywords in H1-H6 Tags
  5. Keywords in H2 Tags
  6. Keywords in H3 Tags
  7. Keywords in H4 Tags
  8. Keywords in H4-H6 Tags
  9. Keywords in H5 Tags
  10. Keywords in H6 Tags
  11. Keywords making whole H1 Tags
  12. Keywords making whole H1, H2, and H3 Tags
  13. Keywords making whole H1-H6 Tags
  14. Keywords making whole H2 Tags
  15. Keywords making whole H3 Tags
  16. Keywords making whole H4 Tags
  17. Keywords making whole H4-H6 Tags
  18. Keywords making whole H5 Tags
  19. Keywords making whole H6 Tags
  20. Leading Keywords in H1 Tags
  21. Leading Keywords in H1, H2, and H3 Tags
  22. Leading Keywords in H1-H6 Tags
  23. Leading Keywords in H2 Tags
  24. Leading Keywords in H3 Tags
  25. Leading Keywords in H4 Tags
  26. Leading Keywords in H4-H6 Tags
  27. Leading Keywords in H5 Tags
  28. Leading Keywords in H6 Tags
  29. Search Terms in H1 Tags
  30. Search Terms in H1-H6 Tags
  31. Search Terms making whole H1 Tags
  32. Search Terms making whole H1, H2, and H3 Tags
  33. Search Terms making whole H1-H6 Tags
  34. Search Terms making whole H2 Tags
  35. Search Terms making whole H3 Tags
  36. Search Terms making whole H4 Tags
  37. Search Terms making whole H4-H6 Tags
  38. Search Terms making whole H5 Tags
  39. Search Terms making whole H6 Tags

Ahrefs Ranking Factors (Yeah, yeah… Lots of these are Offsite)

  1. Ahrefs Alternate Backlinks
  2. Ahrefs Backlinks
  3. Ahrefs Canonical Backlinks
  4. Ahrefs Dofollow Backlinks
  5. Ahrefs Domain Rating
  6. Ahrefs Edu Backlinks
  7. Ahrefs External Links
  8. Ahrefs Facebook Clicks
  9. Ahrefs Facebook Comments Box
  10. Ahrefs Facebook Comments
  11. Ahrefs Facebook Interactions
  12. Ahrefs Facebook Likes
  13. Ahrefs Facebook Shares
  14. Ahrefs Gov Backlinks
  15. Ahrefs Has Alternate Backlinks
  16. Ahrefs Has Backlinks
  17. Ahrefs Has Canonical Backlinks
  18. Ahrefs Has DoFollow Backlinks
  19. Ahrefs Has Domain Rating
  20. Ahrefs Has EDU Backlinks
  21. Ahrefs Has External Links
  22. Ahrefs Has Facebook Clicks
  23. Ahrefs Has Facebook Comments Box
  24. Ahrefs Has Facebook Comments
  25. Ahrefs Has Facebook Interactions
  26. Ahrefs Has Facebook Likes
  27. Ahrefs Has Facebook Shares
  28. Ahrefs Has Google Plus Ones
  29. Ahrefs Has Gov Backlinks
  30. Ahrefs Has Html Pages
  31. Ahrefs Has Image Backlinks
  32. Ahrefs Has Images
  33. Ahrefs Has Internal Links
  34. Ahrefs Has Linked Root Domains
  35. Ahrefs Has LinkedIn Shares
  36. Ahrefs Has Median Shares
  37. Ahrefs Has NoFollow Backlinks
  38. Ahrefs Has Not Sitewide Backlinks
  39. Ahrefs Has Pinterest Shares
  40. Ahrefs Has Redirects
  41. Ahrefs Has RSS Backlinks
  42. Ahrefs Has Shares
  43. Ahrefs Has Sitewide Backlinks
  44. Ahrefs Has Text Backlinks
  45. Ahrefs Has Twitter Shares
  46. Ahrefs HTML pages
  47. Ahrefs Image Backlinks
  48. Ahrefs Images
  49. Ahrefs Internal Links
  50. Ahrefs Linked Root Domains
  51. Ahrefs LinkedIn Shares
  52. Ahrefs Median Shares
  53. Ahrefs NoFollow Backlinks
  54. Ahrefs Not Sitewide Backlinks
  55. Ahrefs Page Size
  56. Ahrefs Pages
  57. Ahrefs Pinterest Shares
  58. Ahrefs Plus Ones
  59. Ahrefs Rank
  60. Ahrefs Redirects
  61. Ahrefs Referring Class C Addresses
  62. Ahrefs Referring Domains
  63. Ahrefs Referring IP Addresses
  64. Ahrefs Referring Pages
  65. Ahrefs RSS Backlinks
  66. Ahrefs Sitewide Backlinks
  67. Ahrefs Text Backlinks
  68. Ahrefs Total Shares
  69. Ahrefs Twitter Shares
  70. Ahrefs Word Count

Meta Tag Ranking Factors

  1. Has Meta Author
  2. Has Meta Charset
  3. Has Meta Description
  4. Has Meta Keywords
  5. Has Meta Robots
  6. Has Meta Twitter Account ID
  7. Has Meta Twitter Cards
  8. Has Meta Twitter Description
  9. Has Meta Twitter Domain
  10. Has Meta Twitter Site
  11. Has Meta Twitter Title
  12. Has Meta Viewport
  13. Keywords in Meta Descriptions
  14. Keywords in Meta Keywords
  15. Keywords in Meta OpenGraph Description
  16. Keywords in Meta OpenGraph Site Name
  17. Keywords in Meta OpenGraph Title
  18. Keywords in Meta Twitter Description
  19. Keywords in Meta Twitter Domain
  20. Keywords in Meta Twitter Title
  21. Meta Description Length
  22. Number of Meta Generator Tags
  23. Number of Meta Keywords
  24. Search Terms in Meta Descriptions

MicroData Ranking Factors

  1. Has MicroData Address Locality
  2. Has MicroData Address Region
  3. Has MicroData Address
  4. Has MicroData Aggregate Rating
  5. Has MicroData Answer Count
  6. Has MicroData Article Body
  7. Has MicroData Author
  8. Has MicroData Availability
  9. Has MicroData Content URL
  10. Has MicroData Date Published
  11. Has MicroData Description
  12. Has MicroData Email
  13. Has MicroData Encoding Format
  14. Has MicroData Exif Data
  15. Has MicroData Headline
  16. Has MicroData Image
  17. Has MicroData Interaction Count
  18. Has MicroData Interaction Service
  19. Has MicroData Interaction Statistic
  20. Has MicroData Interaction Type
  21. Has MicroData ISBN
  22. Has MicroData Item List Element
  23. Has MicroData Location
  24. Has MicroData name
  25. Has MicroData Number of Pages
  26. Has MicroData Offer Count
  27. Has MicroData Offers
  28. Has MicroData Opening Hours
  29. Has MicroData Postal Code
  30. Has MicroData Potential Action
  31. Has MicroData Price Range
  32. Has MicroData Price
  33. Has MicroData Product ID
  34. Has MicroData Publisher
  35. Has MicroData Query Input
  36. Has MicroData Rating Value
  37. Has MicroData Review Count
  38. Has MicroData Review Rating
  39. Has MicroData Review
  40. Has MicroData Street Address
  41. Has MicroData Suggested Answer
  42. Has MicroData Target
  43. Has MicroData Telephone
  44. Has MicroData Text
  45. Has MicroData Thumbnail
  46. Has MicroData Up Vote Count
  47. Has MicroData URL
  48. Has MicroData Video
  49. Has MicroData

SEMRush Ranking Factors

  1. SEMRush Advertiser Ad Places
  2. SEMRush Advertiser Ads
  3. SEMRush Advertiser First Seen
  4. SEMRush Advertiser Last Seen
  5. SEMRush Advertiser Media Ads
  6. SEMRush Advertiser Text Ads
  7. SEMRush Advertiser Times Seen
  8. SEMRush Adwords Cost
  9. SEMRush Adwords Keywords
  10. SEMRush Adwords Traffic
  11. SEMRush Backlinks Score
  12. SEMRush Backlinks
  13. SEMRush DoFollow Backlinks
  14. SEMRush International Backlinks
  15. SEMRush International Domains
  16. SEMRush Media Ads
  17. SEMRush NoFollow Backlinks
  18. SEMRush Organic Cost
  19. SEMRush Organic Keywords
  20. SEMRush Organic Traffic
  21. SEMRush Product Listing Ad Keywords
  22. SEMRush Product Listing Ad Uniques
  23. SEMRush Publisher Ad Places
  24. SEMRush Publisher Ads
  25. SEMRush Publisher First Seen
  26. SEMRush Publisher Last Seen
  27. SEMRush Publisher Text Ads
  28. SEMRush Publisher Times Seen
  29. SEMRush Rank
  30. SEMRush Referring Domains
  31. SEMRush Referring IP Addresses
  32. SEMRush Trust Score
  33. SEMRush US Backlinks
  34. SEMRush US Domains

Title Ranking Factors

  1. Google Result Has Rewritten Page Title
  2. Google Result Has Unmodified Page Title
  3. Has Domain In Title
  4. Has Domain Phrase In Title
  5. Has MicroFormat Entry Title
  6. Keywords in Title Attributes
  7. Keywords in Title Tag
  8. Keywords making whole Title Tag
  9. Leading Keywords in Title Tag
  10. Search Terms in the Title Tag
  11. Search Terms making whole Title Tag
  12. Title Has Question Words
  13. Title Has Sales Words
  14. Title Length
  15. Word Count in Title Tag

Search Term Ranking Factors

  1. Search Terms in Body Tag
  2. Google Result URL Exact Search Term Matches
  3. Search Terms in A Tags
  4. Google Result Link Text Exact Search Term Matches
  5. Search Terms in the HTML Tag
  6. Search Terms in Sentences
  7. Search Terms making whole A Tags
  8. Exact Search Term Keyword Density
  9. Google Result Summary Exact Search Term Matches

Google Result Ranking Factors

  1. Google Result Display URL Matches
  2. Google Result Document Matches
  3. Google Result Domain Has Hyphen
  4. Google Result Domain Has Leading Matches
  5. Google Result Domain Has Numbers
  6. Google Result Domain Length
  7. Google Result Domain Matches
  8. Google Result Has Domain In Link Text
  9. Google Result Has Domain Phrase In Link Text
  10. Google Result Has Dot Com Net Org
  11. Google Result Has Dot Com
  12. Google Result Has Exact Match Domain
  13. Google Result Has File Extension
  14. Google Result Has Params
  15. Google Result Has Price
  16. Google Result Has Rating
  17. Google Result Has Schema
  18. Google Result Has Subdomain
  19. Google Result Host Has Numbers
  20. Google Result Host Leading Matches
  21. Google Result Host Length
  22. Google Result Host Matches
  23. Google Result Link Text Has Ellipsis
  24. Google Result Link Text Has Year
  25. Google Result Link Text Length
  26. Google Result Link Text Matches
  27. Google Result Not Dot Com Net Org
  28. Google Result Number of Dirs in Path
  29. Google Result Number of Site Links
  30. Google Result Param Matches
  31. Google Result Path Matches
  32. Google Result Publish Date
  33. Google Result Subdomain Matches
  34. Google Result Summary Has Ellipsis
  35. Google Result Summary Has Year
  36. Google Result Summary Length
  37. Google Result Summary Text Matches
  38. Google Result URL has Year
  39. Google Result URL Length
  40. Google Result URL Matches
  41. Google Result Uses HTTPS

DomDetailer Ranking Factors

  1. DomDetailer Facebook Comments
  2. DomDetailer Facebook Shares
  3. DomDetailer Google Plus Ones
  4. DomDetailer Linkedin
  5. DomDetailer Majestic CF
  6. DomDetailer Majestic IPs
  7. DomDetailer Majestic Links
  8. DomDetailer Majestic Referring .edu Links
  9. DomDetailer Majestic Referring .gov Links
  10. DomDetailer Majestic Referring Domains
  11. DomDetailer Majestic Referring Subnets
  12. DomDetailer Majestic TF
  13. DomDetailer Moz DA
  14. DomDetailer Moz Links
  15. DomDetailer Moz PA
  16. DomDetailer Moz Rank
  17. DomDetailer Moz Spam
  18. DomDetailer Moz Trust
  19. DomDetailer Pinterest Pins

Affiliate Ranking Factors

  1. Has Affiliate Links – AdCell
  2. Has Affiliate Links – Affilinet
  3. Has Affiliate Links – Amazon
  4. Has Affiliate Links – Belboon
  5. Has Affiliate Links – ClickBank
  6. Has Affiliate Links – Commission Junction
  7. Has Affiliate Links – Digistore24
  8. Has Affiliate Links – Ebay
  9. Has Affiliate Links – QuinStreet
  10. Has Affiliate Links – Rakuten
  11. Has Affiliate Links – Walmart
  12. Has Affiliate Links – Zanox
  13. Has Affiliate Links
  14. Number of Affiliate Links – AdCell
  15. Number of Affiliate Links – Affilinet
  16. Number of Affiliate Links – Amazon
  17. Number of Affiliate Links – Belboon
  18. Number of Affiliate Links – ClickBank
  19. Number of Affiliate Links – Commission Junction
  20. Number of Affiliate Links – Digistore24
  21. Number of Affiliate Links – Ebay
  22. Number of Affiliate Links – QuinStreet
  23. Number of Affiliate Links – Rakuten
  24. Number of Affiliate Links – Walmart
  25. Number of Affiliate Links – Zanox

MicroFormat Ranking Factors

  1. Has MicroFormat Author
  2. Has MicroFormat DT-Published
  3. Has MicroFormat E-Content
  4. Has MicroFormat E-Description
  5. Has MicroFormat Entry Content
  6. Has MicroFormat H-Card
  7. Has MicroFormat HEntry
  8. Has MicroFormat H-Product
  9. Has MicroFormat H-Review
  10. Has MicroFormat P-Author
  11. Has MicroFormat P-Brand
  12. Has MicroFormat P-Category
  13. Has MicroFormat P-Name
  14. Has MicroFormat P-Price
  15. Has MicroFormat P-Rating
  16. Has MicroFormat P-Review
  17. Has MicroFormat P-Summary
  18. Has MicroFormat Published
  19. Has MicroFormat U-Email
  20. Has MicroFormat U-Identifier
  21. Has MicroFormat U-Photo
  22. Has MicroFormat U-URL
  23. Has MicroFormats

Link-Related Ranking Variables

  1. Has Amp Link Tag
  2. Has Rel Next Link
  3. Has Rel Prev Link
  4. Has RSS Link
  5. Number of DoFollow External Links
  6. Number of DoFollow Links
  7. Number of External Links
  8. Number of Facebook Share Links
  9. Number of Google Plus Share Links
  10. Number of HTTPS Links
  11. Number of Internal Links
  12. Number of Linked In Accounts
  13. Number of LinkedIn Pages
  14. Number of Links
  15. Number of MailTo Links
  16. Number of NoFollow Externa Links
  17. Number of NoFollow Links
  18. Number of Rel Author Links
  19. Number of Social Share Links
  20. Number of Twitter Share Links
  21. Percentage of DoFollow External Links
  22. Percentage of DoFollow Internal Links
  23. Percentage of DoFollow Links
  24. Percentage of NoFollow External Links
  25. Percentage of NoFollow Internal Links
  26. Percentage of NoFollow Links

Schema Ranking Factors

  1. Has Schema Aggregate Rating
  2. Has Schema Answer
  3. Has Schema Article
  4. Has Schema Audio Object
  5. Has Schema Blog Posting
  6. Has Schema Corporation
  7. Has Schema Event
  8. Has Schema Image Object
  9. Has Schema Interaction Counter
  10. Has Schema Item List
  11. Has Schema Local Business
  12. Has Schema Markup
  13. Has Schema Offer
  14. Has Schema Organization
  15. Has Schema Person
  16. Has Schema Place
  17. Has Schema Product
  18. Has Schema Question
  19. Has Schema Rating
  20. Has Schema Review
  21. Has Schema Search Action
  22. Has Schema Service
  23. Has Schema Store
  24. Has Schema Video Object
  25. Has Schema Web Page
  26. Has Schema Website

Keyword Ranking Factors

  1. Keywords in A Tag HREFs
  2. Keywords in A Tags
  3. Keywords in Absolute URLs
  4. Keywords in Alt Attributes
  5. Keywords in Article Tags
  6. Keywords in B Tags
  7. Keywords in Blockquote Tags
  8. Keywords in Body Tag
  9. Keywords in Cite Tags
  10. Keywords in Class Attributes
  11. Keywords in Em Tags
  12. Keywords in Host Citations
  13. Keywords in HTML Comments
  14. Keywords in I Tags
  15. Keywords in ID Attributes
  16. Keywords in Label Tags
  17. Keywords in LI Tags
  18. Keywords in Name Attributes
  19. Keywords in NoScript Tags
  20. Keywords in Option Tags
  21. Keywords in P Tags
  22. Keywords in page’s most used phrase
  23. Keywords in page’s top 10 most used phrases
  24. Keywords in page’s top 3 most used phrases
  25. Keywords in page’s top 5 most used phrases
  26. Keywords in Pre Tags
  27. Keywords in Section Tags
  28. Keywords in Sentences
  29. Keywords in Span Tags
  30. Keywords in Strong Tags
  31. Keywords in the Canonical URL
  32. Keywords in the First 100 Words
  33. Keywords in the HTML Tag
  34. Keywords in the last 100 words
  35. Keywords in U Tags
  36. Keywords in Value Attributes
  37. Keywords making whole A Tags
  38. Keywords making whole B Tags
  39. Keywords making whole LI Tags
  40. Keywords making whole Option Tags
  41. Keywords making whole Span Tags
  42. Keywords making whole Strong Tags
  43. Keywords making whole U Tags

Number of X Ranking Factors

  1. Number of Absolute URLs
  2. Number of AdRoll Ads
  3. Number of Ads
  4. Number of Amazon Ads
  5. Number of Bytes to First Match
  6. Number of CSS Includes
  7. Number of Email Addresses
  8. Number of Facebook Accounts
  9. Number of FaceBook Pages
  10. Number of Flickr Images
  11. Number of Forms
  12. Number of Google Ads
  13. Number of Google Maps
  14. Number of Google Plus Accounts
  15. Number of Google Plus Pages
  16. Number of HREF Lang Tags
  17. Number of Images with Alt Text
  18. Number of Images without Alt Text
  19. Number of Images
  20. Number of Includes
  21. Number of Instagram Pages
  22. Number of JavaScript Includes
  23. Number of PingBacks
  24. Number of Redirects
  25. Number of Sentences
  26. Number of Social Accounts
  27. Number of Social Pages
  28. Number of Trademarks
  29. Number of Tumblr Pages
  30. Number of Twitter Accounts
  31. Number of US Phone Numbers
  32. Number of Videos
  33. Number of Vimeo Embeds
  34. Number of YouTube Accounts
  35. Number of YouTube Embeds

38 “Has X” Ranking Factors

  1. Has AdRoll Ads
  2. Has Ads
  3. Has Amazon Ads
  4. Has Apple Touch Icon
  5. Has Canonical URL
  6. Has Comment CTA
  7. Has Comments
  8. Has Contact Page
  9. Has Copyright
  10. Has Disqus
  11. Has Facebook Comments
  12. Has Facebook Page ID
  13. Has FavIcon
  14. Has Flickr
  15. Has Google Ads
  16. Has Google Analytics
  17. Has Google Maps
  18. Has Google Trusted Store
  19. Has Google Verify
  20. Has HREF Lang
  21. Has Intense Debate Comments
  22. Has LiveFyre Comments
  23. Has OpenGraph Image
  24. Has OpenGraph Type
  25. Has OpenGraph Video
  26. Has Pingbacks
  27. Has Privacy Policy
  28. Has RDFa
  29. Has Rel Pagination
  30. Has Terms of Service
  31. Has Trademarks
  32. Has US Phone Number
  33. Has Video
  34. Has Vimeo Embed
  35. Has WordPress Generator Tag
  36. Has XMLRPC
  37. Has YouTube Embed
  38. Is or Has AMP

13 “Is X” Ranking Factors

  1. Is AMP page
  2. Is Blogger Website
  3. Is Drupal Website
  4. Is Google Site
  5. Is Joomla Website
  6. Is OpenGraph Type Article
  7. Is Shopify Website
  8. Is SquareSpace Website
  9. Is Tumbler Website
  10. Is Weebly Website
  11. Is Wix Website
  12. Is WordPress Website
  13. Load Time Milliseconds

19 Miscellaneous Ranking Factors

  1. Average Words Per Sentence
  2. Bing Page Count
  3. Body Tag Size Kilobytes
  4. Clean Text Kilobytes
  5. Exact Match Term Frequency
  6. Exact Match TF/IDF
  7. Flesch Kincaid Reading Ease
  8. Flesch Kincaid Reading Grade
  9. Google Plus Ones
  10. Head Size Kilobytes
  11. I Tag Exact Matches
  12. Inline CSS Kilobytes
  13. Inline Javascript Kilobytes
  14. Match Density in Words
  15. Match Density
  16. Page Size Kilobytes
  17. Term Frequency
  18. TF/IDF
  19. Word Count