A phone number field cuts LinkedIn form completion by 66%.
In the same account, LinkedIn lead gen forms that ask for a phone number complete 66% less often than forms that do not, and cost 135% more per lead. It is the one field that measurably moves completion.
By Phil Ilic · Published 19 Oct 2026 · From Kiin Labs Report No. 3, LinkedIn Lead Gen Forms Benchmarks
| Fields on the form | 3 or fewer | 4 | 5 | 6 | 7 | 8+ |
|---|---|---|---|---|---|---|
| Completion, all | 9.0% | 9.9% | 6.7% | 6.2% | 7.6% | 4.0% |
| Content | 15.1% | 15.3% | 8.8% | 8.2% | 12.0% | 13.0% |
| Demo | 2.7% | 1.5% | 3.4% | 1.8% | 1.3% | 2.0% |
Median feed completion by field count, cross-panel. Paired short (5 or fewer) vs long (7 or more): +16%, not significant, 14 accounts. Source: Kiin Labs Report No. 3.
Kiin Labs (2026). Adding a phone number field to a LinkedIn lead gen form cuts completion by 66% (95% interval −83% to −46%; 27 accounts) and raises cost per lead by 135% (+51% to +331%; 23 accounts) in the same account, 8 Sep 2025 to 7 Sep 2026. https://kiin.co/research/linkedin-lead-form-phone-number
Embed this chart
Phone number only when sales will dial it.
By offer
On content offers, a phone field cuts completion by 53% across 12 accounts. On demo offers the drop is 13% and not significant across 8 accounts.
Field count barely matters
Cross-panel, 3 or fewer fields complete at 9.0% and 8 or more at 4.0%, but paired inside one account short against long is +16% and not significant. The median form has 6 fields and 35% ask for a phone number.
Why the raw table says the opposite
Across the panel, forms with a phone field look cheaper ($107 against $243 per lead) because the cheapest accounts ask for a phone 59% of the time. The paired comparison inside one account is the number to use.
Where the number comes from
Kiin Labs Report No. 3, chapter 04, 4,875 forms. LinkedIn Ads accounts connected to Kiin Intelligence via the LinkedIn Marketing API, 8 September 2025 to 7 September 2026, converted to USD, LinkedIn Audience Network excluded. Every figure is a median across advertiser accounts, and no cell with fewer than seven accounts is published.
Questions about this number.
Should I ask for a phone number on a LinkedIn lead gen form?
Only if sales will call it. In the same account, a phone field cuts completion by 66% and raises cost per lead by 135%.
Does a phone field hurt LinkedIn demo forms?
Less: completion falls 13% on demo offers, which is not significant across 8 accounts, against 53% on content offers.
How many fields should a LinkedIn lead gen form have?
Field count does not move completion measurably once compared inside one account (+16% short vs long, not significant). The median form has 6 fields.
Which LinkedIn form field hurts completion most?
The phone number. No other field showed a significant effect on completion.
Book a call. Leave with data no other agency can give you.
Your benchmark
Your CPM, CTR, CPC, CPL and cost per demo, next to advertisers buying your audience. From $60M+ of real LinkedIn spend.
Your business case
What LinkedIn should cost for your market, and the pipeline range your budget can realistically buy.
Your first three fixes
The changes that would move your numbers most, ranked by how much spend each one touches.
Running LinkedIn already? We'll bring your benchmark. New to it? We'll build the business case from your ACV and audience.
Not ready to talk? Benchmark your LinkedIn Ads free →