Microsoft Outlook vs Spark:Which is more popular?
In September 2026, Microsoft Outlook had more branded searches than Spark among email clients worldwide. Microsoft Outlook had about 1.2 million branded searches, while Spark had 40,500. Microsoft Outlook made up 83.1% of all email client searches we track, and Spark accounted for 2.8%. When we asked ChatGPT and Google AI Overviews about email clients, Microsoft Outlook appeared in all five answers and Spark in four. Microsoft Outlook was mentioned before Spark in four out of five answers.
Who do people search for more?
Microsoft Outlook, about 30 searches for every 1 for Spark
Who does AI mention more?
Microsoft Outlook, mentioned in every answer we collected
Who does AI recommend more?
Microsoft Outlook, named ahead of Spark in 4 of 5 answers
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Top email clients in ChatGPT and Google AI Overviews
In three ChatGPT questions and two Google AI Overviews, Microsoft Outlook appeared in all five answers. Spark was mentioned in four out of five: in two of the three ChatGPT answers and in both Google AI Overviews. Microsoft Outlook was listed before Spark in four out of five answers.
Most recommended by AI
Brands get a higher ranking if they are mentioned earlier in the answers.
- Microsoft Outlook1st
Apple Mail2nd
Thunderbird3rd
Spark4th
Proton Mail5th
Superhuman6th
Airmail–
Newton–
Mentioned by AI
Each dot is one answer, filled in when that answer mentions the brand.
- Microsoft Outlook5 of 5Named in 3 of 3 ChatGPT answersNamed in 2 of 2 Google answers
- Apple Mail5 of 5Named in 3 of 3 ChatGPT answersNamed in 2 of 2 Google answers
- Spark4 of 5Named in 2 of 3 ChatGPT answersNamed in 2 of 2 Google answers
- Thunderbird4 of 5Named in 3 of 3 ChatGPT answersNamed in 1 of 2 Google answers
- Superhuman3 of 5Named in 2 of 3 ChatGPT answersNamed in 1 of 2 Google answers
- Proton Mail3 of 5Named in 2 of 3 ChatGPT answersNamed in 1 of 2 Google answers
- Airmail0 of 5Named in 0 of 3 ChatGPT answersNamed in 0 of 2 Google answers
- Newton0 of 5Named in 0 of 3 ChatGPT answersNamed in 0 of 2 Google answers
See every answer about email clients
5 answers
Asked ChatGPT
“Which email client should I use?”
Asked ChatGPT
“What are the best email clients?”
Asked ChatGPT
“What's the best email client for daily email management?”
Searched Google, AI Overview
“email client”
Searched Google, AI Overview
“best email app”
Brands are shown in the order each answer named them. The survey took place in the United States on October 20, 2026.
Is Microsoft Outlook or Spark more popular in search?
This chart shows how often people search Google for Microsoft Outlook and Spark by name. Each line represents a brand's share of searches for all eight email clients we track, month by month, from English-language searches worldwide.
Share of searches by month for Microsoft Outlook, Spark. The figures are in the table below the chart.
View monthly share of searches table
| Month | Microsoft Outlook | Apple Mail | Spark | Thunderbird | Superhuman | Airmail | Newton | Proton Mail |
|---|---|---|---|---|---|---|---|---|
| Oct 2025 | 86.7% | 7.8% | 1.3% | 2% | 1.1% | 1.1% | 0.04% | <0.01% |
| Nov 2025 | 84.8% | 9.3% | 1.3% | 2% | 1.5% | 1% | 0.06% | <0.01% |
| Dec 2025 | 81.6% | 11% | 1.5% | 2.5% | 1.7% | 1.5% | 0.11% | <0.01% |
| Jan 2026 | 84.1% | 9.2% | 1.2% | 2.6% | 1.8% | 1% | 0.06% | <0.01% |
| Feb 2026 | 86.4% | 7.8% | 0.85% | 2.3% | 1.9% | 0.7% | 0.06% | <0.01% |
| Mar 2026 | 85.7% | 7.7% | 1% | 2.4% | 2.3% | 0.85% | 0.05% | 0.01% |
| Apr 2026 | 84.4% | 7.6% | 1.3% | 2.9% | 2.7% | 1% | 0.11% | 0.01% |
| May 2026 | 84.9% | 7.7% | 1.3% | 2.6% | 2.7% | 0.85% | 0.05% | 0.01% |
| Jun 2026 | 85.1% | 7.7% | 1.5% | 2.1% | 2% | 1.3% | 0.25% | 0.01% |
| Jul 2026 | 83.5% | 9.2% | 1.5% | 2.6% | 2.1% | 1% | 0.08% | 0.02% |
| Aug 2026 | 83.8% | 9.3% | 1.5% | 2.4% | 1.6% | 1.3% | 0.05% | 0.02% |
| Sep 2026 | 83.1% | 9.2% | 2.8% | 2% | 1.8% | 1% | 0.05% | 0.02% |
How has the Microsoft Outlook and Spark comparison changed over the last 12 months?
3 findings
- Microsoft Outlook was ahead of Spark in every measured month of the 12 months ending September 2026.
- Across the 12 months ending September 2026, Microsoft Outlook’s share of searches among email clients worldwide moved from 86.7% to 83.1%, and its estimated monthly branded searches moved from 1.8M to 1.2M.
- Across the 12 months ending September 2026, Spark’s share of searches among email clients worldwide moved from 1.3% to 2.8%, and its estimated monthly branded searches moved from 27.1K to 40.5K.
How did search popularity change for email clients worldwide in September 2026?
2 changes
In September 2026, Spark overtook Thunderbird and Superhuman to rank 3rd among email clients worldwide, with 2.8% of the searches.
In September 2026, Microsoft Outlook lost share of searches among email clients worldwide, from 83.8% to 83.1%.
How are branded searches counted?
2 search terms
Brandwave collects information about searches that people make online using Microsoft Outlook’s and Spark’s names. When viewed over time, estimated search volumes for these branded terms can be used to understand whether interest in the brands is growing, holding steady, or fading.
Microsoft Outlook
1 branded search term
- microsoft outlook
Spark
1 branded search term
- spark email
Other head-to-heads among email clients
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