Gemini 3.8 Flash vs GPT-6 Luna
Gemini 3.8 Flash and GPT-6 Luna are within three points on the Models at Work leaderboard, which we treat as a tie (65 vs 64 out of 100). On independent tests alone, Gemini 3.8 Flash is ahead (63 vs 39). GPT-6 Luna is cheaper: 1,000 support replies cost about $0.50 at list price, against $3.75 on Gemini 3.8 Flash, which is 7.5 times as much. On the Artificial Analysis Intelligence Index, one of the independent tests, Gemini 3.8 Flash leads 31 to 28.
| Gemini 3.8 Flash · Google | GPT-6 Luna · OpenAI | |
|---|---|---|
| Leaderboard rank | #12 | #14 |
| Score (0–100) | 65 | 64 |
| Kind of work | High-volume work | High-volume work |
| Price per 1M tokens | $0.75 to read · $3.75 to write | $0.10 to read · $0.50 to write |
| Reads at once | 1M tokens (about 750,000 words) | 1M tokens (about 750,000 words) |
| Where you can get it | Gemini Enterprise Agent Platform (Google Cloud), Gemini app (Google AI Pro and Ultra) | OpenAI API, Amazon Bedrock, Microsoft Foundry, Gemini Enterprise Agent Platform (Google Cloud) |
| Can a company host it itself | No | No |
| Artificial Analysis Intelligence Index | 31 | 28 |
| Arena Text score | 1497 (rank 8) | Not measured |
| Scale SWE-Bench Pro V2 (mini-swe-agent) | 58.80% | Not measured |
| Humanity's Last Exam, Diamond (Scale) | 34.30 | Not measured |
| Humanity's Sixth Sense (Scale) | 41.60 | 21.00 |
| Best for | First-pass support replies, Summarising documents, images and recordings at volume, Routine multi-step tasks on a budget | Simple extraction from forms and emails, Short routine replies, Sorting messages |
Cost of 1,000 jobs
| 1,000 of these | Gemini 3.8 Flash | GPT-6 Luna |
|---|---|---|
| Support repliesthe customer message, the account notes and two help articles read; a 300-word reply written | $3.75 | $0.50 |
| Documents processeda two-page invoice or form read; the fields pulled out | $2.63 | $0.35 |
| Calls summariseda 40-minute call transcript read; a summary and next steps written | $9.75 | $1.30 |
| Contracts revieweda 40-page contract read against a checklist; a memo of issues written | $28 | $3.75 |
| Drafts writtena brief and one example read; a 600-word email or proposal section written | $4.13 | $0.55 |
Worked out from each vendor’s list price and a fixed size for each job. A product built on a model charges its own price on top. See what every model costs for the same jobs.
Choose Gemini 3.8 Flash for
- First-pass support replies
- Summarising documents, images and recordings at volume
- Routine multi-step tasks on a budget
Fast and well liked in blind votes for the money, at under half the list price of Gemini 4 Argon, but users report more made-up answers than rivals and Google doubles the price on 1 January 2027.
Caveats: $0.75 in / $3.75 out per million tokens (the unit vendors bill by) is introductory; Google's pricing page says $1.50 / $7.50 from 1 January 2027. Users report more invented facts and more dropped details between messages than with rival models: have someone check its output. Third Flash release in six weeks: expect Google to retire versions quickly and plan for re-testing. In the Gemini app it is for Google AI Pro and Ultra subscribers, per Google's launch post. Google Workspace is not listed: no Google page we read names the model and a Workspace plan.
Choose GPT-6 Luna for
- Simple extraction from forms and emails
- Short routine replies
- Sorting messages
OpenAI's cheapest model, at the same list price as Claude Haiku 5.5 but eight points behind it on Artificial Analysis's index (28 against 36).
Caveats: It ranks 14th largely because price is 30% of the board's score; its test result is low (28 on the index, down from 38 when Artificial Analysis rebuilt it). Users of Haiku 5.5 report it is the noticeably smarter of the two at this price. The release tracker records it as the model behind ChatGPT Free and Go; OpenAI's own page could not be read this run, so ChatGPT is not listed below.
What people running them say
Gemini 3.8 Flash: A very large Hacker News (developer forum) thread: 1,160 upvotes, 669 comments. simonw had it build an interactive chart as a web page in '13 seconds' for '1.8 cents'; colechristensen calls it 'competitive with opus/fable and also FAST'; several use it for the bulk of the work while a stronger model writes the plan. The pushback is about reliability: one user says it 'gives me the most hallucinations' (made-up facts) of the major models, others complain it ignores what was said one message earlier, and in some subjects its knowledge stops at early 2025, which hurts research tasks.
Questions people ask
Which is better, Gemini 3.8 Flash or GPT-6 Luna?
Gemini 3.8 Flash and GPT-6 Luna are within three points on the Models at Work leaderboard, which we treat as a tie (65 vs 64 out of 100). On independent tests alone, Gemini 3.8 Flash is ahead (63 vs 39). GPT-6 Luna is cheaper: 1,000 support replies cost about $0.50 at list price, against $3.75 on Gemini 3.8 Flash, which is 7.5 times as much. On the Artificial Analysis Intelligence Index, one of the independent tests, Gemini 3.8 Flash leads 31 to 28.
When should I choose Gemini 3.8 Flash over GPT-6 Luna?
Choose Gemini 3.8 Flash for first-pass support replies, summarising documents, images and recordings at volume, routine multi-step tasks on a budget. Fast and well liked in blind votes for the money, at under half the list price of Gemini 4 Argon, but users report more made-up answers than rivals and Google doubles the price on 1 January 2027.
When should I choose GPT-6 Luna over Gemini 3.8 Flash?
Choose GPT-6 Luna for simple extraction from forms and emails, short routine replies, sorting messages. OpenAI's cheapest model, at the same list price as Claude Haiku 5.5 but eight points behind it on Artificial Analysis's index (28 against 36).
Which is cheaper, Gemini 3.8 Flash or GPT-6 Luna?
Gemini 3.8 Flash costs $0.75 per million tokens it reads (input) and $3.75 per million tokens it writes (output) on Google's list price (Gemini API Pricing, read Nov 12, 2026). A token is about three-quarters of a word. GPT-6 Luna costs $0.10 per million tokens it reads (input) and $0.50 per million tokens it writes (output) on OpenAI's list price (OpenAI API pricing, read Nov 12, 2026). A token is about three-quarters of a word.
What do 1,000 jobs cost on Gemini 3.8 Flash and GPT-6 Luna?
At list price: 1,000 support replies cost $3.75 on Gemini 3.8 Flash and $0.50 on GPT-6 Luna; 1,000 documents processed cost $2.63 on Gemini 3.8 Flash and $0.35 on GPT-6 Luna; 1,000 calls summarised cost $9.75 on Gemini 3.8 Flash and $1.30 on GPT-6 Luna; 1,000 contracts reviewed cost $28 on Gemini 3.8 Flash and $3.75 on GPT-6 Luna; 1,000 drafts written cost $4.13 on Gemini 3.8 Flash and $0.55 on GPT-6 Luna. A product built on either model charges its own price on top.
Scores come from the Models at Work leaderboard: Score is 0 to 100 and computed, not typed. 40% is independent testing (Artificial Analysis, Arena, Scale, Epoch, Vals and others; each test is scaled against the best score on this board, and tests of real work, such as finished freelance projects or professional tasks, count double the exams). 30% is price: the vendor's list price for a typical mix of reading and writing, on a fixed scale from $0.05 to $60 per million tokens, so a model that costs a fifth as much gains real ground. 15% is what people report after running it, from Signals and linked threads. 15% is fit: how much text it can take in at once and where a business can get it (the products and clouds that carry it), with a small credit for open weights. A missing component drops out and the rest are reweighted. A model with no independent test yet is provisional and ranks below every measured one. Within three points is a tie. Vendor-published figures are labelled and never counted. Prices are vendor list prices where published; a typical mix assumes three parts reading to one part writing.