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Model vs model

Claude Sonnet 5 vs Gemini 3.8 Flash

Claude Sonnet 5 and Gemini 3.8 Flash are both in llmwise. What each gets on every plan, what it reads, how it's served and what happens when its provider fails, from the catalog and the code that runs them.

Model prices and specs checked against OpenRouter's Claude Sonnet 5 page, OpenRouter's Gemini 3.8 Flash page. Updated .

Short answer

Gemini 3.8 Flash gets twice as many messages: up to 250 messages a month on Pro, against up to 125 messages a month for Claude Sonnet 5. Beyond that, they read the same files and neither is easier to try. In our test runs, Claude Sonnet 5 passed 46 of the 50 prompts both answered and Gemini 3.8 Flash 46; 6 prompts split them, most on summarization (3 to 5).

Claude Sonnet 5 vs Gemini 3.8 Flash, prompt by prompt

Every prompt Claude Sonnet 5 and Gemini 3.8 Flash both answered, compared directly, their biggest differences first. One run each, through OpenRouter: a wait depends on the provider and the load that day, so a lead under 10% counts as close.

Of the 50 prompts both answered, both passed 43, only Claude Sonnet 5 passed 3, only Gemini 3.8 Flash passed 3, and neither passed 1. Claude Sonnet 5 answered sooner on 31 of the 50 and Gemini 3.8 Flash on 14; the rest were within 10% of each other. The 50 replies cost $0.2030 on Claude Sonnet 5 and $0.0644 on Gemini 3.8 Flash: 3.2× less on Gemini 3.8 Flash.

The 6 prompts only one of Claude Sonnet 5 and Gemini 3.8 Flash passed

  • Announce a second bakery shop on LinkedIn (writing): Gemini 3.8 Flash passed and Claude Sonnet 5 didn't. Claude Sonnet 5: Graded 3.5 of 5 on average (lowest 3). Gemini 3.8 Flash: Graded 4.5 of 5 on average (lowest 4).

  • Rewrite corporate jargon in plain words (writing): Claude Sonnet 5 passed and Gemini 3.8 Flash didn't. Claude Sonnet 5: Graded 4.7 of 5 on average (lowest 4). Gemini 3.8 Flash: Graded 3.7 of 5 on average (lowest 3).

  • A product announcement with five rules (writing): Claude Sonnet 5 passed and Gemini 3.8 Flash didn't. Claude Sonnet 5: Graded 4.3 of 5 on average (lowest 4). Gemini 3.8 Flash: Graded 3.7 of 5 on average (lowest 3).

  • An article in three bullets (summarization): Gemini 3.8 Flash passed and Claude Sonnet 5 didn't. Claude Sonnet 5: Graded 3.7 of 5 on average (lowest 3). Gemini 3.8 Flash: Graded 4.3 of 5 on average (lowest 4).

  • An email thread in one sentence (summarization): Gemini 3.8 Flash passed and Claude Sonnet 5 didn't. Claude Sonnet 5: Graded 5.0 of 5 on average (lowest 5); but 32 words, over the 30 allowed. Gemini 3.8 Flash: Graded 4.7 of 5 on average (lowest 4).

  • A frustrated customer (customer support): Claude Sonnet 5 passed and Gemini 3.8 Flash didn't. Claude Sonnet 5: Graded 4.3 of 5 on average (lowest 4). Gemini 3.8 Flash: Graded 3.0 of 5 on average (lowest 2).

Job by job, the widest gaps first

  • Summarization: Claude Sonnet 5 passed 3 of 5 and Gemini 3.8 Flash 5 of 5. Claude Sonnet 5 answered 1.4× sooner at the median, 2.7 s against 3.7 s. Gemini 3.8 Flash cost 3.7× less, $0.0140 against $0.0038 for the 5 replies. Claude Sonnet 5's replies ran 48% longer, in tokens of reply, thinking not counted.

  • Writing: Claude Sonnet 5 passed 4 of 5 and Gemini 3.8 Flash 3 of 5. Gemini 3.8 Flash answered 1.1× sooner at the median, 4.5 s against 3.9 s. Gemini 3.8 Flash cost 2.6× less, $0.0171 against $0.0066 for the 5 replies. Claude Sonnet 5's replies ran 68% longer, in tokens of reply, thinking not counted.

  • Customer support: Claude Sonnet 5 passed 5 of 5 and Gemini 3.8 Flash 4 of 5. Their median waits were close, 3.5 s against 3.7 s. Gemini 3.8 Flash cost 2.2× less, $0.0182 against $0.0082 for the 5 replies. Claude Sonnet 5's replies ran 58% longer, in tokens of reply, thinking not counted.

  • Coding: Claude Sonnet 5 passed 5 of 5 and Gemini 3.8 Flash 5 of 5. Claude Sonnet 5 answered 1.6× sooner at the median, 2.7 s against 4.2 s. Gemini 3.8 Flash cost 5.2× less, $0.0508 against $0.0098 for the 5 replies. Claude Sonnet 5's replies ran 11% longer, in tokens of reply, thinking not counted.

  • Translation: Claude Sonnet 5 passed 5 of 5 and Gemini 3.8 Flash 5 of 5. Their median waits were close, 2.8 s against 3.0 s. Gemini 3.8 Flash cost 4.0× less, $0.0149 against $0.0037 for the 5 replies. Claude Sonnet 5's replies ran 67% longer, in tokens of reply, thinking not counted.

  • SQL: Claude Sonnet 5 passed 5 of 5 and Gemini 3.8 Flash 5 of 5. Claude Sonnet 5 answered 1.7× sooner at the median, 2.2 s against 3.7 s. Gemini 3.8 Flash cost 3.8× less, $0.0142 against $0.0037 for the 5 replies. Claude Sonnet 5's replies ran 32% longer, in tokens of reply, thinking not counted.

  • RAG and answering from documents: Claude Sonnet 5 passed 5 of 5 and Gemini 3.8 Flash 5 of 5. Claude Sonnet 5 answered 1.7× sooner at the median, 1.8 s against 3.1 s. Gemini 3.8 Flash cost 3.3× less, $0.0109 against $0.0033 for the 5 replies. Their replies ran to about the same length.

  • Agents and tool use: Claude Sonnet 5 passed 5 of 5 and Gemini 3.8 Flash 5 of 5. Claude Sonnet 5 answered 2.2× sooner at the median, 2.0 s against 4.4 s. Gemini 3.8 Flash cost 2.8× less, $0.0121 against $0.0043 for the 5 replies. Claude Sonnet 5's replies ran 34% longer, in tokens of reply, thinking not counted.

  • Data analysis: Claude Sonnet 5 passed 4 of 5 and Gemini 3.8 Flash 4 of 5. Their median waits were close, 5.3 s against 5.4 s. Gemini 3.8 Flash cost 2.5× less, $0.0344 against $0.0138 for the 5 replies. Gemini 3.8 Flash's replies ran 189% longer, in tokens of reply, thinking not counted.

  • Math: Claude Sonnet 5 passed 5 of 5 and Gemini 3.8 Flash 5 of 5. Claude Sonnet 5 answered 1.2× sooner at the median, 3.9 s against 4.7 s. Gemini 3.8 Flash cost 2.3× less, $0.0165 against $0.0071 for the 5 replies. Gemini 3.8 Flash's replies ran 16% longer, in tokens of reply, thinking not counted.

All 50 prompts: who passed, who answered sooner, who cost less
Claude Sonnet 5 and Gemini 3.8 Flash on each prompt of our test runs
PromptResultSoonerCheaper
Turn a title into a URL slugBoth passedClaude Sonnet 5, 1.8×took 2.3 s and 4.2 sGemini 3.8 Flash, 2.8×cost $0.0024 and $0.0009
Parse a duration like “1h 30m”Both passedGemini 3.8 Flash, 1.1×took 2.6 s and 2.3 sGemini 3.8 Flash, 3.5×cost $0.0036 and $0.0010
Merge overlapping intervalsBoth passedClaude Sonnet 5, 1.4×took 2.7 s and 3.8 sGemini 3.8 Flash, 2.8×cost $0.0034 and $0.0012
Evaluate an arithmetic expression, no evalBoth passedGemini 3.8 Flash, 2.5×took 16.9 s and 6.7 sGemini 3.8 Flash, 5.1×cost $0.0226 and $0.0045
Parse CSV with quoted fieldsBoth passedGemini 3.8 Flash, 3.2×took 15.8 s and 5.0 sGemini 3.8 Flash, 8.6×cost $0.0187 and $0.0022
Announce a second bakery shop on LinkedInOnly Gemini 3.8 FlashGemini 3.8 Flash, 1.2×took 4.6 s and 3.9 sGemini 3.8 Flash, 4.1×cost $0.0037 and $0.0009
Rewrite corporate jargon in plain wordsOnly Claude Sonnet 5Claude Sonnet 5, 1.2×took 2.7 s and 3.1 sGemini 3.8 Flash, 3.5×cost $0.0022 and $0.0006
Decline a meeting and offer two timesBoth passedClaude Sonnet 5, 1.3×took 2.8 s and 3.5 sGemini 3.8 Flash, 3.3×cost $0.0026 and $0.0008
A product announcement with five rulesOnly Claude Sonnet 5Claude Sonnet 5, 1.7×took 4.5 s and 7.6 sGemini 3.8 Flash, 1.1×cost $0.0035 and $0.0031
Argue both sides of free busesBoth passedGemini 3.8 Flash, 1.3×took 6.6 s and 5.2 sGemini 3.8 Flash, 4.5×cost $0.0050 and $0.0011
A discount, then sales taxBoth passedClaude Sonnet 5, 1.3×took 1.9 s and 2.5 sGemini 3.8 Flash, 2.3×cost $0.0015 and $0.0007
Pens at 3 for $4Both passedGemini 3.8 Flash, 1.4×took 6.3 s and 4.7 sGemini 3.8 Flash, 3.7×cost $0.0061 and $0.0017
Compound interest over three yearsBoth passedGemini 3.8 Flash, 1.8×took 3.7 s and 2.1 sGemini 3.8 Flash, 2.4×cost $0.0021 and $0.0009
Four-digit numbers whose digits sum to 9Both passedClosetook 4.5 s and 4.7 sGemini 3.8 Flash, 1.8×cost $0.0039 and $0.0022
The highest of three dice is a 5Both passedClaude Sonnet 5, 1.2×took 3.9 s and 4.9 sGemini 3.8 Flash, 1.6×cost $0.0028 and $0.0018
An article in three bulletsOnly Gemini 3.8 FlashClaude Sonnet 5, 1.4×took 2.6 s and 3.7 sGemini 3.8 Flash, 3.7×cost $0.0027 and $0.0007
An email thread in one sentenceOnly Gemini 3.8 FlashClaude Sonnet 5, 1.7×took 2.3 s and 3.8 sGemini 3.8 Flash, 3.6×cost $0.0019 and $0.0005
Decisions and action items from a meetingBoth passedClaude Sonnet 5, 1.1×took 2.8 s and 3.2 sGemini 3.8 Flash, 3.5×cost $0.0033 and $0.0009
A quarterly memo for the CEOBoth passedClaude Sonnet 5, 1.4×took 3.0 s and 4.0 sGemini 3.8 Flash, 3.6×cost $0.0033 and $0.0009
A study with a negative resultBoth passedClaude Sonnet 5, 1.3×took 2.7 s and 3.6 sGemini 3.8 Flash, 4.2×cost $0.0028 and $0.0007
The region with the most revenueBoth passedClaude Sonnet 5, 1.1×took 6.4 s and 7.4 sClosecost $0.0041 and $0.0038
Average order value in AugustBoth passedClaude Sonnet 5, 1.1×took 3.9 s and 4.4 sGemini 3.8 Flash, 2.5×cost $0.0041 and $0.0016
Revenue change from July to AugustBoth passedClaude Sonnet 5, 1.2×took 5.3 s and 6.6 sGemini 3.8 Flash, 1.7×cost $0.0062 and $0.0037
A median, filtered two waysBoth passedGemini 3.8 Flash, 1.4×took 4.9 s and 3.5 sGemini 3.8 Flash, 3.4×cost $0.0036 and $0.0010
Correlation between ad spend and sign-upsNeither passedGemini 3.8 Flash, 2.6×took 13.8 s and 5.4 sGemini 3.8 Flash, 4.4×cost $0.0165 and $0.0037
A late orderBoth passedGemini 3.8 Flash, 1.1×took 3.5 s and 3.1 sGemini 3.8 Flash, 3.9×cost $0.0036 and $0.0009
A return inside the windowBoth passedClosetook 2.9 s and 2.9 sGemini 3.8 Flash, 3.8×cost $0.0032 and $0.0009
A frustrated customerOnly Claude Sonnet 5Gemini 3.8 Flash, 1.2×took 4.4 s and 3.7 sGemini 3.8 Flash, 3.8×cost $0.0041 and $0.0011
A refund request outside the windowBoth passedClaude Sonnet 5, 1.9×took 3.2 s and 5.9 sGemini 3.8 Flash, 1.1×cost $0.0031 and $0.0029
A message with a planted instructionBoth passedClaude Sonnet 5, 1.6×took 4.6 s and 7.3 sGemini 3.8 Flash, 1.7×cost $0.0041 and $0.0025
A delivery message into SpanishBoth passedClaude Sonnet 5, 1.4×took 2.7 s and 3.7 sGemini 3.8 Flash, 3.8×cost $0.0029 and $0.0008
A product description into FrenchBoth passedGemini 3.8 Flash, 1.1×took 2.5 s and 2.2 sGemini 3.8 Flash, 3.8×cost $0.0029 and $0.0008
A meeting note into GermanBoth passedClosetook 2.8 s and 3.0 sGemini 3.8 Flash, 4.3×cost $0.0027 and $0.0006
Idioms into natural JapaneseBoth passedClaude Sonnet 5, 1.2×took 4.1 s and 4.7 sGemini 3.8 Flash, 3.6×cost $0.0028 and $0.0008
A lease clause into Brazilian PortugueseBoth passedGemini 3.8 Flash, 1.8×took 3.8 s and 2.0 sGemini 3.8 Flash, 4.5×cost $0.0036 and $0.0008
Customers in one countryBoth passedClaude Sonnet 5, 1.7×took 1.8 s and 3.1 sGemini 3.8 Flash, 4.2×cost $0.0020 and $0.0005
Count orders by statusBoth passedClaude Sonnet 5, 1.9×took 2.0 s and 3.7 sGemini 3.8 Flash, 4.2×cost $0.0020 and $0.0005
Revenue by categoryBoth passedGemini 3.8 Flash, 1.2×took 3.5 s and 3.0 sGemini 3.8 Flash, 4.0×cost $0.0031 and $0.0008
Every customer, even those without ordersBoth passedClaude Sonnet 5, 1.7×took 2.2 s and 3.7 sGemini 3.8 Flash, 3.8×cost $0.0030 and $0.0008
Monthly revenue with a running totalBoth passedClaude Sonnet 5, 1.5×took 3.0 s and 4.7 sGemini 3.8 Flash, 3.4×cost $0.0042 and $0.0012
A fact from one sectionBoth passedClaude Sonnet 5, 1.9×took 1.7 s and 3.1 sGemini 3.8 Flash, 3.4×cost $0.0019 and $0.0006
Core hours and start timesBoth passedClaude Sonnet 5, 1.4×took 2.1 s and 2.9 sGemini 3.8 Flash, 3.4×cost $0.0022 and $0.0006
Two sections in one answerBoth passedClaude Sonnet 5, 1.7×took 1.8 s and 3.1 sGemini 3.8 Flash, 3.4×cost $0.0022 and $0.0006
A later amendment changes the answerBoth passedClaude Sonnet 5, 1.9×took 2.1 s and 4.1 sGemini 3.8 Flash, 3.0×cost $0.0026 and $0.0009
A question the handbook doesn't answerBoth passedClaude Sonnet 5, 1.6×took 1.8 s and 2.9 sGemini 3.8 Flash, 3.4×cost $0.0019 and $0.0006
Pick the tool and work out the dateBoth passedClosetook 1.7 s and 1.9 sGemini 3.8 Flash, 3.5×cost $0.0018 and $0.0005
Convert a currencyBoth passedClaude Sonnet 5, 2.2×took 2.0 s and 4.4 sGemini 3.8 Flash, 2.4×cost $0.0018 and $0.0008
Book a meeting from a sentenceBoth passedClaude Sonnet 5, 1.1×took 5.7 s and 6.3 sGemini 3.8 Flash, 3.1×cost $0.0037 and $0.0012
Search, but don't bookBoth passedClaude Sonnet 5, 3.4×took 1.9 s and 6.3 sGemini 3.8 Flash, 2.2×cost $0.0020 and $0.0009
Two calls with a unit conversionBoth passedClosetook 3.8 s and 3.9 sGemini 3.8 Flash, 2.9×cost $0.0028 and $0.0010

Claude Sonnet 5 vs Gemini 3.8 Flash in our test runs

Claude Sonnet 5 and Gemini 3.8 Flash on the same prompts, job by job: how many replies passed their check.

Based on 100 of our test runs on , through OpenRouter with the app's own prompt and settings. Updated .

Claude Sonnet 5 and Gemini 3.8 Flash in our test runs, job by job
JobClaude Sonnet 5Gemini 3.8 Flash
Coding5 of 55 of 5
Writing4 of 53 of 5
Math5 of 55 of 5
Summarization3 of 55 of 5
Data analysis4 of 54 of 5
Customer support5 of 54 of 5
Translation5 of 55 of 5
SQL5 of 55 of 5
RAG and answering from documents5 of 55 of 5
Agents and tool use5 of 55 of 5
All jobs46 of 50 · 1 message each · $0.0041 a reply46 of 50 · 1 message each · $0.0013 a reply

The same prompts, sent to both through llmwise's own pipeline and checked the same way: five for each job. A bold count is the one that passed more. Messages: what each reply counted as on Pro. Cost: what OpenRouter charged us per reply, on average. Every prompt, and how it's scored.

Where they differed most, summarization: both replies to a prompt only one of them passed.

An everyday prompt: “An article in three bullets”, in full.

  • Claude Sonnet 5

    Failed: Graded 3.7 of 5 on average (lowest 3).

    - Aldmoor's 6-month trial bike lanes tripled cyclist trips (900→2,300/day), cut car traffic 14%, but added ~1 min to rush-hour drives.
    
    - Business impact mixed: 27 of 60 shops saw more customers, 19 fewer.
    
    - Injuries dropped (9→2); permanent install would cost €1.1M more.

    725 tokens in, 125 out · 2.6 s · $0.0027 · 1 message on Pro · answered by anthropic/claude-sonnet-5 via Claude Platform on AWS ·

  • Gemini 3.8 Flash

    Passed: Graded 4.3 of 5 on average (lowest 4).

    * Aldmoor's six-month trial increased daily bike trips from 900 to 2,300 and reduced cyclist injuries from nine to two.
    * Car traffic fell 14% with minor delays, while local shop owners reported mixed impacts on customer numbers.
    * The city council votes in November on making the lanes permanent, which would cost €1.1 million.

    560 tokens in, 81 out · 3.7 s · $0.0007 · 1 message on Pro · answered by google/gemini-3.8-flash via Google ·

Claude Sonnet 5 and Gemini 3.8 Flash on every plan

Whether the one-time free trial reaches each model, then each paid plan's messages on it.

Messages on Claude Sonnet 5 and Gemini 3.8 Flash, plan by plan
PlanPriceClaude Sonnet 5Gemini 3.8 Flash
Free$0In the one-time trial of 5 messagesIn the one-time trial of 5 messages
Pro$20 a monthUp to 125 a monthUp to 250 a month
Max$50 a monthUp to 400 a monthUp to 800 a month
Ultra$100 a monthUp to 900 a monthUp to 1,800 a month
Studio$200 a monthUp to 2,000 a monthUp to 4,000 a month

Prices don't include tax, which is added where it applies and shown before you pay. A paid plan's month is one allowance shared by every model, so each monthly count is the most you get if all of it goes to that model. It renews each billing period; everyday models refill daily at 00:00 UTC. Long chats count more per reply. How pricing works.

Every limit is published. Paid plans also have a monthly fair-use limit on AI cost: Pro $7.50, Max $20, Ultra $42, Studio $85. Using every message on your plan at typical sizes stays under it; very large messages and heavy research use it faster. Every limit, explained.

What differs

  • Messages on Pro

    Gemini 3.8 Flash gets twice as many messages: up to 250 messages a month on Pro, against up to 125 messages a month for Claude Sonnet 5.

  • Context window

    Claude Sonnet 5 takes up to 1M tokens; Gemini 3.8 Flash up to 1.05M tokens. A chat in llmwise holds up to 200k tokens, which fits in either, so the difference shows only through each maker's own API.

  • Images and PDFs

    Both read images. Both take a PDF as the whole file, pages and all.

  • On Free

    Both are in the free trial.

  • Where messages go

    Claude Sonnet 5: Sent to Anthropic directly. Gemini 3.8 Flash: Sent to Google directly.

Fact by fact

Claude Sonnet 5 and Gemini 3.8 Flash, fact by fact
FactClaude Sonnet 5Gemini 3.8 Flash
Context window1M tokens1.05M tokens
Reads imagesYesYes
PDFsWhole fileWhole file
ReasoningYesYes
API price (September 2026)$2.00 in / $10.00 out per million tokens$0.75 in / $3.75 out per million tokens
A typical message at API prices (4,000 tokens in, 700 out)$0.0150$0.0056
A $10 top-up adds100 messages200 messages
Where a message goesSent to Anthropic directly.Sent to Google directly.
If the provider failsIf Anthropic fails before the reply starts (an overload, a server error, a dropped connection), llmwise sends the same request to Claude Sonnet 5 through OpenRouter instead.If Google fails before the reply starts (an overload, a server error, a dropped connection), llmwise sends the same request to Gemini 3.8 Flash through OpenRouter instead.
Anthropic's safety fallbackDoesn't applyDoesn't apply
API prices are what our model catalog lists (Claude: Anthropic's list price; Gemini: Google's list price). In llmwise you pay per message, not per token: the counts above are what you get.

Claude Sonnet 5 or Gemini 3.8 Flash?

From the facts above and our test runs: the rest is how their answers suit your work, which one chat can show you.

  • Pick Gemini 3.8 Flash: more messages for the money, up to 250 messages a month on Pro.

Each model's page, the families, and other pairs

Claude Sonnet 5 vs Gemini 3.8 Flash is one pair of models. The page below covers the whole families.

Questions

Is Claude Sonnet 5 or Gemini 3.8 Flash cheaper in llmwise?

Gemini 3.8 Flash gets twice as many messages: up to 250 messages a month on Pro, against up to 125 messages a month for Claude Sonnet 5. Every paid plan's monthly allowance is shared by all models, so each count is the most you get if it all goes to that model.

Can I try Claude Sonnet 5 and Gemini 3.8 Flash for free?

Yes: both are in the free trial of 5 messages.

Which has the bigger context window, Claude Sonnet 5 or Gemini 3.8 Flash?

Gemini 3.8 Flash: 1.05M tokens, against 1M tokens. A chat in llmwise holds up to 200k tokens, which fits in either, so the difference shows only through each maker's own API.

Can I use Claude Sonnet 5 and Gemini 3.8 Flash in the same chat?

Yes. Pick Claude Sonnet 5 for one message and Gemini 3.8 Flash for the next; the second sees the whole chat, including the first one's answer.

Which did better in your test runs, Claude Sonnet 5 or Gemini 3.8 Flash?

On the same 50 prompts, run on September 27, 2026, Claude Sonnet 5 passed 46 and Gemini 3.8 Flash passed 46. The table on this page has each job, and every reply is published.

Claude, GPT, Gemini, DeepSeek, Grok, Kimi, and GLM, in one chat.

See what a message costs before you send it. Free is 5 messages to try; sign in with an email link, no password or card.