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Gemma 3 12B IT vs GPT OSS 20B

Close to a tie overall. GPT OSS 20B costs 23% less for the same work, and both read a 128K-token context.

Gemma 3 12B IT

by Google · #59 of 67 overall

Coming soon · price at launch
Context
128K
Input / 1M
$0.050
Output / 1M
$0.15

GPT OSS 20B

by OpenAI · #58 of 67 overall

Coming soon · price at launch
Context
128K
Input / 1M
$0.030
Output / 1M
$0.14

Better overall

About even

Grade 35.0 vs 36.3

Cheaper

GPT OSS 20B

23% less, $0.058 vs $0.075 blended

Larger context

Same

128K vs 128K tokens

Head to head

Public benchmarks. Longer is better; each value links to its source.

LMArena TextElo-style rating · LMArena (CC BY 4.0) · Oct 28, 2026
LMArena CodingElo-style rating · LMArena (CC BY 4.0) · Oct 28, 2026
SWE-bench Verified% of issues resolved · SWE-bench · Aug 5, 2025 · reference
Gemma 3 12B ITGemma 3 12B IT: —

Gemma 3 12B ITGPT OSS 20Bv = reported by the model’s maker. — = no public score yet. Arena bars span the range across every model we grade.

What it costs you

Drag to match your monthly usage.

Gemma 3 12B IT$16.00 /month
GPT OSS 20B$11.60 /month

GPT OSS 20B saves you $4.40 a month at this usage, $52.80 a year.

At a glance

AttributeGemma 3 12B ITGPT OSS 20B
Made byGoogleOpenAI
AvailabilityComing soonComing soon
Overall gradeGood · 35.0Good · 36.3
Overall rank#59 of 67#58 of 67
Input price$0.050 per 1M$0.030 per 1M
Output price$0.15 per 1M$0.14 per 1M
Context window131,072 tokens131,072 tokens
Reasoning levelsNoYes
Reads imagesYesNo
Model IDgemma-3-12b-itgpt-oss-20b

Try both with one key

Same endpoint, same key, both hosted in the USA. Change one word to switch models, in Claude Code, Cursor, Cline or your own code.

Get your API key
# Ask either model the same thing
curl https://fullsendai.com/v1/chat/completions \
  -H "Authorization: Bearer $FULLSEND_API_KEY" \
  -d '{"model": "gemma-3-12b-it", "messages": [...]}'

# …then swap one word
  -d '{"model": "gpt-oss-20b", "messages": [...]}'

Questions

Is Gemma 3 12B IT or GPT OSS 20B better?

They grade within two points of each other (35.0 and 36.3), so pick on price and the benchmarks that match your work.

Which is cheaper, Gemma 3 12B IT or GPT OSS 20B?

GPT OSS 20B: $0.030 in and $0.14 out per million tokens, against $0.050 and $0.15 through FullsendAI.

Which has the larger context window?

Neither: both take 131,072 tokens.

Can I use both with one API key?

Yes, once they launch: both are coming soon, at the prices shown, and both will use the same FullsendAI key.

Model rankingsAll benchmarksCompare other models

Scores: LMArena (CC BY 4.0), SWE-bench, and model makers’ published results where marked v. Prices are FullsendAI’s, per million tokens. Data as of Oct 28, 2026.