Skip to content
Rapid Router

Model comparison

Gemma 3 4B IT vs GPT OSS 20B

Gemma 3 4B IT (Google) and GPT OSS 20B (OpenAI) side by side: what each costs per million tokens through Rapid Router, how much context each takes, what each supports, and where independent benchmarks place them. Same API, same key; switching is a one-string change.

Gemma 3 4B ITGPT OSS 20B
Input price per 1M$0.050$0.030
Output price per 1M$0.100$0.140
Context window131K tokens131K tokens
Max output16K tokens16K tokens
Input typestext, imagetext
CapabilitiesJSON, visiontools, reasoning
AuthorGoogleOpenAI

What a month costs on each

WorkloadGemma 3 4B ITGPT OSS 20B
Chatbot month (15M in, 4M out)$1.15$1.01
RAG month (40M in, 3M out)$2.30$1.62
Coding month (60M in, 10M out)$4.00$3.20

On a typical 75/25 input-output mix, GPT OSS 20B costs less (about 8% less than Gemma 3 4B IT). Gemma 3 4B IT takes the longer prompt at 131K tokens. Try your own numbers in the cost calculator.

Call either one

curl https://rapidrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $RAPIDROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "google/gemma-3-4b-it:free", "messages": [{"role": "user", "content": "Hello"}]}'

# the other one: change the model string
  -d '{"model": "openai/gpt-oss-20b:free", ...}'

Common questions

Which is cheaper, Gemma 3 4B IT or GPT OSS 20B?

GPT OSS 20B is cheaper on a typical mix of 75% input and 25% output tokens, by about 8%. Through Rapid Router both are billed at the provider list price per million tokens.

Which has the larger context window?

Gemma 3 4B IT, at 131K tokens. GPT OSS 20B offers 131K tokens.

Can I switch between Gemma 3 4B IT and GPT OSS 20B without changing code?

Yes. Both are callable at https://rapidrouter.ai/api/v1 with the same OpenAI-compatible request; only the model string changes (google/gemma-3-4b-it:free or openai/gpt-oss-20b:free).

How do I pay for Gemma 3 4B IT or GPT OSS 20B?

Top up a Rapid Router balance by card in US dollars, and both models debit that balance per request.

More Gemini models: Google API pricing · More GPT: OpenAI API pricing