AI model comparison

Solar Mini 4 vs gpt-oss-20b

Side by side comparison of Solar Mini 4 and gpt-oss-20b on pricing, benchmark scores, context window, and more.

Solar Mini 4 is Upstage's compact, cost-efficient language model, a 35B-parameter mixture-of-experts with 3B active parameters and a 524K context window.

Input / 1M
$0.05
Output / 1M
$0.20
Context
524K

gpt-oss-20b is an open-weight 21B parameter model released by OpenAI under the Apache 2.0 license.

Input / 1M
$0.02
Output / 1M
$0.09
Context
131K

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At a glance

Quick verdict

How the two models stack up on the things people ask about most.

Lower price

openai logo

gpt-oss-20b

2.5x cheaper for a typical chat

Higher intelligence score

Not available

Not enough benchmark data

Larger context window

upstage logo

Solar Mini 4

524K vs 131K tokens

Newer release

upstage logo

Solar Mini 4

Released September 23, 2026

Benchmarks

Benchmark scores

Independent scores from Artificial Analysis. Higher is better.

Intelligence index

upstage logoSolar Mini 4Not available
openai logogpt-oss-20bNot available

Coding index

upstage logoSolar Mini 4Not available
openai logogpt-oss-20b20.7

Agentic index

upstage logoSolar Mini 4Not available
openai logogpt-oss-20b1.2

Pricing

Solar Mini 4 vs gpt-oss-20b API pricing

Per-token API rates. Cheaper option highlighted.

Metricupstage logoSolar Mini 4openai logogpt-oss-20b
Input tokensPer 1M tokens$0.05$0.02
Output tokensPer 1M tokens$0.20$0.09
Cached input (read)Per 1M tokens$0.01$0.01
Cache writePer 1M tokensNot availableNot available

What it costs in practice

Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.

Chat message

2K in, 500 out

upstage logoSolar Mini 4$0.20
openai logogpt-oss-20b$0.08

Coding task

30K in, 4K out

upstage logoSolar Mini 4$2.30$0.95 cached
openai logogpt-oss-20b$0.90$0.63 cached

Long document summary

150K in, 2K out

upstage logoSolar Mini 4$7.90$1.15 cached
openai logogpt-oss-20b$2.88$1.53 cached

Specs

Context window and capabilities

How much each model can read, how much it can write, and what it accepts as input.

Metricupstage logoSolar Mini 4openai logogpt-oss-20b
Context window524K tokens131K tokens
Max output131K tokens33K tokens
Input typesTextText
Output typesTextText
Reasoning effort levelsMax, Extra high, High, Medium, Low, Minimal, NoneHigh, Medium, Low
Default reasoning effortMediumMedium
Release dateSeptember 23, 2026August 5, 2025

Features

Supported features

API features available for each model.

Metricupstage logoSolar Mini 4openai logogpt-oss-20b
Tool callingSupportedSupported
Structured outputsSupportedSupported
JSON modeSupportedSupported
ReasoningSupportedSupported
TemperatureSupportedSupported
Stop sequencesNot supportedSupported
Deterministic seedNot supportedSupported
Verbosity controlNot supportedNot supported

Our take

gpt-oss-20b is 2.5x cheaper for a typical chat. Solar Mini 4 has the larger context window (524K vs 131K tokens). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.

FAQ

Frequently asked questions

Is Solar Mini 4 or gpt-oss-20b cheaper?

gpt-oss-20b is cheaper for a typical chat (2K input tokens and 500 output tokens). gpt-oss-20b costs $0.02 per 1M input tokens and $0.09 per 1M output tokens, while Solar Mini 4 costs $0.05 per 1M input tokens and $0.20 per 1M output tokens.

Which has a bigger context window, Solar Mini 4 or gpt-oss-20b?

Solar Mini 4 supports up to 524K tokens of context, compared with 131K for gpt-oss-20b.

Can I use Solar Mini 4 and gpt-oss-20b at the same time?

Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see Solar Mini 4 and gpt-oss-20b answer side by side and keep the better response.

upstage logoopenai logo

Why choose? Ask both.

Send one prompt to Solar Mini 4 and gpt-oss-20b at the same time. Compare the answers side by side and keep the best one.