GPT-5 mini vs Grok 4.20 beta 0309 Reasoning

GPT-5 mini vs Grok 4.20 beta 0309 Reasoning: GPT-5 mini is cheaper by 88% on average. GPT-5 mini from OpenAI (272,000-token context, reasoning, tool calls) vs. Grok 4.20 beta 0309 Reasoning from xAI (2,000,000-token context, reasoning, tool calls). Use Agent Command Center to A/B both in shadow mode and pick the winner per workload.

Side-by-side cost

Live workload comparison

Same workload run through both models. The cheaper one is highlighted.

3,000
02,000,000
400
0200,000
5,000
01,000,000
GPT-5 miniCheaper
OpenAI
$236/mo
Input $0.250/M · Output $2.00/M
xAI
$1,278/mo
Input $2.00/M · Output $6.00/M
At this workload, GPT-5 mini is 82% cheaper than Grok 4.20 beta 0309 Reasoning — a savings of $1,042/month ($12,510/year).
Production recipe — Agent Command Center
strategy: cost-optimized
primary:
  model: gpt-5-mini
  provider: openai
fallback:
  model: grok-4-20-beta-0309-reasoning
  provider: xai
shadow: { sample_rate: 0.05 }   # mirror 5% of traffic to compare quality live
GPT-5 mini Grok 4.20 beta 0309 Reasoning
xAI
Input price $0.250/M $2.00/M
Output price $2.00/M $6.00/M
Context window 272,000 2,000,000
Max output 128,000 2,000,000
Function calling
Vision
Audio input
Reasoning
Prompt caching
Structured output
Pricing verified May 12, 2026 May 12, 2026
Cheaper option
~88% cheaper than Grok 4.20 beta 0309 Reasoning
Larger context
2,000,000 tokens
More capabilities
5 of 6 capability flags advertised

Benchmark comparison

Side-by-side public benchmark scores. Greener bar = winner.

Chatbot Arena ELOgeneral
GPT-5 mini
1,395
Grok 4.20 beta 0309 Reasoning
1,477
HumanEvalcode
GPT-5 mini
93.5%
Grok 4.20 beta 0309 Reasoning
AIME 2024math
GPT-5 mini
91.1%
Grok 4.20 beta 0309 Reasoning
MMLU-Proreasoning
GPT-5 mini
82.0%
Grok 4.20 beta 0309 Reasoning
GPQA Diamondreasoning
GPT-5 mini
78.4%
Grok 4.20 beta 0309 Reasoning
SWE-bench Verifiedagent
GPT-5 mini
68.0%
Grok 4.20 beta 0309 Reasoning