tokevenGPTvsGrok
GPT 5.5 vs Grok 4.20 Reasoning
Side-by-side comparison of pricing, task quality, and projected cost at higher scale.
Pricing
Side-by-side pricing
GPT 5.5
FlagshipGrok 4.20 Reasoning
Mid-tierInput $/MTok
$5.00
$1.25
Output $/MTok
$30.00
$2.50
Cache discount
90% off
84% off
Context
1,050K
1,000K
Quality
Task confidence comparison
Confidence score from zero to one hundred by task type, where higher is better.
Code Generation
91
vs
0
Code Review
90
vs
0
Summarization
89
vs
0
Q&A
90
vs
0
Extraction
87
vs
0
Reasoning
95
vs
0
Classification
85
vs
0
Creative Writing
91
vs
0
GPT 5.5
Grok 4.20 Reasoning
Guidance
When to use GPT 5.5 vs Grok 4.20 Reasoning
Choose GPT 5.5 when...
- -You need a larger context window (1,050K vs 1,000K)
- Similar performance; consider provider preference or ecosystem fit.
Choose Grok 4.20 Reasoning when...
- -Cost matters: 75% cheaper on input tokens
At scale
Cost at scale
Estimated cost assuming a seventy percent input and thirty percent output token split.
GPT 5.5
Grok 4.20 Reasoning
100K tokens
$1.25
$0.16Cheaper
1M tokens
$20.50
$3.25Cheaper
10M tokens
$205.00
$32.50Cheaper
FAQ
When should I use GPT 5.5 instead of Grok 4.20 Reasoning?
GPT 5.5 and Grok 4.20 Reasoning perform similarly across all tracked tasks. Pick based on pricing and provider preference.
Is Grok 4.20 Reasoning cheaper than GPT 5.5?
Yes. Grok 4.20 Reasoning input costs $1.25/MTok vs $5.00/MTok for GPT 5.5, saving 75% on input.
What are the context window sizes for GPT 5.5 and Grok 4.20 Reasoning?
GPT 5.5 has a 1,050K token context window. Grok 4.20 Reasoning has a 1,000K token context window.
Go deeper on either model
Per-call cost calculators, provider lineups, and price history for both models on this page.
Other comparisons
How GPT 5.5 and Grok 4.20 Reasoning stack up against the rest of the field.
Track your real costs
Comparisons show estimated costs at list price. The dashboard reveals your real spend and savings.