GPT 5.5 vs Grok 4.20 Multi Agent Beta pricing
Side-by-side token pricing for GPT 5.5 (OpenAI) and Grok 4.20 Multi Agent Beta (xAI), plus the total cost at three workload sizes so the crossover point is obvious. Prices refreshed 2026-09-23 00:10 UTC.
| Metric | GPT 5.5 | Grok 4.20 Multi Agent Beta |
|---|---|---|
| Input $/1M tokens | $5 | $1.25 |
| Output $/1M tokens | $30 | $2.5 |
| Cached input $/1M | $0.5 | $0.2 |
| Context window | 1.1M | 1M |
| Max output | 128K | 1M |
| Vision | yes | yes |
| Tool calling | yes | no |
| Cache pricing | yes | yes |
Total cost by workload
| Workload | GPT 5.5 | Grok 4.20 Multi Agent Beta | Cheaper |
|---|---|---|---|
| 1M tokens in · 300K out | $14 | $2 | Grok 4.20 Multi Agent Beta (86% less) |
| 10M tokens in · 3M out | $140 | $20 | Grok 4.20 Multi Agent Beta (86% less) |
| 100M tokens in · 30M out | $1400 | $200 | Grok 4.20 Multi Agent Beta (86% less) |
On blended cost (weighted 3:1 toward input), Grok 4.20 Multi Agent Beta comes out cheaper by roughly 75% on input pricing. Pick Grok 4.20 Multi Agent Beta when the workload is price-sensitive and its context window covers your prompts; GPT 5.5 is the one to benchmark if you need vision, reasoning depth, or a different quality profile.
Frequently asked
› Is GPT 5.5 cheaper than Grok 4.20 Multi Agent Beta?
On input pricing, Grok 4.20 Multi Agent Beta is cheaper ($1.25 vs $5 per 1M tokens). On blended cost the winner is Grok 4.20 Multi Agent Beta, because output tokens are weighted differently for most workloads.
› Which has the larger context window?
GPT 5.5 offers the larger context (1.1M tokens).
› Do these prices include prompt caching?
Cached input is priced separately where a provider publishes a cache rate; the table above lists it per model so the comparison stays like-for-like.