GPT-5.2 vs Grok 4.3
GPT-5.2 (OpenAI, released 2025-12-10) and Grok 4.3 (xAI, released 2026-04-30) both handle text, image, and file input with text-only output, and both support optional reasoning effort levels. The gap that matters: GPT-5.2 charges 1.4x more per input token and caps context at 400K, while Grok 4.3 runs a 1M-token window at roughly 38% of GPT-5.2's blended workload cost. Benchmark data narrows the decision to a tradeoff between per-task quality and per-token price.
Spec vs spec
| Spec | GPT-5.2 | Grok 4.3 |
|---|---|---|
| Context window | 400K | 1M |
| Max output | 128K | — |
| Input modalities | file, image, text | text, image, file |
| Output modalities | text | text |
| Released | Dec 10, 2025 | Apr 30, 2026 |
| Reasoning | optional | optional |
Pricing
Per 1M tokens. Provider price plus the flat 3% fee — the sum is what you pay.
openai/gpt-5.2
Input · 1M tokens
$1.75 + 3%$1.80
Output · 1M tokens
$14.00 + 3%$14.42
Cache read · 1M tokens
$0.175 + 3%$0.180
FEE — FLAT, EVERY MODEL3%
x-ai/grok-4.3
Input · 1M tokens
$1.25 + 3%$1.29
Output · 1M tokens
$2.50 + 3%$2.58
Cache read · 1M tokens
$0.200 + 3%$0.206
FEE — FLAT, EVERY MODEL3%
One workload, priced on both
10M input + 2M output tokens at each model's price, flat 3% fee included.
openai/gpt-5.2
$46.87
$45.50 provider + 3%
x-ai/grok-4.3Cheaper
$18.03
$17.50 provider + 3%
Benchmarks
Design Arena categories where both models have results. Higher Elo and lower rank win.
| GPT-5.2 | Grok 4.3 | |||
|---|---|---|---|---|
| Category | Elo | Rank | Elo | Rank |
| 3D | 1156 | #60 | 1202 | #43 |
| androidnative | 1074 | #22 | 1074 | #23 |
| ASCII art | 1199 | #22 | 1189 | #27 |
| Code | 1219 | #42 | 1243 | #31 |
| Data viz | 1245 | #31 | 1234 | #35 |
| Full-stack | 1110 | #21 | 1072 | #26 |
| Game dev | 1260 | #29 | 1242 | #34 |
| godotgamedev | 1183 | #13 | 1134 | #16 |
| Mobile apps | 1173 | #23 | 1146 | #26 |
| SVG | 1197 | #31 | 1140 | #44 |
| UI components | 1243 | #32 | 1250 | #31 |
| Web apps | 1156 | #19 | 1194 | #14 |
| Websites | 1237 | #34 | 1244 | #31 |
Head-to-head preference voting. How we filter and rank
Pricing math
Provider list price for GPT-5.2 is $1.75/M input and $14.00/M output; on OpenKey that's $1.8025/M input and $14.42/M output after the flat 3% fee ($1.75 x 1.03, $14.00 x 1.03). Grok 4.3 lists at $1.25/M input and $2.50/M output, or $1.2875/M and $2.575/M on OpenKey. Run the numbers on a 10M-input / 2M-output workload and GPT-5.2 costs $45.50 versus $17.50 for Grok 4.3 — a 2.6x difference driven almost entirely by GPT-5.2's output rate, which is 5.6x higher than Grok's ($14.00 vs $2.50 per million). Cache-read pricing is close: $0.175/M for GPT-5.2 vs $0.20/M for Grok 4.3, so caching doesn't change the ranking.
Coding and agent benchmarks
Both models were scored on Design Arena's agent and model categories, giving a direct comparison. GPT-5.2 ranks better in most agentic coding tasks: fullstack rank 21 (elo 1110) vs Grok's rank 26 (elo 1072), mobile apps rank 23 (elo 1173) vs Grok's rank 26 (elo 1146), and android native — a tie at rank... actually GPT-5.2 ranks 22 (elo 1074) vs Grok's rank 23 (elo 1074), same elo score but GPT-5.2 edges the rank. Grok 4.3 pulls ahead on web apps, ranking 14 (elo 1194) against GPT-5.2's rank 19 (elo 1156). On raw model categories, Grok scores higher elo in code (1243 vs 1219) and data viz (1234 vs 1245 is close, GPT-5.2 slightly ahead there), but Grok's win rates trail in several categories — its intelligence_index (37.6), coding_index (42.2), and agentic_index (24.1) from Artificial Analysis give additional context not available for GPT-5.2 in this dataset.
Context and long-document work
Grok 4.3's 1,000,000-token context window is 2.5x GPT-5.2's 400,000 tokens (context ratio 0.4, GPT-5.2 relative to Grok). For processing long codebases, large log files, or multi-document RAG pipelines without chunking, Grok 4.3 has more room. GPT-5.2's max completion length is capped at 128,000 tokens; Grok 4.3 has no stated max_completion_tokens limit in this data, which matters if you need very long single-turn outputs rather than just large inputs.
When to pick each
Pick GPT-5.2 when the task is agentic coding — fullstack builds, mobile app scaffolding, Android native work — where its Design Arena ranks beat Grok's in the same categories. Pick Grok 4.3 when cost per token or context window size is the binding constraint: it's 2.6x cheaper on a 10M/2M workload and holds 2.5x the context. Both models run through OpenKey with a single API key and a flat 3% fee on top of provider list pricing, so switching between them for A/B testing doesn't require separate account setup.
Which model for which job
| Use case | Pick | Why |
|---|---|---|
| Full-stack coding agent | GPT-5.2 | Ranks 21 vs Grok's 26 on Design Arena's fullstack agent category |
| Long-document / large codebase analysis | Grok 4.3 | 1M-token context vs GPT-5.2's 400K |
| High-volume production workload | Grok 4.3 | $17.50 vs $45.50 for the same 10M-in/2M-out workload |
| Mobile app development agent | GPT-5.2 | Rank 23 (elo 1173) vs Grok's rank 26 (elo 1146) on mobile apps |
| Web app generation | Grok 4.3 | Rank 14 (elo 1194) beats GPT-5.2's rank 19 (elo 1156) on webapps |
| Cost-sensitive output-heavy tasks | Grok 4.3 | Output tokens priced at $2.50/M vs GPT-5.2's $14.00/M |
Questions
- Which model is cheaper to run?
- Grok 4.3, by a wide margin. On a 10M-input / 2M-output workload it costs $17.50 versus $45.50 for GPT-5.2. The gap comes mostly from output pricing: $2.50/M for Grok 4.3 vs $14.00/M for GPT-5.2 — a 5.6x difference on the completion side.
- Which has the bigger context window?
- Grok 4.3 supports 1,000,000 tokens of context, 2.5x GPT-5.2's 400,000-token window. If you're feeding in large codebases or long transcripts without chunking, Grok 4.3 gives you more headroom before you hit the limit.
- Is GPT-5.2 better at coding?
- It depends on the task type. GPT-5.2 ranks ahead on fullstack (rank 21 vs 26) and mobile apps (rank 23 vs 26) in Design Arena's agent tests, but Grok 4.3 ranks ahead on web apps (rank 14 vs 19). Neither wins across the board.
- Can I use both models with one API key?
- Yes. OpenKey provides access to both GPT-5.2 and Grok 4.3 through a single key across its catalog of 329 models, charging provider list price plus a flat 3% fee — so GPT-5.2's $1.75/M input becomes $1.8025/M and Grok 4.3's $1.25/M becomes $1.2875/M.