Model comparison
GPT-5.3 Instant vs o3
Head-to-head evidence from 0 shared benchmark results across 0 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.3 Instant #60 (Estimated); o3 #131 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.3 Instant and o3 share 0 comparable benchmark results. 0 of 8 categories are comparable. 0 results are unique to GPT-5.3 Instant; 16 to o3.
Updated July 18, 2026- Shared results
- 0
- GPT-5.3 Instant only
- 0
- o3 only
- 16
- Comparable categories
- 0 / 8
Benchmark data for GPT-5.3 Instant and o3 is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 0 shared benchmark results across 0 evidence categories; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
BenchLM does not have sourced benchmark coverage for GPT-5.3 Instant yet. This comparison is currently limited to metadata such as context window, reasoning mode, and pricing where available.
GPT-5.3 Instant is priced at $1.75 input / $14.00 output per 1M tokens, versus $2.00 input / $8.00 output per 1M tokens for o3. GPT-5.3 Instant has the larger context window at 400K, compared with 200K for o3.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.3 Instant | o3 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.3 Instant$1.75 input / $14 output | o3$2 input / $8 output | o3 has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.3 InstantNot available | o3118 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.3 InstantNot available | o35.38 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.3 Instant400K | o3200K | GPT-5.3 Instant lists the larger context window. |
Benchmark Deep Dive
Agentic1 benchmarks
| Benchmark | GPT-5.3 Instant | o3 | Result |
|---|---|---|---|
| τ²-bench resultsSource | — | 80.7% | Not comparable |
Coding1 benchmarks
| Benchmark | GPT-5.3 Instant | o3 | Result |
|---|---|---|---|
| AA-SciCodeSource | — | 41.0% | Not comparable |
Reasoning2 benchmarks
Knowledge6 benchmarks
| Benchmark | GPT-5.3 Instant | o3 | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | — | 30.4% | Not comparable |
| AA-GPQA DiamondSource | — | 82.7% | Not comparable |
| AA-HLESource | — | 20.0% | Not comparable |
| AA-Omniscience IndexSource | — | -15.3% | Not comparable |
| AA-Omniscience AccuracySource | — | 38.4% | Not comparable |
| AA-Omniscience Hallucination RateSource | — | 87.1% | Not comparable |
Math3 benchmarks
Multimodal2 benchmarks
Inst. Following1 benchmarks
| Benchmark | GPT-5.3 Instant | o3 | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 71.4% | Not comparable |
Frequently Asked Questions (3)
Can I compare GPT-5.3 Instant and o3 on BenchLM yet?
Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.
Why does this comparison show “coming soon”?
BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.
What data is available for GPT-5.3 Instant and o3 today?
GPT-5.3 Instant: $1.75 input / $14.00 output per 1M tokens o3: $2.00 input / $8.00 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
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