API cost decision in 10 seconds

GPT-5.3-Codex vs 🔥Gemini 3 Flash Preview

Pick Gemini 3 Flash Preview when budget and context both matter.

Pricing data updated:  Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Gemini 3 Flash Preview when budget and context both matter.

On the standard 1M input plus 500K output workload, Gemini 3 Flash Preview is estimated at $2 vs $8.75 for GPT-5.3-Codex, saving $6.75 (77.1% lower).

Cost-first pickGemini 3 Flash Preview
Context-first pickGemini 3 Flash Preview
Sample savings$6.7577.1%
10x traffic gap$67.5

Gemini 3 Flash Preview is cheaper on the standard workload and also has the larger context window. At 10x that traffic, the same price gap is about $67.5. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Gemini 3 Flash Preview stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shapeToken mixBetter pickGPT-5.3-CodexGemini 3 Flash Preview
Input-heavy / RAG 5M input + 500K output Gemini 3 Flash Preview $15.75 $4
Balanced workload 1M input + 1M output Gemini 3 Flash Preview $15.75 $3.5
Output-heavy chatbot 1M input + 5M output Gemini 3 Flash Preview $71.75 $15.5
Cheaper inputGemini 3 Flash Preview$1.75 vs $0.5 / 1M
Cheaper outputGemini 3 Flash Preview$14 vs $3 / 1M
Larger contextGemini 3 Flash Preview400K vs 1.05M
Sample workloadGemini 3 Flash Preview$8.75 vs $2

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.
GPT-5.3-CodexCalculating…Estimated API cost
Gemini 3 Flash PreviewCalculating…Estimated API cost
Cheaper for this workloadCalculating…Difference: calculating…

This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.

Quick Decision

Verdict

Gemini 3 Flash Preview has the lower input price, Gemini 3 Flash Preview has the lower output price, and Gemini 3 Flash Preview offers the larger context window.

For a 1M input token plus 500K output token workload, the estimated API cost is $8.75 for GPT-5.3-Codex and $2 for Gemini 3 Flash Preview.

Best Fit

Choose GPT-5.3-Codex when its provider, model quality, latency, or availability is more important than the numeric price/context winner.

Choose Gemini 3 Flash Preview when you care most about lower input-token price, lower output-token price, and larger context window.

Head-to-Head Specs
FeatureGPT-5.3-Codex
(OpenAI)		🔥Gemini 3 Flash Preview
(Google)
Input Price
prompt tokens per 1M		$1.75$0.5
Completion Price
per 1M tokens		$14$3
Sample Workload Cost
1M input + 500K output		$8.75$2
Context Window400K1.05M
Release Date2026-02-242025-12-17
Popularity#7
GPT-5.3-Codex

GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, combining the frontier software engineering performance of GPT-5.2-Codex with the broader reasoning and professional knowledge capabilities of GPT-5.2. It achieves state-of-the-art results...

Gemini 3 Flash Preview

Gemini 3 Flash Preview is a high speed, high value thinking model designed for agentic workflows, multi turn chat, and coding assistance. It delivers near Pro level reasoning and tool...

Use-Case Decision Matrix

Use caseBetter pickWhy
Budget-constrained productionGemini 3 Flash PreviewOn the standard 1M input plus 500K output workload, Gemini 3 Flash Preview is estimated at $2 vs $8.75 for GPT-5.3-Codex, saving $6.75 (77.1% lower).
High-volume input processingGemini 3 Flash PreviewLower prompt-token price matters most when prompts or retrieved passages dominate the bill.
Long responses and chatbotsGemini 3 Flash PreviewLower output-token price matters most when assistants generate many completion tokens.
RAG or long-document workGemini 3 Flash PreviewA larger context window leaves more room for retrieved passages and source files.