Which model is better: Gemini 2.5 Flash or GPT-4.5?

**Gemini 2.5 Flash delivers a massive price-performance advantage over GPT-4.5.** It is 99.6% cheaper for input tokens at $0.30 versus $75.00 per 1M tokens ($2.50 vs. $150.00 output). Additionally, Gemini 2.5 Flash is 740ms faster with a 110ms TTFT and leads coding benchmarks with 58.0% on SWE-bench compared to GPT-4.5's 38.0%.
Verified daily via automated API latency tests and official documentation.

Verified Performance & Unit Economics Delta

Daily synchronized metrics from synthetic latency endpoints and benchmark evaluations.

Metric / Dimension Gemini 2.5 Flash GPT-4.5 Net Delta / Advantage
Input Cost / 1M Tokens $0.30 $75.00 Gemini 2.5 Flash is 250.0x cheaper
Output Cost / 1M Tokens $2.50 $150.00 Gemini 2.5 Flash (98.3% lower)
Prompt Cache Read / 1M $0.030 $37.500 Gemini 2.5 Flash is 1250.0x cheaper
Prompt Cache Write / 1M $0.30 $75.00 Gemini 2.5 Flash is 250.0x cheaper
Avg TTFT Response Latency 110ms 850ms Gemini 2.5 Flash (+740ms faster)
SWE-bench Verified (Coding) 58% 38% Gemini 2.5 Flash (+20.0% lead)
Inference Value Score (IVR) 66.8 / 100 22.1 / 100 Gemini 2.5 Flash (+44.7 pts)

Interactive Monthly Token Economics & ROI Forecaster

Model your expected production workload across prompt (input) and completion (output) tokens with prompt caching economics.

Live Calculation Engine
10.0M Tokens
100K 50M 250M 500M+
2.5M Tokens
100K 10M 50M 100M+

Estimated Monthly Spend

Gemini 2.5 Flash $9.25

$0.30/1M in · $2.50/1M out

Prompt Cache: $0.030/1M read · $0.30/1M write

GPT-4.5 $1,125.00

$75.00/1M in · $150.00/1M out

Prompt Cache: $37.500/1M read · $75.00/1M write

Projected Monthly Cost Reduction
$1,115.75 / mo
(99.2% lower cost with Gemini 2.5 Flash)
A

When to Choose Gemini 2.5 Flash

Choose Gemini 2.5 Flash when you need Hybrid reasoning model delivering unmatched price-performance across 1M context with configurable thinking budgets. and have an infrastructure budget aligned with $0.30/1M tokens.

B

When to Choose GPT-4.5

Choose GPT-4.5 when you need Deep world-knowledge synthesis, high-EQ conversational nuance, and long-form creative generation requiring massive pretraining breadth. and prioritize OpenAI ecosystem integration at $75.00/1M tokens.

Related Questions & Decision Factors

Which is cheaper: Gemini 2.5 Flash or GPT-4.5?

Gemini 2.5 Flash is cheaper at $0.30/1M input tokens compared to $75.00/1M for GPT-4.5.

Which model has lower latency: Gemini 2.5 Flash or GPT-4.5?

Gemini 2.5 Flash delivers faster response times with an average TTFT of 110ms vs 850ms for GPT-4.5.

When should you choose Gemini 2.5 Flash?

Choose Gemini 2.5 Flash when you need Hybrid reasoning model delivering unmatched price-performance across 1M context with configurable thinking budgets. and have an infrastructure budget aligned with $0.30/1M tokens.

When should you choose GPT-4.5?

Choose GPT-4.5 when you need Deep world-knowledge synthesis, high-EQ conversational nuance, and long-form creative generation requiring massive pretraining breadth. and prioritize OpenAI ecosystem integration at $75.00/1M tokens.

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