Claude Haiku 4.5 vs Gemini 2.5 Flash

Pricing math

Provider list price: Haiku 4.5 is $1.00/M input and $5.00/M output. Flash is $0.30/M input and $2.50/M output. On OpenKey that's price x 1.03: Haiku becomes $1.03/M input and $5.15/M output; Flash becomes $0.309/M input and $2.575/M output.

For a 10M-input / 2M-output workload, the platform's computed costs are $20.00 for Haiku 4.5 and $8.00 for Flash — Flash is 2.5x cheaper for this exact mix. The input price ratio alone is 3.33x (Haiku costs 3.33x more per input token).

Cache pricing also favors Flash: cache reads are $0.03/M on Flash versus $0.10/M on Haiku, and cache writes are $0.083333/M on Flash versus $1.25/M on Haiku. If your workload leans on prompt caching (repeated system prompts, long few-shot contexts), Flash's cache economics beat Haiku's on every line, not just the base rate.

Context and long-document work

Flash's 1,048,576-token context window is roughly 5.2x larger than Haiku's 200,000 tokens (context ratio 0.19, i.e., Haiku holds about 19% of Flash's window). Max output is close: 65,535 tokens for Flash vs 64,000 for Haiku. If you're processing long documents, large codebases, or multi-file context in a single call, Flash's window gives you more room before you have to chunk or summarize. Haiku's 200K window is still generous for most single-document or multi-turn chat use cases, just not for whole-repo or book-length inputs.

Modality and tooling

Flash accepts text, image, file, audio, and video input; Haiku accepts text, image, and file. If your app needs to process audio transcripts or video frames directly, Flash is the only option of the two — Haiku has no audio or video input modality listed. On the tool side, Haiku supports `top_k` as a sampling parameter (Flash doesn't), and Flash supports `seed` for reproducible outputs (Haiku doesn't). Both support `tools`, `tool_choice`, `structured_outputs`, and `reasoning`/`include_reasoning` params, so both work for agentic and structured-output workflows.

Coding and agentic signal

Artificial Analysis benchmarks are only available for Haiku 4.5 in this data: intelligence index 29.6, coding index 43.9, agentic index 16.4. No equivalent Artificial Analysis scores are recorded for Flash, so a direct index-to-index comparison isn't possible here. On Design Arena's coding-adjacent categories, both models are close: Haiku scores 1164 elo (rank 63) on codecategories, Flash scores 1153 elo (rank 69) on the same category — Haiku edges ahead by 11 elo points and 6 ranks, though both sit well outside the top tier.

When to pick each

Pick Flash by default for cost-sensitive, high-volume, or long-context workloads — it's cheaper on every price line (input, output, cache read, cache write) and handles 5x more context. Pick Haiku 4.5 when you're already in the Anthropic ecosystem, need `top_k` sampling control, or the codecategories elo edge (1164 vs 1153) matters more than a 2.5x cost difference for your specific workload.

Questions

Which model is cheaper for cache-heavy workloads?

Gemini 2.5 Flash. Its cache read price is $0.03/M and cache write is $0.083333/M, both well below Claude Haiku 4.5's $0.10/M cache read and $1.25/M cache write. Flash wins on every pricing line, not just base input/output rates.

How much does context length differ between the two?

Gemini 2.5 Flash supports 1,048,576 tokens of context versus Claude Haiku 4.5's 200,000 — a context ratio of 0.19, meaning Haiku's window is about 19% the size of Flash's. Max output tokens are close: 65,535 for Flash, 64,000 for Haiku.

What does a real workload cost on each model?

For 10M input tokens and 2M output tokens, OpenKey pricing works out to $20.00 on Claude Haiku 4.5 and $8.00 on Gemini 2.5 Flash — Flash costs 2.5x less for that exact mix, driven mainly by a 3.33x lower input price.

Does either model handle audio or video?

Only Gemini 2.5 Flash does. Its input modalities include text, image, file, audio, and video. Claude Haiku 4.5's input modalities are limited to text, image, and file — no audio or video support in this data.