API cost decision in 10 seconds

o3 Mini vs GPT-5.5 Pro

Pick o3 Mini for lower cost; pick GPT-5.5 Pro only if the larger context window matters more.

Page updated: 2026-05-26T15:08:08Z Data confirmed: 2026-05-26T18:08:02Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick o3 Mini for lower cost; pick GPT-5.5 Pro only if the larger context window matters more.

On the standard 1M input plus 500K output workload, o3 Mini is estimated at $3.3 vs $120 for GPT-5.5 Pro, saving $116.7 (97.2% lower).

Cost-first picko3 Mini

Context-first pickGPT-5.5 Pro

Sample savings$116.797.2%

10x traffic gap$1167

GPT-5.5 Pro has more context, but o3 Mini saves $116.7 on the standard workload. At 10x that traffic, the same price gap is about $1167. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

o3 Mini stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	o3 Mini	GPT-5.5 Pro
Input-heavy / RAG	5M input + 500K output	o3 Mini	$7.7	$240
Balanced workload	1M input + 1M output	o3 Mini	$5.5	$210
Output-heavy chatbot	1M input + 5M output	o3 Mini	$23.1	$930

Cheaper input o3 Mini $1.1 vs $30 / 1M

o3 Mini is $28.9 cheaper per 1M input tokens (96.3% lower; 27.3x difference).

Cheaper output o3 Mini $4.4 vs $180 / 1M

o3 Mini is $175.6 cheaper per 1M output tokens (97.6% lower; 40.9x difference).

Larger context GPT-5.5 Pro 200K vs 1.05M

GPT-5.5 Pro has 850K more context (5.25x larger).

Sample workload o3 Mini $3.3 vs $120

o3 Mini is $116.7 cheaper on the standard workload (97.2% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

o3 Mini Calculating… Estimated API cost

GPT-5.5 Pro Calculating… Estimated API cost

Cheaper for this workload Calculating… 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

o3 Mini has the lower input price; o3 Mini has the lower output price; GPT-5.5 Pro offers the larger context window. For the 1M input plus 500K output sample, o3 Mini is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $3.3 for o3 Mini and $120 for GPT-5.5 Pro.

Best Fit

Choose o3 Mini when you care most about lower input-token price, and lower output-token price.

Choose GPT-5.5 Pro when you care most about larger context window.

Decision Notes

On the standard 1M input plus 500K output workload, o3 Mini is estimated at $3.3 vs $120 for GPT-5.5 Pro, saving $116.7 (97.2% lower).
o3 Mini is $116.7 cheaper on the standard workload (97.2% lower).
o3 Mini is $28.9 cheaper per 1M input tokens (96.3% lower; 27.3x difference).
o3 Mini is $175.6 cheaper per 1M output tokens (97.6% lower; 40.9x difference).
GPT-5.5 Pro has 850K more context (5.25x larger).

Head-to-Head Specs

Feature	o3 Mini (OpenAI)	GPT-5.5 Pro (OpenAI)
Input Price prompt tokens per 1M	$1.1	$30
Completion Price per 1M tokens	$4.4	$180
Sample Workload Cost 1M input + 500K output	$3.3	$120
Context Window	200K	1.05M
Release Date	2025-01-31	2026-04-24
Popularity	#120	#122

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	o3 Mini	On the standard 1M input plus 500K output workload, o3 Mini is estimated at $3.3 vs $120 for GPT-5.5 Pro, saving $116.7 (97.2% lower).
High-volume input processing	o3 Mini	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	o3 Mini	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	GPT-5.5 Pro	A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps

gpt-oss-120b (free) can replace o3 Mini when lower sample workload cost matters most: $0.
gpt-oss-20b (free) can replace o3 Mini when lower sample workload cost matters most: $0.
gpt-oss-20b can replace o3 Mini when lower sample workload cost matters most: $0.1.
gpt-oss-120b can replace o3 Mini when lower sample workload cost matters most: $0.13.

Larger context near this budget

Llama 4 Scout offers 10M context with $0.23 sample workload cost.
Grok 4.20 offers 2M context with $2.5 sample workload cost.
Grok 4.20 Multi-Agent offers 2M context with $5 sample workload cost.

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Provider catalogs

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OpenAI catalog

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Open OpenAI models

o3 Mini

OpenAI o3-mini is a cost-efficient language model optimized for STEM reasoning tasks, particularly excelling in science, mathematics, and coding. This model supports the `reasoning_effort` parameter, which can be set to...

GPT-5.5 Pro

GPT-5.5 Pro is OpenAI’s high-capability model optimized for deep reasoning and accuracy on complex, high-stakes workloads. It features a 1M+ token context window (922K input, 128K output) with support for...