AI Model Cost Comparison Calculator (Two Models)
Compare two LLM providers' pricing side by side at your actual monthly input/output token volume.
Inputs
- Monthly Input Tokens (millions)
- Monthly Output Tokens (millions)
- Model A: Input Price per Million
- Model A: Output Price per Million
- Model B: Input Price per Million
- Model B: Output Price per Million
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Saved Scenarios
— select 2+ to compare| Metric | |
|---|---|
Model A Monthly Cost
$375.00
Model B Monthly Cost
$47.50
Difference (A − B)
$327.50
Cheaper Model's Savings
87.3%
Spark says
How it's calculated
Formula
- InputPrice, OutputPrice
- — Each model's separately-priced rate per million input and output tokens
What is the AI Model Cost Comparison Calculator (Two Models)?
This calculator compares two LLM providers' or models' pricing side by side at your actual monthly input and output token volume, since separately-priced input and output rates mean the cheaper model at one usage mix isn't always cheaper at another.
Use this when choosing between LLM providers or specific model tiers for a new project, re-evaluating an existing model choice against a newer or cheaper alternative, or understanding how your specific input-to-output token ratio affects which model is genuinely cheaper for your use case.
How to use it
- 1 Enter your expected monthly input and output token volumes separately, in millions.
- 2 Enter both models' input and output prices per million tokens.
- 3 Read each model's total monthly cost and the exact dollar and percentage difference.
Understanding AI Model Cost Comparison Calculator (Two Models)
Comparing LLM pricing across models or providers is more nuanced than comparing a single headline price, because nearly every provider prices input and output tokens separately, and often at meaningfully different rates — output tokens commonly cost several times more per token than input tokens, reflecting the different computational work involved in generating new text versus processing existing text as context.
This separate pricing structure means the specific ratio of input to output tokens in your actual usage pattern directly determines which of two models comes out cheaper, and this ratio varies considerably by task type. A summarization or document-analysis task, characterized by a long input (the document being summarized) and a comparatively short output (the summary itself), is a fundamentally input-dominated cost profile, meaning the input price difference between two models matters more than the output price difference for that specific use case. A creative-writing, code-generation, or long-form content task, by contrast, is often output-dominated — a short prompt producing a long generated response — meaning output pricing differences matter considerably more for that task's total cost. Two models that appear similarly priced when only their input rates are compared can therefore differ substantially in real total cost once your specific task's actual token ratio is applied.
This is exactly why a genuine cost comparison needs your own actual usage data rather than an assumed or generic ratio — pulling real input and output token counts from your application's logs, if it's already running, or making a careful task-specific estimate for a new project, gives a comparison that actually reflects your real cost exposure rather than a generic industry assumption that may not match your specific use case at all.
Cost, importantly, is only one dimension of a genuine model choice, and a cost comparison should never be the sole factor without also validating quality on your specific task. A meaningfully cheaper model that produces lower-quality output for your particular use case — requiring more retries, more post-processing, or more human review to reach an acceptable result — can end up costing more in total once these hidden downstream costs are factored in, even though its raw per-token price looks more attractive in isolation. A sound model choice pairs a genuine cost comparison like this calculator provides with a genuine quality evaluation on representative examples of your actual task, treating cost as one important input to the decision rather than the only one.
Finally, given how frequently the LLM pricing landscape shifts — new models launching, existing models being repriced, older models being deprecated — treating any specific cost comparison as a point-in-time snapshot worth periodically re-running, rather than a permanent conclusion, is the practically sound way to keep a production system's model choice genuinely cost-optimized over time rather than locked into a decision made under since-outdated pricing.
Worked examples
50M in / 15M out tokens, Model A $3/$15, Model B $0.50/$1.50
Model A costs $375.00/month; Model B costs $47.50/month — Model B is about 87.3% cheaper.
Try it200M in / 50M out tokens, Model A $3/$15, Model B $0.50/$1.50
Model A costs $1,350.00/month; Model B costs $175.00/month — the gap grows at higher volume.
Try itAdvantages
- •Accounts for separate input and output pricing, which a single blended-rate comparison misses.
- •Uses your actual token mix, since the cheaper model depends on your specific input-to-output ratio, not a generic assumption.
- •Shows both dollar difference and percentage savings for different reporting needs.
- •Works for any two models or providers by entering their specific published rates.
Limitations
- •Compares pricing only — doesn't account for quality, latency, context window size, or other capability differences between models that matter for choosing the right one for a specific task.
Common mistakes
- ⚠️ Comparing models using only one price point (often just the more commonly cited input price) while ignoring output price, when output tokens are often priced several times higher than input and can dominate total cost for output-heavy tasks.
- ⚠️ Assuming a cheaper-per-token model is always the better overall choice without checking whether it can actually complete your specific task with acceptable quality — a lower-cost model that requires more retries or produces worse results can end up costing more in practice.
- ⚠️ Using an industry-average or someone else's input-to-output token ratio instead of your own actual usage pattern, when the ratio genuinely changes which model comes out cheaper.
Tips
- 💡 Which price matters more, input or output? It depends entirely on your task's input-to-output ratio — a summarization task with long input and short output is dominated by input price, while a creative-writing task with a short prompt and long output is dominated by output price.
- 💡 Calculate your own actual input-to-output token ratio from real usage logs rather than guessing, since this ratio directly determines which model is cheaper for your specific case.
- 💡 Always pair a cost comparison with a quality comparison on your actual task before switching models purely for cost savings, since a cheaper model that needs more retries or produces lower-quality output isn't a genuine net win.
- 💡 Re-run this comparison periodically, since model pricing changes relatively frequently as providers release new models and adjust existing pricing.
Real-life uses
- Choosing between LLM providers or specific model tiers for a new project
- Re-evaluating an existing model choice against a newer or cheaper alternative
- Understanding how your specific input-to-output token ratio affects which model is genuinely cheaper for your use case
- Building a cost justification for migrating a production workload to a different model
Frequently asked questions
Which price matters more, input or output?
It depends on your task's input-to-output ratio — input-heavy tasks like summarization are dominated by input price, while output-heavy tasks like creative writing are dominated by output price.
Should I use my own usage data for this comparison?
Yes — calculate your actual input-to-output token ratio from real usage logs rather than guessing, since this ratio directly determines which model is cheaper for your specific case.
Is the cheaper model always the better choice?
Not necessarily — always pair a cost comparison with a quality comparison on your actual task, since a cheaper model needing more retries or producing worse output can cost more overall.
How often should I re-run a model cost comparison?
Periodically — LLM pricing changes relatively frequently as providers release new models and adjust existing pricing, so treat any comparison as a point-in-time snapshot.
Does this calculator account for quality or capability differences?
No — it compares pricing only; quality, latency, context window size, and other capabilities should be evaluated separately before choosing a model.
calixo.cloud/ai/ai-model-cost-comparison-calculator/ — free calculator, no signup required.