Corbelworks · LLM Procurement

LLM subscription vs. metered cost calculator

Which is actually cheaper for your workload: a Claude Max, OpenAI Plus, or similar subscription — or paying metered API rates? Enter your real task volume and see the break-even point, subscription efficiency, and landed cost per completed task.

What this calculates. A subscription buys prepaid access with a weekly or monthly cap. A metered API bills per token actually consumed. Which wins depends on your task volume, your completion rate, and how much of the subscription window you can actually fill. This tool does that arithmetic — in your browser, nothing transmitted.

1. Your workload

Task volume

Completions, not attempts. A failed run that retries counts as multiple attempts.
What fraction of attempts produce an accepted result? Lower = more retries = higher effective cost.
Include system prompt, context window, and tool calls.

Time window

Days you'll actually route work. A subscription resets regardless — idle days are waste.
On metered API, cached input tokens cost ~10% of full price. Only applies to metered path.

2. Subscription option

Approximate; subscriptions cap by usage window, not task count. Lower = more conservative estimate of what you can actually burn.
If the subscription tier uses a lighter model than what you'd buy metered, adjust here.
What fraction of the subscription cap do you expect to actually consume? Unused capacity is prepaid waste.

3. Metered API option

Typically ~10% of full input price when caching is available.
Real token spend per task vs. naïve estimate (retries, tool-call overhead, context bloat). 1.15 = 15% overhead.

4. Results

Subscription cost/task
including idle waste
Metered API cost/task
with overhead & retries
Break-even tasks/period
at this API rate
Enter values above to see verdict

Calculation will appear here

Common provider reference prices

Spot-check before making decisions — providers change prices without notice. These are published list prices; volume discounts and committed-use rates vary.

Model / tierTypeInput ($/M tokens)Output ($/M tokens)Subscription ($/mo)
Claude Sonnet 4.x (API)Metered$3.00$15.00
Claude Opus 4.x (API)Metered$15.00$75.00
Claude Max (subscription)Subscription$100
Claude Max 20x (subscription)Subscription$200
GPT-4o (API)Metered$2.50$10.00
GPT-4o mini (API)Metered$0.15$0.60
OpenAI PlusSubscription$20
OpenAI ProSubscription$200
Gemini 2.5 Pro (API)Metered$1.25 (≤200k)$10.00
Gemini 2.0 Flash (API)Metered$0.10$0.40
The procurement question this calculator can't answer. Subscription efficiency depends heavily on whether your automation pattern is permitted by the provider's terms, whether you can observe remaining quota before it caps, and whether the model available on the subscription tier matches the one you'd buy metered. Measure all three before committing. See: Procurement teardown: claims-vs-evidence method →

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