
LLM Inference: What AI Founders Should Know About Costs
Most founders notice the moment their billing dashboard stops looking like a rounding error. Usage climbs, artificial intelligence (AI) API calls stack up and the gap between projected and actual burn widens faster than the revenue line. Large language model (LLM) inference costs drive that gap, and getting a handle on them changes how you build, price and scale your product.
This article covers the current pricing environment, the cost strategies that move the needle fastest and when to consider owning your own infrastructure.
The Pricing Environment Is Shifting Fast
Model pricing has dropped quickly over the past 12 to 18 months, and founders who priced their products around earlier rate cards may find their cost assumptions outdated by the time they reach Series A conversations.
Where Rates Stand in Mid-2026
Budget tier models now cost as little as $0.075 per million input tokens. Gemini API pricing shows Google models at that low end. Mid-tier options like Claude Haiku 4.5 and Gemini 2.5 Pro deliver stronger reasoning at moderate cost. Flagship models from Anthropic and OpenAI run at meaningfully higher rates, with output priced noticeably above input.
The Deflation Trend
Inference costs for equivalent performance have fallen fast. Mistral Large input pricing has dropped from $3.00 per million tokens to $2.00 per million tokens. OpenAI cut o3 pricing by 80 percent in a single announcement, moving from $10.00 to $2.00 per million input tokens. Anthropic's own Opus line also saw a sizable reduction between releases 4.1 and 4.8. Models that feel expensive today may cost a fraction of their current price by the time you're raising your next round.
Why Output Tokens Drive Up Your Bill
Every inference call has two phases, and they cost sharply different amounts. The split matters for how you architect your product and estimate your cost of goods sold (COGS). Most surprise bills trace back to output pricing, where providers charge materially more for generated tokens than for input tokens.
The Input vs. Output Asymmetry
Output tokens cost materially more than input tokens across major providers. GPT-4.1 and Claude Sonnet 4.6 both follow that pattern, with output priced above input. Input processing runs in parallel at high compute efficiency, while output generation produces one token at a time in a sequential, memory-bandwidth-bound process. Your product's output-to-input ratio determines more about your inference bill than which model you choose.
Context Windows and Hidden Memory Costs
Longer context windows increase costs through two mechanisms: the direct token count and the graphics processing unit (GPU) memory required to hold the key-value (KV) cache. When context length pushes past a single GPU's memory capacity, deployment often moves to multi-GPU setups, which can increase hourly costs significantly rather than scaling smoothly. Agentic workflows make this worse because the number of input tokens grows with each conversation turn. Turn 30 of a multi-step agent costs more than turn one for the same user-visible task.
Cutting Inference Costs at Early Stage
CRV, an early stage venture capital firm focused on leading seed and Series A rounds, sees AI founders consistently underestimate how much control they have over inference economics. We ordered the strategies below by implementation effort, starting with the fastest wins. Startups operating at seed and Series A scale have tested each technique listed here.
Prompt Caching
Prompt caching reuses previously computed results for repeated prompt prefixes, and the savings can be significant, depending on the provider. Cache reads run far cheaper than standard input rates: OpenAI applies automatic prefix caching on GPT-4o and newer models at a 50 percent discount and Google offers similar reductions across the Gemini 2.5 line, with discounts varying by caching mode.
One detail trips up many teams: dynamic content placed before static context blocks breaks cache reuse entirely, so your system prompt and any shared retrieval-augmented generation (RAG) context need to come first, with per-request content appended after. A well-structured caching setup for a 3,500-token system prompt can meaningfully reduce costs for that cached portion, which adds up quickly at scale.
Model Routing and Cascading
Model routing sends simple queries to cheap models and escalates to expensive ones only when needed. Teams using model routing have cut costs, showing large cost reductions for mixed-complexity workloads, and approaches that route only a minority of queries to larger models can meaningfully reduce costs. A customer support product handling both "what are your pricing plans" and "why is my integration throwing errors" can route the first query to a $0.10 model and reserve the $3.00 model for the second. CRV-backed CodeRabbit's AI code review, which runs at scale, operates in exactly this kind of mixed-complexity environment where routing decisions directly affect unit economics.
Batch Processing
Batch API endpoints carry roughly a 50 percent discount compared with synchronous calls, and providers designed them for asynchronous, non-real-time workloads. Three categories of jobs move well to batch endpoints:
- Document processing pipelines: Ingestion and extraction jobs that don't need immediate responses can run overnight at the lower rate with no product impact.
- Embedding and index updates: RAG index refreshes and nightly embedding runs are natural fits and require minimal code changes to redirect from synchronous endpoints.
- Evaluation runs: Model evaluation jobs, which often consume large volumes of tokens, can run at batch rates without affecting production latency.
Switching eligible jobs to batch endpoints often requires relatively little engineering effort. Even partial migration of background jobs can produce meaningful savings in the first billing cycle.
Build or Buy for Inference Infrastructure
The right position on the spectrum from frontier APIs through managed open-weight providers to full self-hosting depends on your token volume, team size and data requirements. Founders often move along that spectrum as those requirements change.
When Managed APIs Make Sense
Most seed stage founders should default to managed APIs. We use Runpod GPU pricing to estimate breakeven for self-hosting against OpenAI's GPT-4.1 pricing on compute costs alone, before accounting for engineering time. Against managed open-weight providers like Together AI, that breakeven climbs higher, to well over a billion tokens per month on a single H100. A team of two to five engineers burning cycles on GPU infrastructure management rather than on product development incurs an opportunity cost that rarely shows up in a build-versus-buy spreadsheet.
When Self-Hosting Pays Off
Self-hosting starts making financial sense when token volumes consistently exceed the breakeven thresholds above, when proprietary fine-tuned weights can't run through third-party APIs or when regulatory requirements (healthcare, finance and legal) mandate keeping prompts on-premises.
With quantization, you can reduce model precision from 16-bit to four-bit and shrink memory requirements, with some benchmarks showing inference cost reductions of more than 60 percent while fitting the model onto cheaper GPUs. Cloud providers can preempt spot instances mid-inference, reserved instances lock you into long-term capacity commitments at today's prices in a market where costs keep declining, and bursty traffic patterns can leave expensive hardware sitting idle much of the time.
Gross Margins and What Investors Expect
AI gross margins tend to run lower than traditional software-as-a-service (SaaS) benchmarks, and most investors evaluating your company know that. Traditional SaaS products approach near-zero marginal cost per user once the software ships. With AI products, every customer interaction incurs a direct inference expense that generally increases with usage, though the cost varies by request type and system design.
AI startups can report lower gross margins than their traditional SaaS peers due to compute costs. AI-native startups founded after 2022 also run below that SaaS peer benchmark. We've written before about how AI companies get extra scrutiny on burn multiple because variable inference costs can inflate what looks like software revenue.
Directional improvement across margin metrics often carries more weight at early stages than hitting a specific benchmark. A 50 to 60 percent gross margin is defensible today if you can articulate a clear path toward expansion through model routing, distillation or changes to the pricing structure.
Treating Every Model Call as a Cost Line
Founders who treat inference economics as a product design decision, rather than a back-office concern, tend to build better cost structures from the start. We've seen the strongest outcomes from teams that wire cost awareness into their architecture early, before a surprise bill forces the conversation. Treating every model call as a line item in your cost of goods sold is a habit that pays off more at each funding stage.
If you're an early stage founder looking for a partner who understands the unit economics of AI products, reach out to us to see if we'd be a good fit.
Frequently Asked Questions About LLM Inference Costs
How fast are LLM inference costs declining?
Inference costs for equivalent performance have dropped fast, and some individual model lines have moved even further. OpenAI's o3 fell 80 percent in a single pricing update, and Mistral Large dropped from around $3.00 to $2.00 per million input tokens since mid-2024. Founders should avoid locking into long-term infrastructure commitments at current rates and instead plan for flexibility.
What gross margin should an AI startup target at seed stage?
Many seed stage AI companies land below the broader AI startup benchmark, especially at the application layer. Investors have recalibrated their expectations from the 70 to 90 percent SaaS benchmark, but they want to see a documented plan for margin expansion. Showing quarter-over-quarter improvement, even by a few points, demonstrates that you understand your cost structure and know which changes will expand margins.
When should an AI startup consider self-hosting models?
Self-hosting can start to make financial sense at high token volumes, but the breakeven point varies widely by model, hardware and API pricing. Data privacy requirements in regulated industries (healthcare, finance and legal) can also force the decision earlier. Most seed stage teams benefit from starting with managed APIs and transitioning to self-hosting only after reaching sustained volume thresholds and having the engineering capacity to manage infrastructure.
How can a small engineering team reduce inference costs quickly?
Prompt caching and batch processing offer the highest return for the least engineering effort. Enabling prompt caching can save up to 90 percent on cached input portions. Moving non-real-time workloads to batch endpoints can reduce costs by up to 50 percent with minimal code changes. Model routing adds more complexity, but can still cut costs meaningfully on mixed-complexity workloads.