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AI investment & economics

Inference run-rate forecaster

Inspect each month of API and self-host cost before making a platform commitment.

Current decision

No monthly crossover in 24 months

24-month total: API $686k; self-host $3.22M. A monthly crossover does not by itself recover earlier spend.
Pin a month below, then test utilization and volume. Prices are explicit illustrative assumptions, not current vendor quotes.

Same instrument · 3 industries choosing a scenario replaces its inputs; save or share your current changes first

0.5M/mo
6%
3,000
40%
60%
1.5

Monthly run rate · 24 months

API Self host
mo 1mo 12mo 24$185k
Month 1
Month 1: API $14k; self-host $71k. API is lower by $58k for this month.
All 24 monthly values
All 24 monthly values
MonthAPI (USD/month)Self-host (USD/month)Lower monthly cost
113,50071,000API
214,310109,000API
315,169109,000API
416,079109,000API
517,043109,000API
618,066109,000API
719,150109,000API
820,299109,000API
921,517109,000API
1022,808109,000API
1124,176109,000API
1225,627109,000API
1327,165147,000API
1428,795147,000API
1530,522147,000API
1632,354147,000API
1734,295147,000API
1836,352147,000API
1938,534147,000API
2040,846185,000API
2143,296185,000API
2245,894185,000API
2348,648185,000API
2451,567185,000API
The cliff
N/A

Beyond 24 mo

API · 24-mo total
$686k

Cumulative

Self host · 24 mo total
$3.22M

Cumulative

Crossover sensitivity · crossover under each single move

  • Growth → 12%/mono cliff
  • Frontier share → 20%no cliff
  • Tokens/call → 4,500no cliff
  • Utilization → 85%no cliff

Each row recomputes the crossover with one assumption changed, earlier (green) means self-host monthly cost first undercuts API sooner; cumulative payback may differ.

No cliff inside 24 months

At these assumptions API stays cheaper for all 24 months. Inspect volume, model mix and utilization independently; each can change the relative economics.

If you act on this · the call → expected lift → how you'd measure it

The call

Revisit inference strategy when volume and utilization make the run rate materially different from the pilot economics.

Expected lift · illustrative

Avoids both premature self hosting and uncontrolled API spend.

How you'd measure it

Monthly run rate, cumulative 24 month cost, utilization, cost per task, crossover month.

Steering committee takeaway: The crossover is not decided by vendor claims. It is decided by utilization, growth, and the share of workloads that truly need higher cost models.

How this is built & assumptions

API/mo = volume × tokens/call × blended price ($3 to $18/1M tokens by frontier share). Volume compounds at the monthly growth rate.

Self host/mo = ⌈tokens ÷ (cluster capacity 2.5B × utilization)⌉ × $38k amortized + ops FTE × $22k. The cliff is the first month self-host < API.

Stack: Next.js (static) + shared design system; deterministic client side.

Limitations: this model uses simplified cost assumptions. Production forecasting would require current pricing, workload profiles, infrastructure benchmarks, reliability requirements, and finance approved cost allocation.

Method, evidence and limitations
Prefer to read? The two minute case study · problem → approach → metric → outcome

Problem

API usage offers flexibility, but cost scales with volume. Self hosting can reduce marginal cost after utilization reaches the right level, but it introduces fixed capacity, operations, infrastructure, and talent requirements, and the decision depends on utilization more than sticker price.

Approach

The forecaster projects API and self hosted costs across 24 months. It marks the crossover point and shows how growth, token volume, frontier model share, utilization, and staffing assumptions move the decision.

Why this way

This connects AI operating strategy to budget planning, unit economics, platform investment, infrastructure commitments, and cost governance.

The metric

The crossover month; 24-month cumulative cost each way.

The trade-off

API is flexible pay per use; self host is fixed capacity that only amortizes past the crossover.

Outcome

The crossover month with the assumption that moves it most made explicit.