PROMPT CACHE ECONOMICS
Subscription vs Metered API Cost Calculator
Autonomous coding agents re-read tens of millions of context tokens per build. Factor in cache-hit ratio to find the exact breakeven between $20–$200 flat plans and metered API spend.
1. Pick a Bench Preset or Tune Workload
Heavy Agent Runs per Day
2 / day
Total Context Read per Run (M Tokens)
22 M
Prompt Cache Hit Ratio
92%
Output per Run (K Tokens)
110 K
Monthly Subscription Benchmark
$200 / mo
2. Projected Monthly Spend & Breakeven
| Model Tier | Est. / Run | Est. / 30 Days | vs Flat Plan |
|---|
| Task | Models & Elapsed Time | Token / Quality Log | Recorded Spend |
|---|---|---|---|
| Q06 · Dynamic Island 12s | Opus 5.5 (33m) / Hydrogen (17m) / Carbon (24m) | SSIM 0.9559 / 0.9133 / 0.9325 | $9.23 / $2.45 / $1.94 (50% promo) |
| Q05 · 3D Rube Tower | Carbon (58m) / Opus 5.5 (43m) / Argon (35m) | 6 collision audit passes · 640×1080 Three.js | $4.81 / $9.12 / $2.51 |
| R01 · Pixel 3D Basketball | DeepSeek V4.1 Flash (1h41m) vs Sonnet 5.5 | 944K + 120.68M Cache + 659K Out (99.2% hit) | ~$0.90 (off-peak) / ~$1.80 vs $48.31 |