Head to head
ST vs For light moderate heavy
Verdict · measured basis
GPT-5 Nano costs $0.0010 per solved task against
Step 3.5 Flash at $0.0031 — ▼ 3.0x cheaper .
Over 200 tasks that is $0.41 a month.
On output token price alone Step 3.5 Flash looks 1.3x cheaper. The ranking reverses once you divide by pass rate — the cheaper tokens do not win the task.
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Verified pricing, pass rate and cost per solved task for Step 3.5 Flash and GPT-5 Nano Figure Step 3.5 Flash GPT-5 Nano Input $/Mtok $0.1 $0.05 Output $/Mtok $0.3 $0.4 Cached input $/Mtok $0.1 $0.005 Pass rate 50% 100% Cost per solved task $0.0031 measured $0.0010 measured Cost per month $0.62 $0.21
Cost per month against tasks per month · drag the marker
Monthly cost against tasks per month Log-log lines for GPT-5 Nano (measured, $0.0010 per solved task), Step 3.5 Flash (measured, $0.0031 per solved task) from 10 to 100,000 tasks a month. Marker at 200 tasks. 10 100 1k 10k 100k $0.01 $0.1 $1 $10 $100 TASKS / MONTH (log) → 200 tasks GPT-5 Nano · MEASURED · $0.0010 per solved task $0.21 GPT-5 Nano MEASURED Step 3.5 Flash · MEASURED · $0.0031 per solved task $0.62 Step 3.5 Flash MEASURED Monthly cost against tasks per month Log-log lines for GPT-5 Nano (measured, $0.0010 per solved task), Step 3.5 Flash (measured, $0.0031 per solved task) from 10 to 100,000 tasks a month. Marker at 200 tasks. 10 100 1k 10k 100k $0.01 $0.1 $1 $10 $100 TASKS / MONTH (log) → 200 tasks GPT-5 Nano · MEASURED · $0.0010 per solved task $0.21 Step 3.5 Flash · MEASURED · $0.0031 per solved task $0.62 — GPT-5 Nano · MEASURED — Step 3.5 Flash · MEASURED Solid measured · dashed modeled · dotted stale. The gap is the verdict.
Solvency Bench (solvency.dev) — first-party measurement · verified 2026-08-26 · prices from each provider's pricing page; measured rows ignore the tier · Methodology · All models at these settings