DeepSeek V4.1 Flash vs Gemini 3.1 Flash Lite Cost
DeepSeek V4.1 Flash or Gemini 3.1 Flash Lite? Spec sheets compare headlines; this page prices your actual workload — and shows the output ratio where the answer flips.
For engineers choosing between two models — compares real bills at your workload (output skew + caching included) and shows where the answer flips, not a spec sheet.
Model prices from OpenRouter · updated 2026-09-16
01 Your matchup & workload
02 At your workload
DeepSeek V4.1 Flash wins by $50.32/month (58%) here.
No flip at this input size — DeepSeek V4.1 Flash wins at every output length.
Related cost calculators
Prices from OpenRouter, snapshot 2026-09-16, synced daily. Each model billed at your workload with its own cache-read pricing on the cached share; flip point solves input × (effInA − effInB) + output × (outA − outB) = 0. Cost is a shortlist — quality on your evals decides. All math runs in your browser.
How the math works
Spec-sheet comparisons list prices; this page prices a workload. At the defaults — 1,000 input + 500 output tokens per request, 100,000 requests a month, 60% cached prefix — DeepSeek V4.1 Flash bills $36.18/month against Gemini 3.1 Flash Lite's $86.50: 58% apart.
DeepSeek V4.1 Flash lists $0.15/M in and $0.6/M out (cache reads $0.003/M); Gemini 3.1 Flash Lite lists $0.25/M and $1.5/M (reads $0.025/M). Headlines don't settle it — the blend of your input/output mix and each model's caching does.
At this input size the answer never flips: one model is cheaper at every output length, so the choice is about quality and context window, not the output ratio.
Cost is the shortlist, not the verdict: context windows (DeepSeek V4.1 Flash: 1049K vs Gemini 3.1 Flash Lite: 1049K), caching support, and quality on your evals decide the rest. Prices sync daily from OpenRouter; all math runs in your browser.
Frequently asked questions
Which is cheaper, DeepSeek V4.1 Flash or Gemini 3.1 Flash Lite?
At this page's default workload, DeepSeek V4.1 Flash: $36.18/month vs $86.50 — 58% less. But the gap depends on your input/output mix. Tune the sliders above for your real shape.
Why not just compare the advertised prices?
Because they're input rates. DeepSeek V4.1 Flash charges $0.6/M for output and Gemini 3.1 Flash Lite $1.5/M — and output typically drives 60–85% of a bill. Add caching ($0.003/M vs $0.025/M reads) and two same-headline models can differ 2–3× on a real workload.
When does the cheaper model flip?
At this input size, never — one model wins at every output length. The flip only exists when one model has cheaper effective input and the other cheaper output.
Is the cheaper model the right choice?
Only if quality holds on your task. Use this page to quantify the price of preference: if Gemini 3.1 Flash Lite wins your evals, the premium is $50.32/month at these defaults — sometimes that's obviously worth it, sometimes obviously not. Context windows and caching support (both shown above) can also decide it outright.
Are these prices current?
Prices sync daily from OpenRouter's public catalog and the page shows its snapshot date. If a sync fails, the last verified snapshot keeps serving. All math runs client-side with tested code.