Head-to-head comparison
R1 0528 (DeepSeek) and DeepSeek V3.1 Terminus (DeepSeek) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.
Snapshot as of 22 September 2026
As of 22 September 2026, R1 0528 holds the stronger ModelCap Index position (#62 vs #71); and DeepSeek V3.1 Terminus is 2.2× cheaper per output token ($1.00/1M vs $2.15/1M).
Evidence: 2 public benchmark observations across 2 boards · 3 public benchmark observations across 3 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.
Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.
Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.
R1 0528 ranks higher on the ModelCap Index as of 22 September 2026: #62 against #71. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.
DeepSeek V3.1 Terminus is cheaper on output tokens: $1.00/1M against $2.15/1M. Input tokens are $0.50/1M for R1 0528 and $0.27/1M for DeepSeek V3.1 Terminus. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $2.08 for R1 0528 versus $1.04 for DeepSeek V3.1 Terminus. DeepSeek V3.1 Terminus costs 49.9% less in this scenario. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.
Both publish a 164K-token context window.
Arena coding: R1 0528 1464, DeepSeek V3.1 Terminus 1461 — R1 0528 leads.
R1 0528: Open weights. DeepSeek V3.1 Terminus: Open weights. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.
ModelCap currently lists 4 API providers for R1 0528 and 4 for DeepSeek V3.1 Terminus, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.
Every figure comes from the sealed ModelCap dataset published 22 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.