Last verified 2025-09-22 (left) · 2026-03-12 (right)

Claude Sonnet 3.7 (Legacy) vs DeepSeek Chat — Pricing & Capability Comparison

Claude Sonnet 3.7 (Legacy) charges $3.00 per million input tokens and $15.00 per million output tokens. DeepSeek Chat comes in at $0.27 / $1.10. Context windows span 200K vs 64K tokens respectively.

TL;DR — Quick Comparison

✓DeepSeek Chat is cheaper overall: $1.37 per 1M tokens (in+out) vs $18.00 for Claude Sonnet 3.7 (Legacy) — saves $16.63 per 1M tokens
✓Input pricing: Claude Sonnet 3.7 (Legacy) $3.00/1M vs DeepSeek Chat $0.27/1M
✓Output pricing: Claude Sonnet 3.7 (Legacy) $15.00/1M vs DeepSeek Chat $1.10/1M
✓Context window: Claude Sonnet 3.7 (Legacy) offers more (200K vs 64K)
✓Use our calculator below to estimate costs for your specific usage pattern

Input price (per 1M)

Claude Sonnet 3.7 (Legacy)

$3.00

DeepSeek Chat

$0.27

DeepSeek Chat leads here

Output price (per 1M)

Claude Sonnet 3.7 (Legacy)

$15.00

DeepSeek Chat

$1.10

DeepSeek Chat leads here

Context window

Claude Sonnet 3.7 (Legacy)

200,000 tokens

DeepSeek Chat

64,000 tokens

Claude Sonnet 3.7 (Legacy) leads here

Cached input

Claude Sonnet 3.7 (Legacy)

Not published

DeepSeek Chat

$0.070

DeepSeek Chat leads here

Which one should you choose?

Skip the spreadsheet if you just need the practical takeaway. Use these rules when deciding between Claude Sonnet 3.7 (Legacy) and DeepSeek Chat.

Choose DeepSeek Chat if input tokens dominate your bill

DeepSeek Chat has the lower input rate, which usually matters most for chat, RAG, classification, and long-prompt workflows where prompt volume stays much larger than generated output.

Choose DeepSeek Chat if you generate long answers

DeepSeek Chat is cheaper on output tokens, so it tends to win for report generation, coding assistance, reasoning traces, and any workflow where completions are long.

Choose Claude Sonnet 3.7 (Legacy) if context size is the blocker

Claude Sonnet 3.7 (Legacy) offers the larger published context window, which is more important than small pricing differences when you need to fit large files, long chats, or multi-document prompts into one request.

Cost comparison for 10K-token workloads

Side-by-side pricing for identical workloads (10,000 total tokens per request) across different distributions.

Scenario	Claude Sonnet 3.7 (Legacy)	DeepSeek Chat	DeepSeek Chat cached
Balanced conversation 50% input · 50% output	$0.0900	$0.0069	$0.0059
Input-heavy workflow 80% input · 20% output	$0.0540	$0.0044	$0.0028
Generation heavy 30% input · 70% output	$0.114	$0.0085	$0.0079
Cached system prompt 90% cached input · 10% fresh output	$0.0420	$0.0035	$0.0017

Frequently asked questions

Which is cheaper: Claude Sonnet 3.7 (Legacy) or DeepSeek Chat?

DeepSeek Chat is cheaper for input tokens at $0.27 per 1M tokens compared to $3.00. For output, DeepSeek Chat costs $1.10 per 1M tokens versus $15.00 for Claude Sonnet 3.7 (Legacy).

What is the cost per 1M tokens for Claude Sonnet 3.7 (Legacy)?

Claude Sonnet 3.7 (Legacy) pricing: $3.00 per 1M input tokens and $15.00 per 1M output tokens. Context window: 200,000 tokens.

What is the cost per 1M tokens for DeepSeek Chat?

DeepSeek Chat pricing: $0.27 per 1M input tokens and $1.10 per 1M output tokens. Context window: 64,000 tokens.

How much does it cost per 1K tokens?

Per 1K tokens: Claude Sonnet 3.7 (Legacy) costs $0.0030 input / $0.0150 output. DeepSeek Chat costs $0.0003 input / $0.0011 output. This is useful for calculating small-scale usage costs.

Which model supports a larger context window?

Claude Sonnet 3.7 (Legacy) offers 200,000 tokens (200K) versus 64K for DeepSeek Chat.

What is the estimated monthly cost for typical usage?

For a typical workload of 10M input + 2M output tokens per month: Claude Sonnet 3.7 (Legacy) would cost approximately $60.00, while DeepSeek Chat would cost $4.90. DeepSeek Chat is more economical for this usage pattern.

Do these models support prompt caching?

Claude Sonnet 3.7 (Legacy) does not publish cached pricing. DeepSeek Chat supports caching at $0.070 per 1M tokens, saving up to 74%.

Which model is best for my use case?

Choose DeepSeek Chat for cost-sensitive applications with high input volume. Choose Claude Sonnet 3.7 (Legacy) if you need 200K context for long documents or conversations. Consider prompt caching if you have repeated context. Use our token calculator to model your specific usage pattern.