API cost decision in 10 seconds

Step 3.5 Flash vs Rnj 1 Instruct

Pick Rnj 1 Instruct for lower cost; pick Step 3.5 Flash only if the larger context window matters more.

Page updated: 2026-05-26T10:03:26Z Data confirmed: 2026-05-26T13:08:02Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Rnj 1 Instruct for lower cost; pick Step 3.5 Flash only if the larger context window matters more.

On the standard 1M input plus 500K output workload, Rnj 1 Instruct is estimated at $0.22 vs $0.24 for Step 3.5 Flash, saving $0.02 (6.3% lower).

Cost-first pickRnj 1 Instruct

Context-first pickStep 3.5 Flash

Sample savings$0.026.3%

10x traffic gap$0.15

Step 3.5 Flash has more context, but Rnj 1 Instruct saves $0.02 on the standard workload. At 10x that traffic, the same price gap is about $0.15. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Cost winner changes by workload shape: input-heavy / RAG favors Step 3.5 Flash, balanced workload favors Rnj 1 Instruct, and output-heavy chatbot favors Rnj 1 Instruct.

Workload shape	Token mix	Better pick	Step 3.5 Flash	Rnj 1 Instruct
Input-heavy / RAG	5M input + 500K output	Step 3.5 Flash	$0.6	$0.82
Balanced workload	1M input + 1M output	Rnj 1 Instruct	$0.39	$0.3
Output-heavy chatbot	1M input + 5M output	Rnj 1 Instruct	$1.59	$0.9

Cheaper input Step 3.5 Flash $0.09 vs $0.15 / 1M

Step 3.5 Flash is $0.06 cheaper per 1M input tokens (40% lower; 1.67x difference).

Cheaper output Rnj 1 Instruct $0.3 vs $0.15 / 1M

Rnj 1 Instruct is $0.15 cheaper per 1M output tokens (50% lower; 2x difference).

Larger context Step 3.5 Flash 262.14K vs 32.77K

Step 3.5 Flash has 229.38K more context (8x larger).

Sample workload Rnj 1 Instruct $0.24 vs $0.22

Rnj 1 Instruct is $0.02 cheaper on the standard workload (6.3% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

Step 3.5 Flash Calculating… Estimated API cost

Rnj 1 Instruct Calculating… Estimated API cost

Cheaper for this workload Calculating… Difference: calculating…

This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.

Quick Decision

Verdict

Step 3.5 Flash has the lower input price; Rnj 1 Instruct has the lower output price; Step 3.5 Flash offers the larger context window. For the 1M input plus 500K output sample, Rnj 1 Instruct is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $0.24 for Step 3.5 Flash and $0.22 for Rnj 1 Instruct.

Best Fit

Choose Step 3.5 Flash when you care most about lower input-token price, and larger context window.

Choose Rnj 1 Instruct when you care most about lower output-token price.

Decision Notes

On the standard 1M input plus 500K output workload, Rnj 1 Instruct is estimated at $0.22 vs $0.24 for Step 3.5 Flash, saving $0.02 (6.3% lower).
Rnj 1 Instruct is $0.02 cheaper on the standard workload (6.3% lower).
Step 3.5 Flash is $0.06 cheaper per 1M input tokens (40% lower; 1.67x difference).
Rnj 1 Instruct is $0.15 cheaper per 1M output tokens (50% lower; 2x difference).
Step 3.5 Flash has 229.38K more context (8x larger).

Head-to-Head Specs

Feature	Step 3.5 Flash (StepFun)	Rnj 1 Instruct (EssentialAI)
Input Price prompt tokens per 1M	$0.09	$0.15
Completion Price per 1M tokens	$0.3	$0.15
Sample Workload Cost 1M input + 500K output	$0.24	$0.22
Context Window	262.14K	32.77K
Release Date	2026-01-29	2025-12-07

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	Rnj 1 Instruct	On the standard 1M input plus 500K output workload, Rnj 1 Instruct is estimated at $0.22 vs $0.24 for Step 3.5 Flash, saving $0.02 (6.3% lower).
High-volume input processing	Step 3.5 Flash	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	Rnj 1 Instruct	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	Step 3.5 Flash	A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps

No lower-cost same-provider swap is currently tracked for this pair.

Larger context near this budget

Llama 4 Scout offers 10M context with $0.23 sample workload cost.
Owl Alpha offers 1.05M context with $0 sample workload cost.
DeepSeek V4 Flash offers 1.05M context with $0.2 sample workload cost.
DeepSeek V4 Flash (free) offers 1.05M context with $0 sample workload cost.

Popular competitors

DeepSeek V4 Flash · DeepSeek · #1
Hy3 preview · Tencent · #2
Claude Opus 4.7 · Anthropic · #3
Claude Sonnet 4.6 · Anthropic · #4

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Provider catalogs

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StepFun catalog

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EssentialAI catalog

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Step 3.5 Flash

Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parameters per token....

Rnj 1 Instruct

Rnj-1 is an 8B-parameter, dense, open-weight model family developed by Essential AI and trained from scratch with a focus on programming, math, and scientific reasoning. The model demonstrates strong performance...