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Kimi K2.6 vs Step 5 Preview

Close to a tie overall. Step 5 Preview costs 1% less for the same work.

Kimi K2.6

by Moonshot AI · #23 of 67 overall

Coming soon · price at launch
Context
256K
Input / 1M
$0.75
Output / 1M
$3.50

Step 5 Preview

by StepFun · #24 of 67 overall

Coming soon · price at launch
Context
1M
Input / 1M
$1.00
Output / 1M
$2.70

Better overall

About even

Grade 75.6 vs 75.2

Cheaper

Step 5 Preview

1% less, $1.43 vs $1.44 blended

Larger context

Step 5 Preview

256K vs 1M tokens

Head to head

Public benchmarks. Longer is better; each value links to its source.

LMArena TextElo-style rating · LMArena (CC BY 4.0) · Oct 28, 2026
LMArena WebDevElo-style rating · LMArena (CC BY 4.0) · Oct 13, 2026
LMArena CodingElo-style rating · LMArena (CC BY 4.0) · Oct 28, 2026
SWE-bench Verified% of issues resolved · SWE-bench · Apr 14, 2026 · reference
Step 5 PreviewStep 5 Preview: —
SWE-Bench Pro% of tasks resolved · Scale AI SWE-Bench Pro · Apr 14, 2026 · reference
Step 5 PreviewStep 5 Preview: —
Terminal-Bench 4.0% of tasks passed · Terminal-Bench · Sep 20, 2026 · reference
Kimi K2.6Kimi K2.6: —
Terminal-Bench 2.0% of tasks passed · Terminal-Bench · Apr 14, 2026 · reference
Step 5 PreviewStep 5 Preview: —
LiveCodeBenchpass@1, % · LiveCodeBench · Apr 14, 2026 · reference
Step 5 PreviewStep 5 Preview: —

Kimi K2.6Step 5 Previewv = reported by the model’s maker. — = no public score yet. Arena bars span the range across every model we grade.

What it costs you

Drag to match your monthly usage.

Kimi K2.6$290 /month
Step 5 Preview$308 /month

Kimi K2.6 saves you $18.00 a month at this usage, $216 a year.

At a glance

AttributeKimi K2.6Step 5 Preview
Made byMoonshot AIStepFun
AvailabilityComing soonComing soon
Overall gradeExcellent · 75.6Excellent · 75.2
Overall rank#23 of 67#24 of 67
Input price$0.75 per 1M$1.00 per 1M
Output price$3.50 per 1M$2.70 per 1M
Context window262,144 tokens1,048,576 tokens
Reasoning levelsNoNo
Reads imagesYesYes
Model IDkimi-k2.6step-5-preview

Try both with one key

Same endpoint, same key, both hosted in the USA. Change one word to switch models, in Claude Code, Cursor, Cline or your own code.

Get your API key
# Ask either model the same thing
curl https://fullsendai.com/v1/chat/completions \
  -H "Authorization: Bearer $FULLSEND_API_KEY" \
  -d '{"model": "kimi-k2.6", "messages": [...]}'

# …then swap one word
  -d '{"model": "step-5-preview", "messages": [...]}'

Questions

Is Kimi K2.6 or Step 5 Preview better?

They grade within two points of each other (75.6 and 75.2), so pick on price and the benchmarks that match your work.

Which is cheaper, Kimi K2.6 or Step 5 Preview?

Step 5 Preview: $1.00 in and $2.70 out per million tokens, against $0.75 and $3.50 through FullsendAI.

Which has the larger context window?

Step 5 Preview, with 1,048,576 tokens.

Can I use both with one API key?

Yes, once they launch: both are coming soon, at the prices shown, and both will use the same FullsendAI key.

Model rankingsAll benchmarksCompare other models

Scores: LMArena (CC BY 4.0), SWE-bench, Scale AI SWE-Bench Pro, Terminal-Bench, LiveCodeBench, and model makers’ published results where marked v. Prices are FullsendAI’s, per million tokens. Data as of Oct 28, 2026.