Greenbyte Insights · Evidence Lab

GPT-5.6 cost vs performance

Nine benchmark families, 192 traceable points and references, and one important warning: token-price changes do not automatically equal task-cost changes.

Published · August 26, 2026Official pricing reverified · August 26, 2026

Method.

Scores never change. Current mode applies Luna ×0.2 and Terra ×0.8 to recoverable launch coordinates, plus Sol ×0.8 PROJECTED from its input-rate reduction. Sol output fell 33.3%, and benchmark token/tool mixes are unpublished, so this is a conservative visual estimate—not an exact benchmark invoice.

Source scores unchanged

9 / 192

9 benchmarks · 192 points / references

Current API rates

Input / cached input / output · USD per 1M text tokens

Sol promotional rates: $4 / $0.40 / $20 · available at least through November 21, 2026.

GPT-5.6 Luna

$0.2 / $0.020 / $1.2

80% ↓ input

GPT-5.6 Terra

$2.0 / $0.2 / $12.0

20% ↓ input

GPT-5.6 Sol

$4.0 / $0.4 / $20.0

20% ↓ input

9 benchmarks · 192 points / references

Source scores unchanged

Pricing

X-axis

Agents’ Last Exam

Score (%) vs estimated API cost · Aug 21 current estimate

DigitizedSol ×0.8 · PROJECTED

1.0×

Terra and Luna use July 30 adjusted pricing. Because OpenAI says cost simulations may include tool-call charges, adjusted total cost is labeled estimated.

PROJECTED from current token pricing; exact task cost depends on token and tool mix

GPT-5.6 SolGPT-5.6 TerraGPT-5.6 LunaGPT-5.5Claude Opus 4.8Claude Fable 5Gemini 3.1 Pro

View accessible data

Model	Effort	Estimated cost	Score	Source quality
GPT-5.6 Sol	P1	$98.4 · PROJECTED	37.5%	Digitized
GPT-5.6 Sol	P2	$188 · PROJECTED	44.8%	Digitized
GPT-5.6 Sol	P3	$341 · PROJECTED	49.3%	Digitized
GPT-5.6 Sol	P4	$446 · PROJECTED	52.1%	Digitized
GPT-5.6 Sol	P5	$602 · PROJECTED	53.6%	Digitized
GPT-5.6 Sol	Max	$855 · PROJECTED	52.7%	Digitized
GPT-5.6 Terra	P1	$64.0	40.3%	Digitized
GPT-5.6 Terra	P2	$94.4	42.6%	Digitized
GPT-5.6 Terra	P3	$202	46.3%	Digitized
GPT-5.6 Terra	P4	$293	48.5%	Digitized
GPT-5.6 Terra	Max	$420	50.4%	Digitized
GPT-5.6 Luna	P1	$2.4	30.8%	Digitized
GPT-5.6 Luna	P2	$9.2	36.2%	Digitized
GPT-5.6 Luna	P3	$25.8	45.4%	Digitized
GPT-5.6 Luna	P4	$47.4	48.6%	Digitized
GPT-5.6 Luna	Max	$81.4	50.3%	Digitized
GPT-5.5	P1	$124	37.5%	Digitized
GPT-5.5	P2	$280	41.3%	Digitized
GPT-5.5	P3	$372	44.9%	Digitized
GPT-5.5	XHigh	$585	46.9%	Digitized
Claude Opus 4.8	P1	$1,168	37.5%	Digitized
Claude Opus 4.8	P2	$1,700	38.8%	Digitized
Claude Opus 4.8	P3	$2,800	42.2%	Digitized
Claude Opus 4.8	Max	$4,000	45.2%	Digitized
Claude Fable 5	Max	$2,300	40.5%	Digitized
Gemini 3.1 Pro	Preview	$2,000	32.1%	Digitized

Artificial Analysis Intelligence Index v4.1

Index score vs estimated API cost · Aug 21 current estimate

DigitizedSol ×0.8 · PROJECTED

1.0×

Launch chart coordinates are preserved; Terra ×0.8 and Luna ×0.2 in adjusted-price view.

PROJECTED from current token pricing; exact task cost depends on token and tool mix

GPT-5.6 SolGPT-5.6 TerraGPT-5.6 LunaGPT-5.5Claude Fable 5Claude Opus 4.8Gemini 3.5 FlashGemini 3.1 Pro

View accessible data

Model	Effort	Estimated cost	Score	Source quality
GPT-5.6 Sol	P1	$194 · PROJECTED	41.2	Digitized
GPT-5.6 Sol	P2	$286 · PROJECTED	49.5	Digitized
GPT-5.6 Sol	P3	$480 · PROJECTED	53.6	Digitized
GPT-5.6 Sol	P4	$777 · PROJECTED	55.9	Digitized
GPT-5.6 Sol	P5	$1,246 · PROJECTED	57.8	Digitized
GPT-5.6 Sol	Max	$2,274 · PROJECTED	58.9	Digitized
GPT-5.6 Terra	P1	$103	34.1	Digitized
GPT-5.6 Terra	P2	$126	40.5	Digitized
GPT-5.6 Terra	P3	$194	45.7	Digitized
GPT-5.6 Terra	P4	$389	49	Digitized
GPT-5.6 Terra	P5	$594	51.7	Digitized
GPT-5.6 Terra	Max	$1,417	55	Digitized
GPT-5.6 Luna	P1	$8.58	26.7	Digitized
GPT-5.6 Luna	P2	$14.3	33.3	Digitized
GPT-5.6 Luna	P3	$20.0	38.1	Digitized
GPT-5.6 Luna	Max	$174	51.2	Digitized
GPT-5.5	P1	$186	35.5	Digitized
GPT-5.5	P2	$357	43.6	Digitized
GPT-5.5	P3	$871	50.5	Digitized
GPT-5.5	P4	$1,657	53.3	Digitized
GPT-5.5	XHigh	$2,643	54.8	Digitized
Claude Fable 5	Max	$5,639	59.9	Digitized
Claude Opus 4.8	Max	$3,760	55.7	Digitized
Gemini 3.5 Flash	Not specified	$1,038	50.2	Digitized
Gemini 3.1 Pro	Preview	$811	46.5	Digitized

Artificial Analysis Coding Agent Index v1.1

Index score vs estimated API cost · Aug 21 current estimate

DigitizedSol ×0.8 · PROJECTED

1.0×

Includes the recovered reasoning-effort points for GPT-5.6 variants, GPT-5.5 and competitors.

PROJECTED from current token pricing; exact task cost depends on token and tool mix

GPT-5.6 SolGPT-5.6 TerraGPT-5.6 LunaGPT-5.5Claude Opus 4.8Claude Fable 5Gemini 3.1 Pro

View accessible data

Model	Effort	Estimated cost	Score	Source quality
GPT-5.6 Sol	P1	$396 · PROJECTED	57.3	Digitized
GPT-5.6 Sol	P2	$499 · PROJECTED	68.3	Digitized
GPT-5.6 Sol	P3	$857 · PROJECTED	73.7	Digitized
GPT-5.6 Sol	P4	$1,182 · PROJECTED	76.4	Digitized
GPT-5.6 Sol	P5	$1,492 · PROJECTED	78.1	Digitized
GPT-5.6 Sol	Max	$2,018 · PROJECTED	80	Digitized
GPT-5.6 Terra	P1	$114	38.6	Digitized
GPT-5.6 Terra	P2	$146	52.5	Digitized
GPT-5.6 Terra	P3	$260	63.2	Digitized
GPT-5.6 Terra	P4	$456	71	Digitized
GPT-5.6 Terra	P5	$537	72.4	Digitized
GPT-5.6 Terra	Max	$776	77.4	Digitized
GPT-5.6 Luna	P1	$27.1	35.6	Digitized
GPT-5.6 Luna	P2	$17.6	40.8	Digitized
GPT-5.6 Luna	P3	$35.3	57.6	Digitized
GPT-5.6 Luna	P4	$69.2	66.9	Digitized
GPT-5.6 Luna	P5	$90.8	69.8	Digitized
GPT-5.6 Luna	Max	$111	74.6	Digitized
GPT-5.5	P1	$346	44.1	Digitized
GPT-5.5	P2	$420	56.6	Digitized
GPT-5.5	P3	$963	69.7	Digitized
GPT-5.5	P4	$970	71.7	Digitized
GPT-5.5	XHigh	$1,763	76.4	Digitized
Claude Opus 4.8	P1	$1,080	67	Digitized
Claude Opus 4.8	Max	$2,534	72.5	Digitized
Claude Fable 5	Max	$3,864	77.2	Digitized
Gemini 3.1 Pro	Preview	$664	42.7	Digitized

Terminal-Bench 2.1

Score (%) vs estimated API cost · Aug 21 current estimate

Mixed evidenceSol ×0.8 · PROJECTED

1.0×

Cost curve is shown where a defensible launch x-coordinate was recoverable. Other official scores are shown as horizontal references rather than inventing costs.

PROJECTED from current token pricing; exact task cost depends on token and tool mix

GPT-5.6 SolGPT-5.6 Sol UltraGPT-5.5GPT-5.6 TerraGPT-5.6 LunaClaude Mythos 5Claude Fable 5Claude Opus 4.8Gemini 3.1 Pro

View accessible data

Model	Effort	Estimated cost	Score	Source quality
GPT-5.6 Sol	Low	$0.496 · PROJECTED	76%	Digitized
GPT-5.6 Sol	Medium	$0.672 · PROJECTED	80%	Digitized
GPT-5.6 Sol	High	$0.84 · PROJECTED	84%	Digitized
GPT-5.6 Sol	XHigh	$1.02 · PROJECTED	86.5%	Digitized
GPT-5.6 Sol	Max	$1.36 · PROJECTED	88.8%	Digitized
GPT-5.6 Sol Ultra	Ultra	$4.16 · PROJECTED	91.9%	Digitized
GPT-5.5	Low	$0.35	73%	Digitized
GPT-5.5	Medium	$0.55	78%	Digitized
GPT-5.5	High	$1.15	83%	Digitized
GPT-5.5	XHigh	$2.2	85.6%	Digitized
GPT-5.6 Terra	Not specified	Score only — no cost invented	87.4%	Official reference
GPT-5.6 Luna	Not specified	Score only — no cost invented	84.7%	Official reference
Claude Mythos 5	Not specified	Score only — no cost invented	88%	Official reference
Claude Fable 5	Not specified	Score only — no cost invented	83.1%	Official reference
Claude Opus 4.8	Not specified	Score only — no cost invented	78.9%	Official reference
Gemini 3.1 Pro	Not specified	Score only — no cost invented	70.7%	Official reference

DeepSWE v1.1

Score (%) vs estimated API cost · Aug 21 current estimate

ExactSol ×0.8 · PROJECTED

1.0×

This benchmark has the cleanest price update because the canonical leaderboard recorded the July 30 pricing change.

PROJECTED from current token pricing; exact task cost depends on token and tool mix

GPT-5.6 SolGPT-5.6 TerraGPT-5.6 LunaGPT-5.5Claude Fable 5Claude Opus 4.8Gemini 3.1 Pro

View accessible data

Model	Effort	Estimated cost	Score	Source quality
GPT-5.6 Sol	Low	$0.856 · PROJECTED	45.4%	Exact
GPT-5.6 Sol	Medium	$1.49 · PROJECTED	61.1%	Exact
GPT-5.6 Sol	High	$2.78 · PROJECTED	69.4%	Exact
GPT-5.6 Sol	XHigh	$3.76 · PROJECTED	70.7%	Exact
GPT-5.6 Sol	Max	$6.71 · PROJECTED	72.7%	Exact
GPT-5.6 Terra	Low	$0.344	24.1%	Exact
GPT-5.6 Terra	Medium	$0.464	35.1%	Exact
GPT-5.6 Terra	High	$0.904	53.8%	Exact
GPT-5.6 Terra	XHigh	$1.7	60.2%	Exact
GPT-5.6 Terra	Max	$3.96	69.6%	Exact
GPT-5.6 Luna	Low	$0.014	1.5%	Exact
GPT-5.6 Luna	Medium	$0.044	11.3%	Exact
GPT-5.6 Luna	High	$0.156	44.2%	Exact
GPT-5.6 Luna	XHigh	$0.308	56.9%	Exact
GPT-5.6 Luna	Max	$0.606	67.2%	Exact
GPT-5.5	Low	$1.2	27%	Exact
GPT-5.5	Medium	$2.75	54%	Exact
GPT-5.5	High	$5.1	64.4%	Exact
GPT-5.5	XHigh	$7.23	67%	Exact
Claude Fable 5	Low	$3.76	59.6%	Exact
Claude Fable 5	Medium	$6.09	65.4%	Exact
Claude Fable 5	High	$9.18	68.6%	Exact
Claude Fable 5	XHigh	$13.4	69.9%	Exact
Claude Fable 5	Max	$21.6	69.7%	Exact
Claude Opus 4.8	Low	$2.29	40.8%	Exact
Claude Opus 4.8	Medium	$3.44	48.7%	Exact
Claude Opus 4.8	High	$4.28	51.8%	Exact
Claude Opus 4.8	XHigh	$8.01	54.4%	Exact
Claude Opus 4.8	Max	$13.2	59%	Exact
Gemini 3.1 Pro	High	$2.14	11.8%	Exact

BrowseComp

Score (%) vs estimated API cost · Aug 21 current estimate

Mixed evidenceSol ×0.8 · PROJECTED

1.0×

BrowseComp uses tools heavily. Adjusted Terra/Luna points are explicitly marked approximate because tool charges are not broken out publicly.

PROJECTED from current token pricing; exact task cost depends on token and tool mix

GPT-5.6 SolGPT-5.6 Sol UltraGPT-5.6 TerraGPT-5.6 LunaGPT-5.5Claude Mythos 5Claude Mythos PreviewClaude Opus 4.8Gemini 3.1 Pro

View accessible data

Model	Effort	Estimated cost	Score	Source quality
GPT-5.6 Sol	P1	$0.2 · PROJECTED	64.8%	Digitized
GPT-5.6 Sol	P2	$0.4 · PROJECTED	66%	Digitized
GPT-5.6 Sol	P3	$1.68 · PROJECTED	69.8%	Digitized
GPT-5.6 Sol	P4	$2.4 · PROJECTED	85%	Digitized
GPT-5.6 Sol	P5	$3.52 · PROJECTED	88%	Digitized
GPT-5.6 Sol	Max	$6.4 · PROJECTED	90.4%	Digitized
GPT-5.6 Sol Ultra	Ultra	$9.76 · PROJECTED	92.2%	Digitized
GPT-5.6 Terra	P1	$0.2	65%	Approximate
GPT-5.6 Terra	P2	$0.64	75%	Approximate
GPT-5.6 Terra	P3	$1.28	82%	Approximate
GPT-5.6 Terra	P4	$1.92	85%	Approximate
GPT-5.6 Terra	Max	$2.56	87.5%	Approximate
GPT-5.6 Luna	P1	$0.020	45.5%	Approximate
GPT-5.6 Luna	P2	$0.040	50%	Approximate
GPT-5.6 Luna	P3	$0.13	65%	Approximate
GPT-5.6 Luna	P4	$0.2	75%	Approximate
GPT-5.6 Luna	P5	$0.36	80%	Approximate
GPT-5.6 Luna	Max	$0.48	83.3%	Approximate
GPT-5.5	P1	$1.4	35%	Digitized
GPT-5.5	P2	$2.5	58%	Digitized
GPT-5.5	P3	$19.0	78%	Digitized
GPT-5.5	XHigh	$35.0	84.4%	Digitized
Claude Mythos 5	Not specified	Score only — no cost invented	88%	Official reference
Claude Mythos Preview	Not specified	Score only — no cost invented	87.9%	Official reference
Claude Opus 4.8	Not specified	Score only — no cost invented	84.3%	Official reference
Gemini 3.1 Pro	Not specified	Score only — no cost invented	85.9%	Official reference

GDPval-AA v2

Elo vs estimated API cost · Aug 21 current estimate

Official scores

1.0×

OpenAI publishes the comparable scores, but individual cost coordinates are not recoverable in a trustworthy public table. The site shows every official score as a reference instead of inventing x-values.

GPT-5.6 SolGPT-5.6 TerraGPT-5.6 LunaGPT-5.5Claude Fable 5Claude Opus 4.8Gemini 3.1 ProGemini 3.5 Flash

View accessible data

Model	Effort	Estimated cost	Score	Source quality
GPT-5.6 Sol	Not specified	Score only — no cost invented	1,747.8	Official reference
GPT-5.6 Terra	Not specified	Score only — no cost invented	1,593	Official reference
GPT-5.6 Luna	Not specified	Score only — no cost invented	1,591.8	Official reference
GPT-5.5	Not specified	Score only — no cost invented	1,493.7	Official reference
Claude Fable 5	Not specified	Score only — no cost invented	1,759.6	Official reference
Claude Opus 4.8	Not specified	Score only — no cost invented	1,600.1	Official reference
Gemini 3.1 Pro	Not specified	Score only — no cost invented	962.3	Official reference
Gemini 3.5 Flash	Not specified	Score only — no cost invented	1,348.8	Official reference

OSWorld 2.0

Score (%) vs estimated API cost · Aug 21 current estimate

DigitizedSol ×0.8 · PROJECTED

1.0×

Recovered model curves from the original cost chart. Terra ×0.8 and Luna ×0.2 in adjusted mode.

PROJECTED from current token pricing; exact task cost depends on token and tool mix

GPT-5.6 SolGPT-5.6 TerraGPT-5.6 LunaGPT-5.5Claude Opus 4.8

View accessible data

Model	Effort	Estimated cost	Score	Source quality
GPT-5.6 Sol	P1	$1.73 · PROJECTED	10.1%	Digitized
GPT-5.6 Sol	P2	$1.45 · PROJECTED	20.9%	Digitized
GPT-5.6 Sol	P3	$5.93 · PROJECTED	42.3%	Digitized
GPT-5.6 Sol	P4	$11.7 · PROJECTED	49.8%	Digitized
GPT-5.6 Sol	P5	$16.1 · PROJECTED	56.1%	Digitized
GPT-5.6 Sol	Max	$21.2 · PROJECTED	62.6%	Digitized
GPT-5.6 Terra	P1	$0.328	5%	Digitized
GPT-5.6 Terra	P2	$0.328	13.4%	Digitized
GPT-5.6 Terra	P3	$1.35	22.5%	Digitized
GPT-5.6 Terra	P4	$4.9	37%	Digitized
GPT-5.6 Terra	P5	$8.35	46.3%	Digitized
GPT-5.6 Terra	Max	$11.8	50.2%	Digitized
GPT-5.6 Luna	P1	$0.012	9.6%	Digitized
GPT-5.6 Luna	P2	$0.104	18.3%	Digitized
GPT-5.6 Luna	P3	$0.618	33.2%	Digitized
GPT-5.6 Luna	P4	$1.2	42.1%	Digitized
GPT-5.6 Luna	Max	$1.55	45.6%	Digitized
GPT-5.5	P1	$0.29	3.1%	Digitized
GPT-5.5	P2	$1.58	16.4%	Digitized
GPT-5.5	P3	$8.22	37.2%	Digitized
GPT-5.5	P4	$11.4	40.7%	Digitized
GPT-5.5	XHigh	$15.9	47.5%	Digitized
Claude Opus 4.8	P1	$12.9	47.1%	Digitized
Claude Opus 4.8	P2	$17.5	48.8%	Digitized
Claude Opus 4.8	P3	$20.8	49.2%	Digitized
Claude Opus 4.8	P4	$26.7	49.9%	Digitized
Claude Opus 4.8	Max	$31.3	54.8%	Digitized

AutomationBench

Score (%) vs estimated API cost · Aug 21 current estimate

Official scoresSol ×0.8 · PROJECTED

1.0×

GPT-5.6 Sol and Fable 5 cost/score pairs match the canonical Zapier leaderboard. Other OpenAI snapshot scores are shown without invented costs.

PROJECTED from current token pricing; exact task cost depends on token and tool mix

GPT-5.6 SolClaude Fable 5GPT-5.6 TerraGPT-5.6 LunaGPT-5.5Claude Opus 4.8Gemini 3.5 Flash

View accessible data

Model	Effort	Estimated cost	Score	Source quality
GPT-5.6 Sol	Max	$0.8 · PROJECTED	18.1%	Exact
Claude Fable 5	Max	$2.03	17.4%	Exact
GPT-5.6 Terra	Not specified	Score only — no cost invented	15.2%	Official reference
GPT-5.6 Luna	Not specified	Score only — no cost invented	14.9%	Official reference
GPT-5.5	Not specified	Score only — no cost invented	12.9%	Official reference
Claude Opus 4.8	Not specified	Score only — no cost invented	15.5%	Official reference
Gemini 3.5 Flash	Not specified	Score only — no cost invented	14.5%	Official reference

Evidence map

Sources and limits

Pricing and announcements link to their official OpenAI pages. Individual benchmark points retain their exact, digitized, approximate, or score-only classification; the source package does not claim a per-point public URL.

Exact = tabulated or leaderboard value. Digitized = coordinate recovered from the source chart. Official reference = published score without an invented cost.

Official pricing announcements · 2026-07-30

GPT-5.6 Luna pricing reduced by 80%; Terra pricing reduced by 20%.

Open source ↗

Official pricing announcements · 2026-08-21

GPT-5.6 Sol API and credit pricing reduced by over 20%.

Open source ↗

Official model pricing: GPT-5.6 Luna Official model pricing: GPT-5.6 Terra Official model pricing: GPT-5.6 Sol OpenAI API pricing OpenAI API changelog Original benchmark recovery record

Greenbyte point of view

Use the lowest tier that clears the workflow target.

Luna for volume; Terra for headroom; Sol when frontier capability changes the outcome. That is a product judgment—not a universal prescription from OpenAI.

Discuss an AI product decision