updated 2026-04-24 · gpt-5.6 · unreleased · tracking

GPT-5.6?

GPT-5.6 is the hypothetical next half-step in OpenAI's GPT-5 family. GPT-5.6 is unreleased as of April 24, 2026 — GPT-5.5 just shipped April 23. This page tracks every leak, cadence signal, and expected diff vs GPT-5.5, with sources cited inline. Acknowledge: 5.6 may be a half-step, or OpenAI may skip it and ship GPT-6.

// TL;DR. GPT-5.6 has not been announced. The OpenAI 5.x cadence (5.0 → 5.2 → 5.4 → 5.5) suggests a late-Q2 to early-Q3 2026 window if a half-step ships before GPT-6. Expected diff: small benchmark gains, lower hallucination, possibly 2M context. Pricing speculative ($5–$8 in / $30–$50 out). Try GPT-5.5 on ZeroTwo today and get gpt-5.6 day-zero with no upgrade.
$ try gpt-5.5 while you waitsee gpt-6 tracker
$ no chatgpt plus required·published
##overview

What is GPT-5.6?

GPT-5.6 is, as of April 24, 2026, an unreleased hypothetical successor to GPT-5.5 in OpenAI's GPT-5 family. There is no OpenAI announcement, no API model ID, and no Codex internal picker leak yet. The name follows a plausible 5.x cadence — GPT-5 shipped August 7, 2025, GPT-5.2 in January 2026, GPT-5.4 in March, and GPT-5.5 on April 23, 2026 per OpenAI's launch post — but a half-step before GPT-6 is not guaranteed.

Acknowledge the uncertainty: GPT-5.6 may not ship at all if OpenAI's next release is large enough to warrant the GPT-6 name. Per analyst reporting at TokenMix, the public name is decided by the size of the performance delta — small delta means a 5.x increment, large delta means a new major version. Whether the delta over GPT-5.5 is 5.6-shaped or 6.0-shaped is the open question this page tracks.

The most-rumoured next capability is persistent cross-session memory. Sam Altman has called current AI memory "GPT-2 era" relative to what's coming. If memory ships under a 5.x banner, gpt-5.6 is the candidate; if held until GPT-6, the 5.x family ends with 5.5. Per Epoch AI's compute analysis, the entire 5.x family has been compute-flat — improvements come from post-training and inference, not a base-model scale-up. That constrains how much a 5.6 release could plausibly improve.

##expected diff · gpt-5.6 vs gpt-5.56

What's new in GPT-5.6 vs GPT-5.5.

Six speculative diffs against the GPT-5.5 baseline. Every line is cited; every claim is flagged as expected, speculative, or extrapolated. Use this as a forecast, not a spec sheet.

Reasoning (GPQA Diamond)
−85.7% (GPT-5.5)
++1–3 pp expected

Half-step releases historically nudge benchmark scores by 1–3 percentage points — gpt-5.5 over 5.4 was tighter than the 5.4 over 5.2 jump.

source · Artificial Analysis
Coding (SWE-bench Verified)
−88.7% (GPT-5.5)
++1–2 pp expected

GPT-5.5 already pushed SWE-bench Verified to 88.7%; remaining headroom is small without a base-model scale-up.

source · OpenAI
Hallucination rate
−−60% vs 5.4 (GPT-5.5)
+Marginal further drop

GPT-5.5 already claimed a 60% hallucination reduction over 5.4. Half-step releases typically improve calibration by another 5–15%.

source · OpenAI
Context window
−1.0M (GPT-5.5) / 1.05M (GPT-5.4)
+1.0–2.0M (speculative)

A 2M-token context appeared in unverified April 10 leaks; if any 5.x model ships it before GPT-6, gpt-5.6 is the candidate.

source · FindSkill
Pricing (per 1M tokens)
−$5 in / $30 out (GPT-5.5)
+$5–$8 in / $30–$50 out

Speculative. OpenAI doubled prices from 5.4 to 5.5; a 5.6 patch would likely hold or modestly raise pricing.

source · TokenMix
Agentic tool use
−Multi-step tool calling (GPT-5.5)
++ persistent memory (rumored)

Persistent cross-session memory is the most-rumored next capability; whether it lands in 5.6 or is held for 6.0 is undecided.

source · Voiceflow
$ try_now --baseline gpt-5.5
Run GPT-5.5, Claude Opus 4.6, Gemini 3.1 Pro, and Grok 4 side-by-side on ZeroTwo's multi-model chat. When GPT-5.6 ships, it lands in the model selector day-zero — no upgrade fee, no separate ChatGPT Plus subscription.
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##signal feed · sourced + scored6

Every credible GPT-5.6 signal, dated.

Six dated signals as of April 24, 2026. Each carries a 1–5 star credibility score: 5 stars = on-record from OpenAI, 1 star = anonymous unverified claim. We don't publish anything we can't link.

·BASELINE★★★★★

GPT-5.5 ships — naming committee buys time

OpenAI shipped GPT-5.5 on April 23, 2026 at $5 input / $30 output per million tokens, per OpenAI's official blog post. With a half-step release on the table, the 5.x cadence so far (5.0 → 5.2 → 5.4 → 5.5) makes a 5.6 increment plausible — but GPT-5.5 already ate the .5 slot. Whether the next release is 5.6 or jumps to 6.0 is undecided.

source · OpenAI
·WATCH-CHANNEL★★★★★

Codex internal picker leaked GPT-5.5 — same channel will surface 5.6

GPT-5.5 briefly appeared in OpenAI's internal Codex model picker on April 22, hours before Sam Altman heavily hinted at the Thursday release, per Piunika Web's reporting. Every prior 5.x release has leaked via Codex Pro accounts; the same surface is the highest-probability first signal for any gpt-5.6 model ID.

source · Piunika Web
·ODDS★★★★★

Polymarket: 'next OpenAI release by' contracts are repricing

Polymarket's release-date contracts have been repricing daily through April 2026. The April 30 'GPT-6' contract has fallen to roughly 45–72% depending on the day, with Q3 2026 priced as a non-trivial tail. Any half-step gpt-5.6 release would likely arrive in the late-Q2 to early-Q3 window if OpenAI maintains its ~6-week cadence.

source · Polymarket
·CAPABILITY★★★★★

Altman: memory and agents are next — 'GPT-2 era' framing

Sam Altman has repeatedly described current AI memory as being in the 'GPT-2 era' relative to what's coming, signalling persistent cross-session memory as the headline feature for the next major release. Whether that ships under a 5.6 banner or 6.0 is undetermined; multiple analysts at Fello AI argue OpenAI uses minor-version increments to ship narrower capability updates between major launches.

source · Fello AI
·COMPUTE★★★★★

Epoch AI: GPT-5.x has been compute-flat — gpt-5.6 unlikely to break that

Epoch AI's training-compute analysis argues GPT-5 used less compute than GPT-4.5 because OpenAI was waiting on Stargate Abilene's GB200 capacity. The 5.x family has been compute-flat: 5.2, 5.4, 5.5 were post-training and inference improvements over the same base. A gpt-5.6 — if it ships — would almost certainly continue that pattern, with the next compute scale-up reserved for GPT-6.

source · Epoch AI
·PRICING★★★★★

Pricing speculation: $5–$8 in / $30–$50 out per 1M tokens

Speculation only. TokenMix's pricing forecasts extrapolate from the GPT-5.4 ($1.75 in / $14 out) and GPT-5.5 ($5 in / $30 out) jumps. A gpt-5.6 release would most likely sit at or slightly above 5.5 pricing — $5–$8 input / $30–$50 output per million tokens — with the same 1M-token context and 2× multiplier on long-context modes. Treat all numbers as speculative until OpenAI ships.

source · TokenMix (forecast)
##what we're tracking6

Live signals to monitor for GPT-5.6.

The exact channels we refresh whenever the GPT-5.6 rumour cycle starts moving. Anything hits these, this page updates within a day.

##on the record

What insiders are saying about the next 5.x.

"GPT-5.5 is a sign of the future. What's notable about GPT-5.5 is it demonstrates that rapid AI improvement is continuing."
— Ethan Mollick, professor at Wharton, in One Useful Thing · April 2026

Mollick's framing matters because it reframes GPT-5.5 as a cadence-marker, not an endpoint. If improvement is "continuing," either gpt-5.6 ships in the next 6–10 weeks under the same naming convention, or OpenAI uses the same window for the GPT-6 cut-over. Per Simon Willison's GPT-5 reporting, the cadence has been "remarkably consistent" since the August 2025 launch — there's no signal of OpenAI breaking it.

##prep

How to be ready for GPT-5.6 day-zero.

The cheapest hedge while waiting for GPT-5.6 is also the most honest test of whether you actually need it. Run the same prompts against the four current frontier models — GPT-5.5, Claude Opus 4.6, Gemini 3.1 Pro, Grok 4 — and see which wins for your workflows. ZeroTwo's multi-model chat is the only consumer surface that puts all four side-by-side in one window. If GPT-5.5 already wins for you, gpt-5.6 will too; if Claude Opus 4.6 wins, gpt-5.6 has to clear a higher bar.

When OpenAI ships gpt-5.6, ZeroTwo adds it to the model selector the same day — every previous frontier launch (GPT-5, GPT-5.2, 5.4, 5.5; Claude Opus 4.5, 4.6; Gemini 3 Pro; Grok 4) appeared within hours. That means no separate ChatGPT Plus subscription, no API keys, and no waiting list. See our ChatGPT alternative comparison for the full multi-model breakdown, and the GPT-5 spec sheet for the baseline gpt-5.6 has to beat.

For developers, the highest-leverage prep is building agentic tooling now against GPT-5.5's existing multi-step tool calling. Per Voiceflow's analyst write-up, the next 5.x model's expected persistent-memory and longer-context features extend — not replace — the current Codex / Operator surface. Build for tool use today and the upgrade path is mostly free. For background on the broader frontier, see also Grok 4, Perplexity, and the full GPT model family.

## Key takeaways

  • GPT-5.6 is unreleased and unconfirmed as of April 24, 2026 — GPT-5.5 just shipped April 23.
  • OpenAI's GPT-5.x cadence has been roughly 6 weeks between releases; if 5.6 ships, late Q2 to early Q3 2026 is the most defensible window.
  • Expected diff vs GPT-5.5 is incremental — 1–3 pp on benchmarks, lower hallucination, possibly a 2M context, possibly persistent memory.
  • Pricing is purely speculative — most likely $5–$8 input / $30–$50 output per million tokens, holding or slightly above GPT-5.5.
  • OpenAI may skip 5.6 and ship the next major release as GPT-6 — the 5.x family has been compute-flat per Epoch AI.
  • The cleanest hedge: use GPT-5.5 alongside Claude, Gemini, and Grok on ZeroTwo today and get gpt-5.6 day-zero with no upgrade.
##faq

Frequently asked about GPT-5.6.

Ten direct answers — sourced from OpenAI, Polymarket, Epoch AI, Fello AI, and TokenMix.

$ What is GPT-5.6?

GPT-5.6 is a hypothetical incremental successor to OpenAI's GPT-5.5 model. As of April 24, 2026, GPT-5.6 has not been announced, has not appeared in OpenAI's API model list, and has not leaked in OpenAI's internal Codex model picker. The name follows the 5.x release cadence (5.0 → 5.2 → 5.4 → 5.5), but with GPT-5.5 having shipped only on April 23, 2026 and GPT-6 already in the rumour cycle, OpenAI may skip 5.6 entirely.

$ When will GPT-5.6 be released?

There is no confirmed release date for GPT-5.6. OpenAI's GPT-5.x cadence so far has been roughly 6 weeks between releases — 5.0 in August 2025, 5.2 in January 2026, 5.4 in March 2026, 5.5 in April 2026. If OpenAI maintains that cadence and ships another half-step before GPT-6, late Q2 2026 to early Q3 2026 is the most defensible window. Polymarket's general OpenAI release-date contracts price meaningful probability across May–September 2026.

$ GPT-5.6 vs GPT-5.5 — what would actually change?

The expected diff is incremental: small benchmark gains (1–3 percentage points on GPQA Diamond and SWE-bench Verified), further hallucination-rate reduction, possibly an extension of the context window toward 2 million tokens, and rumored persistent cross-session memory. Pricing would likely sit at or slightly above GPT-5.5's $5 input / $30 output per million tokens. None of this is confirmed by OpenAI.

$ How much will GPT-5.6 cost?

Pricing is purely speculative. GPT-5.4 was $1.75 input / $14 output per million tokens; GPT-5.5 doubled to $5 / $30. TokenMix's pricing forecast suggests gpt-5.6 would most likely hold at $5 / $30 or rise modestly to $5–$8 input / $30–$50 output, with a 2× multiplier for long-context modes above 200K tokens. ChatGPT consumer pricing would likely stay at $20/month Plus and $200/month Pro.

$ Will OpenAI skip GPT-5.6 and jump straight to GPT-6?

Possible. Multiple analysts at TokenMix and Fello AI report OpenAI's naming committee has not committed to a 5.6 release — the next public name will hinge on the size of the performance delta. A small delta would ship as gpt-5.6; a meaningful step-change in compute, memory, or agentic capability would be reserved for GPT-6. Per Epoch AI, the GPT-6 base-model scale-up is enabled by Stargate Abilene's GB200 capacity that landed late 2025.

$ How does GPT-5.6 compare to Claude Opus 4.6 and Gemini 3.1 Pro?

GPT-5.5 currently leads Terminal-Bench 2.0 at 82.7%; Claude Opus 4.6 leads on extended-context reasoning and writing benchmarks; Gemini 3.1 Pro leads multimodal and price-performance; Grok 4 leads SWE-bench Verified at 75% on its own evaluation. Any GPT-5.6 release would have to push past Claude Opus 4.6 on reasoning and Gemini 3.1 Pro on multimodal to reset the frontier — historically the half-step releases close gaps rather than widen leads.

$ Should I wait for GPT-5.6 before subscribing to ChatGPT Plus?

Probably not. ChatGPT Plus locks you into one provider at $20/month for GPT-5.x access. ZeroTwo bundles GPT-5.5, Claude Opus 4.6, Gemini 3.1 Pro, Grok 4, and 60+ other models for $29.99/month, with day-zero access to GPT-5.6 (or GPT-6, whichever ships first) the moment it appears in OpenAI's API. Side-by-side comparison is the only reliable way to tell whether a half-step model actually changes your workflow.

$ What is the expected GPT-5.6 context window?

GPT-5.4 already extended to 1.05 million tokens and GPT-5.5 ships at 1 million tokens. A 2-million-token context appeared in unverified April 10 leaks predicting an April 14 launch that did not materialise. If any 5.x model ships a 2M context before GPT-6, gpt-5.6 is the candidate — but the claim originates from a low-credibility anonymous source and should be treated as rumour.

$ How can I try GPT-5.6 the moment it launches?

Sign in to ZeroTwo and use GPT-5.5 alongside Claude, Gemini, and Grok today. ZeroTwo adds new frontier models to the model selector within hours of release — GPT-5, GPT-5.2, GPT-5.4, and GPT-5.5 all appeared inside a day of OpenAI's announcement. Your existing ZeroTwo subscription unlocks gpt-5.6 the moment it appears in the OpenAI API, with no upgrade required.

$ Is GPT-5.6 a real model?

Not yet. As of April 24, 2026, GPT-5.6 is not confirmed to exist. This page is a forward-looking tracker — every benchmark, pricing, and capability claim is explicitly flagged as expected, speculative, or extrapolated from prior 5.x releases. The first definitive signal will be either an OpenAI blog post, a 'gpt-5.6' entry in the OpenAI API model list, or a leak via the Codex internal model picker.

Want to actually try the closest available model? Pick GPT-5.5 from the model selector on ZeroTwo's chat — gpt-5.6 will appear there day-zero with no upgrade.

# author
ZeroTwo Editorial

The ZeroTwo editorial team tracks every frontier model release, runs benchmark comparisons across our 60+ model catalog, and updates this page with primary-source citations within a day of any new credible signal.

published · updated

Don't wait for GPT-5.6_

Use GPT-5.5 — plus Claude, Gemini, and Grok — on ZeroTwo today. The moment OpenAI ships gpt-5.6 (or skips it for GPT-6), it lands in your model selector. No upgrade fee. No ChatGPT Plus required.

$ try gpt-5.5 on zerotwo