Model comparison

GPT-5.6 Terra vs Gemini 3.6 Flash

What we tested these two models on, what each test found, and the published rates and limits that hold whatever the job is. Two jobs have a full write-up so far, and both of them split between the two models rather than going to one.

Aug 25, 2026 · 6 min read

How we compared them
One task at a time

We are not claiming one of these two is the better model. On both jobs we tested, the answer was to use each of them for a different part of the work.

Two jobs have a full write-up behind them, and nine further articles put one of these two models against a different one. The cards below open the two, and the index further down lists all nine, so nothing here has to be taken on trust. The two vendor knowledge-work figures come from different harnesses, and the page says so instead of ranking on them.

What we compared is set out underneath. First the published rates, input formats and limits both models bring to any job, then the model-level dimensions where the evidence separates them. Those hold whatever you are doing. Which of the two to reach for does not, which is why the jobs come first.

One thing to be clear about before the tables. This page compares the two models through their APIs in one neutral setup, not the apps around them, so a slide add-on or a document viewer is not part of anything here.

By the job
Which model wins which work

Neither model wins in general, so this pair is settled one job at a time. Each card names a job we tested, says which model took which part of it and why, and opens the full test. Two jobs on this pair have that test so far, and the index further down carries the rest of the library.

The shared facts
What each one costs and takes

The published figures both models bring to any job. The last column reads them for the pair rather than for one task.

Spec
GPT-5.6 Terra
Gemini 3.6 Flash
Why it matters
Context window
1,050,000 tokens
1,048,576 tokens
Either one holds a messy source pack, so capacity does not decide this13
Max output
128,000 tokens
65,536 tokens
Only Terra can return a long document and its notes in a single pass13
Input price
$2 per million, $0.20 cached
$0.75 per million, promotional through Dec 31, 2026 (then $1.50)
The source pack is input, so Gemini is cheaper on the side that carries the volume12
Output price
$12 per million
$3.75 per million, promotional through Dec 31, 2026 (then $7.50)
Drafts and variants are output, and this is the wider of the two gaps12
Long-context pricing
$4 in and $18 out above 272,000 input tokens
No separate long-context tier published
A large research pack re-prices Terra's whole request rather than the excess12
Inputs
Text and images
Text, images, video, audio and PDF
Gemini takes a wider range of source formats without a conversion step13
Reasoning controls
None through max, with controls over carrying reasoning between turns
Minimal through high thinking
Terra's turn controls help when the same material is rebuilt under new constraints43

Figures from OpenAI and Google documentation with speed measured independently. Terra's cached input rate is stated here in the fuller form two other pages use.

Head to head
How they compare beyond one task

The general layer, underneath the jobs above. These are model-level dimensions, so they hold whatever the job is. The two knowledge-work figures come from different vendors at different settings, and that row says so rather than presenting them as a match.

Dimension
Better choice
Why the edge exists
Best evidence
General reasoning
GPT-5.6 Terra
An independent composite index across knowledge, reasoning and coding, which is directional for structuring work rather than a grade on it
57 against 52 on the index56
Vendor-reported knowledge work
GPT-5.6 Terra, not a clean match
Each vendor reports its own figure at its own top setting and through its own harness, so this supports a direction and not a margin
1,593 against 1,421 as reported by each vendor78
Returning a long document in one pass
GPT-5.6 Terra
Twice the output ceiling, which decides whether the draft and its notes come back together
128,000 output tokens against 65,53613
Rebuilding under new constraints
GPT-5.6 Terra
It exposes controls over whether reasoning carries between turns, which is what a rebuild depends on
Documented turn-scoped reasoning controls4
Cost at volume
Gemini 3.6 Flash
Lower on both input and output at Gemini's current promotional rate, and no long-context tier at all, where Terra re-prices its whole request above 272,000 tokens
$0.75 and $3.75 against $2 and $12, at Gemini's current promotional rate12
Generation speed
Gemini 3.6 Flash
Faster measured output, which is the clearest operational difference on this pair
About 210 tokens per second against 1209
Range of source formats
Gemini 3.6 Flash
Audio, video and PDF go in directly, so a recording does not need a transcription step first
Text, images, video, audio and PDF against text and images13

OpenAI's presentation benchmark material concerns GPT-5.6 Sol rather than Terra and cannot be inherited across tiers, so it is not used here. Terra is also absent from the preliminary category leaderboards where Gemini ranks well, so those tables prove nothing about this pair.

Everything we tested
Both models across the library

Every article on this site that puts one of these two models under a graded test, grouped by model. The two on this exact pair are the cards higher up the page.

Where else we tested GPT-5.6 Terra

Where else we tested Gemini 3.6 Flash

What this cannot tell you
The limits of the comparison above

Neither model has been graded publicly on a specific document job on this pair, so every quality row above is a proxy.

The capability index is a composite rather than a grade on any real deliverable. The two knowledge-work figures are each vendor reporting on itself, at different top settings and through different harnesses, which is why the row calls itself directional. The long-context recall result is Google's own with no matching independent figure for Terra at the same length. And a benchmark lead in reasoning says nothing about whether the language it produces sounds like a person.

Playgram is not the right buy for everyone either. If one person needs one model and nothing else, a single vendor subscription is simpler and cheaper than a workspace built for a team.

The safest last step is to test the shape of your own material rather than a generic prompt from the internet. A fair test needs the same setup on both sides: the same sources, the same prompt and the same place to run them, so the result reflects the models and not the tool around them. In practice that is harder than it sounds, because most teams end up running one model in one app and the other somewhere else on a separate subscription, which tilts the comparison before the first answer arrives. The cleaner the setup, the more the difference you see is really GPT-5.6 Terra against Gemini 3.6 Flash.

Use both on one brief
Right here inside Playgram

One workspace makes the two-pass version of this easy. You send the source pack once, read both answers side by side, and hand the structure from one model to the other without setting anything up twice.

Try it on three briefs you actually have. Put the same messy material in front of the latest GPT and Gemini models, keep the structure that reads best, and continue straight into the wording pass instead of rebuilding the context for it.

The same memory then travels with the team, over the latest GPT, Claude, Gemini and Grok models and many more, all in one place, with retired models turned off and new ones added as they ship10.

Team memory

Shared across everyone and every model.

Project memory

Scoped to a campaign or document set.

Personal memory

Your own working style, kept private.

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Frequently asked
questions

Two jobs so far: building a talk outline and translating a support reply, which are the two cards below. Nine further articles put one of these two models against a different one, and the index further down lists them. Both of the tests on this pair split the work between the two models rather than handing it to one.

About three fifths cheaper on input and more than two thirds cheaper on output, at Gemini's current promotional rate. Gemini lists $0.75 and $3.75 per million against Terra's $2 and $12. That rate holds through the end of 2026, then Gemini's price is due to rise to $1.50 and $7.50 from January 2027, still under Terra on both tokens. The gap widens further on a large source pack, because Terra re-prices its whole request to $4 and $18 above 272,000 input tokens, while Gemini publishes no separate long-context pricing tier at all.

Gemini, by a clear margin. It accepts text, images, video, audio and PDF directly, while Terra takes text and images. If your inputs arrive as recordings or PDFs, that removes a conversion step rather than just saving money.

That is usually the better answer on this pair. Use Terra for the pass that decides what the argument is and how it changes when the brief moves, then move to Gemini for wording and variants, where speed and price matter and the structure is already settled. Keep the same source material and the same instructions on both sides so you are comparing the models rather than two setups.

No. Run the same prompt on both and compare the answers, or switch between them mid-conversation. You choose after reading both answers instead of guessing up front.

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