3-Line TL;DR

  • GPT-6.1 Terra launched on October 26 at $1 input and $5 output per 1M tokens, half of GPT-6.1 Sol, and OpenAI says it matches GPT-6 Astra on one agent test at a tenth of the per-token price
  • Next to GPT-3 in 2020, Terra's input is 60x cheaper and it reads about 500x more text at once; GPT-3's MMLU score now costs about 860x less (Epoch AI)
  • The top model still costs real money; what keeps getting cheaper is yesterday's top intelligence, and Terra is the latest step

Terra is back, at half price

  • OpenAI released GPT-6.1 Terra on October 26 (OpenAI changelog)
  • GPT-5.6 had a Terra, but GPT-6 dropped it, as I noted in the Astra Minor post; now it's back between Sol and Luna
  • OpenAI pitches it for reading screens, working across apps and writing (OpenAI)
  • Standard API price is $1 input, $0.05 cached input and $5 output per 1M tokens
  • Prompts over 272K tokens pay 2x input and 1.5x output for the whole request
  • Context is 1.05M tokens, with up to 128K tokens of output

OpenAI developer page for GPT-6.1 Terra showing $1 input and $5 output per 1M tokens, with input and output boxes highlighted

Source: OpenAI developer docs — captured Oct 27, 2026, boxes added by HSL

  • In ChatGPT it's in Work and Codex for Plus, Pro, Enterprise and Edu; OpenAI's help page also lists Business
  • OpenAI's numbers, all from its own tests:
    • On Agents' Last Exam at medium effort, Terra scores 15 points above GPT-5.6 Terra at about a third of the cost
    • On that same test it performs on par with Astra at a tenth of the per-token price, and finishes tasks over 3x faster than Astra or Sol
    • On Terminal-Bench 4.0 at max effort it solves 50.3% versus 21.5% for GPT-5.6 Terra
  • OpenAI still recommends Sol or Astra for the hardest coding work

Bar chart: a 100K-in, 20K-out job costs $2.00 on Astra, $0.40 on Sol, $0.20 on Terra and $0.02 on Luna

Made by HSL — OpenAI pricing, standard rates checked Oct 27, 2026; illustrative token counts, not a measured task

  • Same token counts, so this compares sticker prices, not finished work
  • A model that needs more tokens or retries for the job can lose its price lead

2020: GPT-3 cost $60 per million tokens

  • OpenAI opened its GPT-3 API as a private beta in June 2020 (OpenAI)
  • Its biggest model, davinci, cost $0.06 per 1K tokens, or $60 per 1M, until OpenAI cut it to $20 on September 1, 2022 (OpenAI notice)
  • ChatGPT arrived on November 30, 2022 as a free preview
  • In March 2023 the ChatGPT model came to the API at $2 per 1M tokens, which OpenAI called 10x cheaper than its existing GPT-3.5 models (OpenAI)
  • Two weeks later GPT-4 launched at $30 input and $60 output (OpenAI)

Timeline of OpenAI launch prices per 1M tokens from GPT-3 davinci at $60 through GPT-4 at $30/$60 to GPT-6.1 Terra at $1/$5

Made by HSL — OpenAI launch posts and pricing page; launch prices, many were cut later

  • GPT-4o came in May 2024 at $5 / $15, and GPT-4o mini in July at $0.15 / $0.60 (OpenAI)
  • GPT-5 in August 2025 cost $1.25 / $10 (OpenAI)
  • The flagship never got cheap: GPT-4 was $30 / $60 in 2023, and Astra is $10 / $50 today
  • What collapses is the price of a level once it stops being the top

GPT-3 vs Terra: 60x cheaper, 500x more to read

Scorecard: GPT-3 (2020) vs GPT-6.1 Terra (2026) on price, context, answer length, images and tools

Made by HSL — GPT-3 paper (2,048-token context), OpenAI price notice, Terra docs; davinci list price before September 2022

  • Put the 2020 flagship next to the 2026 mid-tier model and the gap gets a little silly
  • Input is 60x cheaper and output 12x cheaper
  • GPT-3 could read 2,048 tokens at once, about three pages of text
  • Terra reads 1.05 million tokens, roughly several novels in one go
  • In 2021, OpenAI's Codex paper found GPT-3 solved 0% of the simple Python problems in HumanEval (paper)
  • Terra solves 50.3% of Terminal-Bench 4.0, a far harder test where an agent works in a real terminal (OpenAI's own number)
  • Those are different tests, so it isn't "50 points better"; it's zero versus half of a much harder exam
  • On the MMLU knowledge test GPT-3 scored 43.9%, where random guessing gets 25% (Epoch AI)
  • OpenAI hasn't published a Terra MMLU score; GPT-4o mini already scored 82% in 2024
Summarize a 100K-token book into 2K tokens GPT-3 (2020 price) GPT-6.1 Terra
Requests At least 50 chunks, then stitch One request
Token cost $6.12 $0.11

Our calculation: 100K × $60 + 2K × $60 per 1M tokens vs 100K × $1 + 2K × $5 per 1M tokens; GPT-3's chunk overlap and stitching would add more

  • About 55x cheaper, for a job GPT-3 couldn't even hold in memory at once

Same score, a fraction of the price

  • Epoch AI tracked the cheapest model that reaches a fixed benchmark score (Epoch AI)
  • Depending on the score, that price fell 9x to 900x a year; matching GPT-4 on PhD-level science questions got about 40x cheaper per year
  • GPT-3's MMLU score cost $60 per 1M tokens in late 2021 and $0.07 in October 2024
  • GPT-4's MMLU score went from $37.50 in March 2023 to $0.18 in February 2025, about 200x in under two years

Log-scale chart: cheapest price for GPT-3-level MMLU falls from $60 to $0.07, GPT-4-level from $37.50 to $0.18 per 1M tokens

Made by HSL — Epoch AI data, price weighted 3:1 input to output, reasoning models excluded

  • MMLU is a multiple-choice knowledge test and may be in training data, so treat it as a rough yardstick
  • These are list prices, not OpenAI's actual costs
  • a16z called it "LLMflation" and estimated about 10x cheaper per year for the same capability (a16z)
  • Sam Altman wrote that the cost of a given level of AI falls about 10x every 12 months (Sam Altman)
  • Epoch adds that the fastest drops are recent, so it's unclear they will last

Two vending machines: the 2020 one takes a pile of coins for one speech bubble, the 2026 one pours out a heap for one coin

Same coin, more answers

  • Terra fits the pattern: OpenAI says Astra-level results on its agent test now cost a tenth per token, less than two months after Astra launched

So when should I pick Terra?

Job Start with Switch when
Screens, forms, documents in bulk GPT-6.1 Terra It keeps missing steps and retries pile up
Hard coding or open-ended problems GPT-6.1 Sol or GPT-6 Astra A cheaper model passes the same checks
Simple, very high-volume tasks GPT-6 Luna Accuracy drops below what you need
ChatGPT or Codex on a subscription GPT-6.1 Terra The task needs Sol-level coding
  • OpenAI's own example is reading invoices and typing them into accounting software
  • In ChatGPT Work and Codex, OpenAI says the same limit covers more Terra tasks than GPT-5.6 Terra, and far more than Sol or Astra
  • High effort settings burn through that limit faster, as one Reddit user found below

Community Reactions

  • r/ChatGPT user ExplanationSenior104 reports Terra doing good Codex work in about one minute versus roughly 15 minutes with Sol 6.1 (Reddit)
  • r/ChatGPT user bulutarkan reports two Terra xhigh prompts cutting the five-hour allowance from 100% to 90% in under two minutes (Reddit)
  • r/OpenAI user Lucky_Creme_5208 questions Terra's purpose, saying Sol 6.1 beats it at nearly equal cost outside Agents' Last Exam (Reddit)
  • r/LocalLLaMA user Endonium worries that money-losing low prices can't last and API or subscription prices may rise (no measurements) (Reddit)

Q&A (Field Notes)

  • Q. Do free ChatGPT users get Terra?
    • Not at launch. OpenAI lists Plus, Pro, Enterprise and Edu, and its help page adds Business
  • Q. Is GPT-6.1 Terra just a cheaper Sol?
    • It's tuned for screen work, images and writing; OpenAI still points the hardest coding to Sol or Astra
  • Q. Is it really half the price of GPT-5.6 Terra?
    • Input fell from $2 to $1, and output from $12 to $5, so output dropped even more than half
  • Q. Will prices keep falling 10x a year?
    • Nobody can promise that. Epoch notes the fastest drops are recent and may not last
  • Q. Does a cheaper token always mean a cheaper job?
    • No. Prompts over 272K tokens cost more, and higher effort or retries add tokens