Claude Haiku 4.5 vs GPT-5.6 Terra
GPT-5.6 Terra leads overall, D to F. Claude Haiku 4.5 is about 1.6x cheaper per task. By suite, GPT-5.6 Terra takes real-world issues (D+ to D-) and spec planning (D+ to F). Take Claude Haiku 4.5 anyway when you want the side that is cheaper per task.Measured
Each agent graded on the same private suites, running headless through its own tools. Advantages are oriented so a win is a win, whichever way the metric runs.
Verdict: GPT-5.6 Terra vs Claude Haiku 4.5
GPT-5.6 Terra leads overall, D to F. By suite: GPT-5.6 Terra takes real-world issues, D+ to D- (50% vs 37% capability); GPT-5.6 Terra takes spec planning, D+ to F (53% vs 21% capability); vibe coding is even at F (22% vs 34% capability). Claude Haiku 4.5 used 1% of Claude Max 5x's weekly limit per pass, $0.012 per task at the listed price. GPT-5.6 Terra used 8% of ChatGPT Plus's weekly limit per pass, $0.019 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.6% of ChatGPT Pro 5x's weekly limit (est, about $0.019 per task). Per task, Claude Haiku 4.5 is about 1.6x cheaper ($0.012 vs $0.019). GPT-5.6 Terra is faster on real-world issues: a median task takes 2m 18s against 3m 8s. Both finished every task on it. Reasons to pick Claude Haiku 4.5 anyway: it is cheaper per task ($0.012 vs $0.019).
Changed since the previous graded week: Claude Haiku 4.5: real-world issues D+ to D-; GPT-5.6 Terra: real-world issues D to D+, real-world issues usage 9.2% to 7% of the weekly limit, spec planning C- to D+, spec planning usage 2.0% to 1% of the weekly limit, vibe coding F to D, vibe coding usage 0.5% to 0.6% of the weekly limit.
| Dimension | Claude Haiku 4.5 | GPT-5.6 Terra | Advantage |
|---|---|---|---|
| Capability | 37% | 50% | +13% (GPT-5.6 Terra leads) |
| Median task time | 3m 8s | 2m 18s | 50s faster (GPT-5.6 Terra leads) |
| Approx. task cost | $0.015 / task | $0.021 / task | $0.006 / task lower (Claude Haiku 4.5 leads) |
Claude Haiku 4.5: 8.0% of Claude Max 5x (8.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. GPT-5.6 Terra: 7.0% of ChatGPT Plus (46.0% / 5h, 7.0% / 1w) per run. Its weekly limit holds about 6 of the week's 33.6 5h windows. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Claude Haiku 4.5 | GPT-5.6 Terra | Advantage |
|---|---|---|---|
| Capability | 21% | 53% | +33% (GPT-5.6 Terra leads) |
| Median task time | 2m 8s | 2m 37s | 29s faster (Claude Haiku 4.5 leads) |
| Approx. task cost | $0.002 / task | $0.011 / task | $0.010 / task lower (Claude Haiku 4.5 leads) |
Claude Haiku 4.5: 1.0% of Claude Max 5x (1.0% / 5h) per run. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. GPT-5.6 Terra: 1.0% of ChatGPT Plus (10.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 6 of the week's 33.6 5h windows. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Claude Haiku 4.5 | GPT-5.6 Terra | Advantage |
|---|---|---|---|
| Capability | 22% | 34% | +12% (GPT-5.6 Terra leads) |
| Median task time | 4m 4s | 2m 47s | 1m 16s faster (GPT-5.6 Terra leads) |
| Approx. task cost | $0.009 / task | $0.028 / task | $0.019 / task lower (Claude Haiku 4.5 leads) |
Claude Haiku 4.5: 1.3% of Claude Max 5x (1.3% / 5h) per good solve. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. GPT-5.6 Terra: 0.6% of ChatGPT Plus (3.0% / 5h, 0.6% / 1w) per good solve. Its weekly limit holds about 6 of the week's 33.6 5h windows. Each figure is a share of that agent's own plan, so there is no delta to draw.
Grades and deltas are comparable only within a suite version. See methodology.
Frequently asked questions
Which is better for coding, Claude Haiku 4.5 or GPT-5.6 Terra?
Both clear tier 2 of 5, but GPT-5.6 Terra scores higher on capability: 50% versus 37% on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-28.
Which is cheaper per task, Claude Haiku 4.5 or GPT-5.6 Terra?
Claude Haiku 4.5 used 1% of Claude Max 5x's weekly limit per pass, $0.012 per task at the listed price. GPT-5.6 Terra used 8% of ChatGPT Plus's weekly limit per pass, $0.019 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.6% of ChatGPT Pro 5x's weekly limit (est, about $0.019 per task). Per task, Claude Haiku 4.5 is about 1.6x cheaper ($0.012 vs $0.019).
What do Claude Haiku 4.5 and GPT-5.6 Terra cost a month?
Claude Haiku 4.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-20). GPT-5.6 Terra runs on ChatGPT Plus at $20/month (public price as of 2026-07-20).