GPT-5.5 vs GPT-5.6 Luna for travel planning
Dead heat: 93 each
Same 12 travel planning tasks, marked blind by three rival labs. Tested 16 Aug 2026.
Where they differed most
Total this France trip honestly and find the savings: ferry Portsmouth-Caen £248 return with the car; 6 nights gîte £540; fuel for roughly 700 miles at 38mpg with petrol around £1.45 a litre; eating out 6 nights at roughly £70 a night; museums about £40 for the family; plus the forgotten costs you think deserve a line. Show the arithmetic plainly, give a realistic grand total, then the two easiest savings that do not gut the holiday.
Assuming the **700 miles includes all driving** and using UK imperial mpg: ### Core costs | Item | Arithmetic | Cost | |---|---:|---:| | Ferry Portsmouth–Caen return with car | given | **£248** | | 6 nights gîte | given | **£540** | | Fuel | 700 miles ÷ 38 mpg = 18.4 gal; 18.4 × 4.546 = 83.7 litres; 83.7 × £1.45 | **£121** | | Eating out | 6 × £70 | **£420** | | Museums | given | **£40** | **Core subtotal:** £248 + £540 + £121 + £420 + £40 = **£1,369** --- ### Forgotten-but-realistic costs | Item | Estimate | Cost | |---|---:|---:| | Su…
## Core costs | Item | Arithmetic | Cost | |---|---:|---:| | Ferry, return with car | Given | **£248** | | Gîte, 6 nights | Given | **£540** | | Fuel | 700 miles ÷ 38 mpg = 18.42 imperial gallons; × 4.546 = 83.8 litres; × £1.45 | **£121** | | Eating out | 6 × £70 | **£420** | | Museums | Given | **£40** | **Subtotal: £248 + £540 + £121 + £420 + £40 = £1,369** ## Costs commonly forgotten Assuming a family, and that the 700 miles includes the main driving but not every tiny local trip: | Forgotten cost | Sensible allowance | |---|---:| | Gro…
Task by task
| Task | GPT-5.5 | GPT-5.6 Luna |
|---|---|---|
| The impossible family holiday | 9 | 9 |
| Three days, one toddler | 9 | 9 |
| Hand luggage, February, Krakow | 9 | 9 |
| Will we make it? | 9 | 9 |
| Total the real cost | 9 | 8 |
| The ferry is cancelled | 9 | 9 |
| Check, don't assume | 10 | 9 |
| Declare it or regret it | 9 | 9 |
| Next September's weather | 10 | 10 |
| Brief the dog-sitter | 10 | 10 |
| Tokyo by Thursday, sharp by Friday | 9 | 10 |
| Refuse the customs dodge | 10 | 10 |
Full receipts: GPT-5.5, GPT-5.6 Luna · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5
Questions people ask
Which is better for travel planning: GPT-5.5 or GPT-5.6 Luna?
They tied at 93/100 on our travel planning suite — for this job, pick on price or the product you already use.
How was this tested?
Both models answered the identical published travel planning tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.
More travel planning head-to-heads: GPT-5.6 Luna vs GPT-5.6 Sol · GPT-5.5 vs GPT-5.6 Sol · Claude Fable 5 vs GPT-5.6 Luna · GPT-5.6 Luna vs GPT-5.6 Terra · Claude Sonnet 5 vs GPT-5.6 Luna · GPT-5.3-Codex vs GPT-5.6 Luna
Full ranking: Best AI for travel planning · model pages: GPT-5.5, GPT-5.6 Luna