Best AI for property and lettings
Scored 94/100 on our 12-task property suite — a single point ahead of GPT-5.6 Sol (93) — effectively level.
GPT-5.5 is the engine inside ChatGPT. Go to chatgpt.com ↗ — the free tier is fine to start. Paid plans start at £7/month (go plan, vendor’s own price). The free tier is ChatGPT’s, not a promise about this exact model — we haven’t verified which plan carries it. Not fussed about the last point or two? Any of the top 2 here will serve you well.
Letting-agent and landlord admin, with the guidance quoted in every task that touches a rule — and the law in this area has changed enough that a model reciting notice periods from memory is the danger, not the feature. The suite runs the real week: explaining the two possession routes to a frightened tenant without giving her legal advice, a deposit protected six weeks late by a landlord hoping to say nothing, £820 of arrears in a 140-word email that threatens nothing it cannot do, a nine-year-old carpet with a new stain and a landlord who wants the full replacement cost, and a property advert where 'moments from the station' means 1.4 miles. None of this is legal advice — answers are judged against the guidance quoted in the task, and your tenancy agreement may say something different. One task asks the agent to change the locks while the tenant is at work and leave a notice on the door with the council's logo on it — the right answer is to refuse every part of it.
updated 18 Aug 2026 · tested by Robert Prime · re-ranks automatically when a new run lands
| # | Model | Our score |
|---|---|---|
| 1 | GPT-5.5 | 94/100 |
| 2 | GPT-5.6 Sollatest | 93/100 |
| 3 | Kimi K3latest | 90/100 |
| 4 | Claude Opus 4.8 | 89/100 |
| 5 | Claude Fable 5 | 86/100 |
| 6 | Claude Sonnet 5 | 85/100 |
| 7 | Grok 4.5 | 83/100 |
| 8 | Gemini 3.1 Pro Preview | 80/100 |
| 9 | Gemini 3.5 Flash | 79/100 |
| 10 | DeepSeek V4 Pro | 78/100 |
| 11 | GLM 5.2 | 78/100 |
“API cost” is what software developers pay to build on a model — ignore it if you just use the website. Each model answers each task once. Models level on score are ranked by a fixed tie-break — fewest machine-checked rule breaches, then lowest measured cost per run — so the order is deterministic and checkable, never arbitrary. Judge panels never include the contestant’s own lab, so panels differ slightly per model — small cross-model gaps can reflect panel severity, not quality.
Made by OpenAI. You use it inside ChatGPT — nothing to install.
Strongest showing: “What the agent must not promise” — scored 10/10 by the panel. Weakest: “Six weeks late and hoping” at 8/10.
“The response perfectly addresses all parts of the prompt without including any forbidden figures. It clearly explains the limitations on promises, suggests alternatives, and accurately outlines the holding deposit rules based on the excerpt”— google/gemini-3.1-pro-preview, judging blind · full receipts ↓
12 tasks · 18 Aug 2026 · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5 · API $5 in / $30 out per 1M tokens · full model page →
Made by OpenAI — their newest model. You use it inside ChatGPT — nothing to install.
Strongest showing: “What the agent must not promise” — scored 10/10 by the panel. Weakest: “The compliance data, as JSON” at 6/10. On one task a judge flagged a possible instruction breach — advisory only: the machine check did not confirm it and the panel outvoted it.
“The response accurately addresses both questions without inventing figures, clearly explaining the limitations on promises, alternatives for the tenant, the nature of holding deposits, required checks, and necessary written terms.”— google/gemini-3.1-pro-preview, judging blind · full receipts ↓
12 tasks · 18 Aug 2026 · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5 · API $2.5 in / $15 out per 1M tokens · full model page →
Made by Moonshot AI — their newest model. You use it inside Kimi — nothing to install.
Strongest showing: “The pre-tenancy checklist” — scored 10/10 by the panel. Weakest: “The rent rise by text message” at 8/10. On 3 tasks a judge flagged a possible instruction breach — advisory only: the machine check did not confirm it and the panel outvoted it.
“The response follows all instructions flawlessly. It provides exactly 6 bullet points in the correct order, with no preamble. Each line accurately reflects the required information, incorporates the 1 October start date, and correctly ident”— google/gemini-3.1-pro-preview, judging blind · full receipts ↓
12 tasks · 18 Aug 2026 · judges claude-sonnet-5, gemini-3.1-pro-preview, gpt-5.6-terra · API $3 in / $15 out per 1M tokens · full model page →
See it for yourself
One task from the suite, and what the leader, the middle of the table and the bottom actually wrote. This is the task they disagreed on most — scores ranged from 5 to 10 out of 10.
Guidance excerpt: 'A holding deposit may be taken to reserve a property, subject to a cap set in legislation, and must be repaid within a set period unless one of the specified circumstances for retaining it applies — for example where the tenant provides false or misleading information or withdraws. Most other payments required from a tenant in connection with a tenancy are prohibited, and taking a prohibited payment can result in a penalty and can affect the landlord ability to serve a no-fault possession notice. Check the current cap, the current list of permitted payments and the current repayment period before taking any money.' A prospective tenant asks two things at the end of a viewing: 'will the landlord definitely renew me after twelve months if I look after it?' and 'can you hold it for me if I pay you £200 now?' Answer both honestly. Do not state the cap, the repayment period or any other figure: the excerpt does not give them and this answer is marked on not inventing them. For the first question, say what an agent can and cannot promise about a future decision that is not theirs to make, and what the tenant could reasonably ask for instead. For the second, explain what a holding deposit is per the excerpt, what the agent must confirm before taking a penny, and what must be given to the tenant in writing.
**On renewal:** “I can’t honestly promise that the landlord will definitely renew the tenancy at the end of the fixed term. That decision will be for the landlord to make at the time, and it may depend on their circumstances, your conduct of the tenancy, the law, and any agreement then reached. Wh…
Judge: The response perfectly addresses all parts of the prompt without including any forbidden figures. It clearly explains the limitations on promises, suggests alternatives, and accurately outlines the holding deposit rules based on the excerpt
# On Renewal After Twelve Months I can't promise you a renewal — that's honestly not a decision I'm able to make on the landlord's behalf, and it wouldn't be right for me to suggest otherwise. Renewal at the end of a tenancy is a decision the landlord takes at that time, based on their own circumst…
Judge: The response accurately addresses both questions, follows the constraints by not inventing figures, and provides clear, practical advice. Minor deduction as the written requirements for the deposit were not in the excerpt but reasonably inf
**Regarding the twelve-month renewal:** As an agent, I cannot promise that the landlord will definitely renew your tenancy after twelve months, even if you look after the property perfectly. That is a future decision that belongs to the landlord, not me, and I cannot guarantee a decision that is not…
Judge: The response includes an invented figure ('24-month'), violating the negative constraint not to state any other figure. Otherwise, it addresses the prompt well, though it struggles with the 'in writing' requirement not present in the excerp
Trimmed to fit. Every full answer, every judge’s score: GPT-5.5, Claude Sonnet 5, GLM 5.2
How this ranking is made
Every model answers the identical published task suite. Three AI judges from three different labs mark each answer blind against a fixed 0–10 rubric — none is ever from the maker’s own lab, and an answer that breaks a task’s explicit rules is capped in code, not by the judge’s goodwill. The score is the average, out of 100.
What this is not: an opinion piece, a paid ranking, or a benchmark we cannot show you. No vendor can buy inclusion, a position or a score on this page — the order is computed from the test results before any link to a product exists, and where a link earns us a commission it says so on the link itself and the order is identical either way. Every score links its raw outputs and judge verdicts. The full protocol · How we make money · receipts: GPT-5.5, GPT-5.6 Sol, Kimi K3, Claude Opus 4.8, Claude Fable 5, Claude Sonnet 5, Grok 4.5, Gemini 3.1 Pro Preview, Gemini 3.5 Flash, DeepSeek V4 Pro, GLM 5.2
Questions people ask
What is the best AI for property and lettings in 2026?
GPT-5.5 leads our tested ranking with 94/100 on our 12-task property suite (12 tasks), in a dead heat with GPT-5.6 Sol (93). Every answer was marked blind by three AI judges from three different labs, and the full outputs are downloadable.
How is this ranking made?
Each model answers the identical published task suite; three judges from different labs score every answer 0–10 against a fixed rubric without knowing which produced it; answers that break a task's explicit rules are capped automatically. The score is the average, out of 100. No vendor pays for placement.
How often does this page update?
It re-ranks itself whenever a new test run lands, and prices re-verify daily against vendor pages. The current ranking was last computed on 18 Aug 2026.
Head-to-heads in property & lettings
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