How Much Does a Custom AI Chatbot Cost to Build and Run?
Build: $900-$2,800 fixed price. Run: usually $2-23 a month in AI usage for a small-business site, under your own keys. The full arithmetic, worked out honestly.
Two numbers, upfront. Building a custom AI chatbot costs $900 for a website assistant that answers questions and captures leads (built in about a week), or $2,800 for one trained on your documents and products, running on your site and WhatsApp with an admin dashboard. Running it — the part almost nobody explains — usually costs a small business somewhere between a few dollars and a few tens of dollars a month in AI usage, billed by the AI provider directly under your own account. The build prices are published on my pricing page; the running costs get a worked example below, because “it depends” is not an answer you can budget with.
What the build price buys
| Starter — $900 | Professional — $2,800 | |
|---|---|---|
| What it is | A website assistant that answers common questions and captures leads while you sleep | An assistant trained on your docs, products and policies — accurate answers day and night |
| Trained on | Your site content, FAQ training up to 50 Q&As | Full knowledge-base ingestion: PDFs, URLs, documents |
| Where it runs | Custom chat widget on your site | Web + WhatsApp |
| Lead handling | Lead capture + email notification | Conversation memory, admin dashboard, analytics and logs |
| Timeline | About 1 week | 3–5 weeks |
| Support | 30 days included | 60 days included |
Both are fixed-price with a 50/50 payment split, and you own everything on delivery. Larger builds — custom integrations, account lookups, multi-language — are scoped per project.
The running costs, with real arithmetic
An AI chatbot pays per use: every answer sends your visitor’s question plus the relevant slice of your content to an AI model, which bills per million tokens (a token is roughly three-quarters of a word). Prices below were checked in August 2026 against the providers’ published rates; they change, so treat the shape of the arithmetic as the durable part.
Take a busy small-business site: 500 conversations a month, four questions each. Each answer reads about 2,500 tokens of context and writes about 250 tokens of reply — roughly 5 million input tokens and 0.5 million output tokens a month in total. On that volume:
- An economical model (OpenAI’s GPT-5 mini at $0.25/$2 per million tokens, or Anthropic’s Claude Haiku at $1/$5): roughly $2–8 a month.
- A mid-tier model (Claude Sonnet at $3/$15 per million tokens): roughly $23 a month — noticeably better answers on nuanced questions, still less than most software subscriptions.
Three things keep this honest in practice. The usage runs under your own API keys — you pay the provider at cost, nothing passes through me, no markup. The build includes usage tracking and cost controls, so a busy month can’t surprise you. And model choice is a dial: most questions can go to the economical model and only the hard ones to the stronger one.
Custom build vs chatbot subscription platforms
The alternative is a hosted chatbot platform, and the trade is the same one as everywhere in software: a subscription platform rents you convenience forever; a custom build costs once and then runs at cost. Platform pricing typically stacks per-seat monthly fees with per-conversation or per-resolution charges, and the bill scales with your success. A custom bot’s only recurring cost is the AI usage above. The honest flip side: if what you actually need is a full helpdesk suite — ticketing, live-chat staffing, SLAs across a support team — a platform is genuinely the right tool, and building custom would be reinventing it badly. The custom build wins when the job is answering questions from your content and capturing leads — which is what most small-business sites actually need.
The costs nobody budgets for
- Content upkeep. A chatbot answers from your content, so it’s only as current as your pages and docs. A good build syncs automatically as content changes — but content someone never wrote can’t be synced. What a chatbot can and can’t answer covers this honestly.
- Human handoff time. The best bots know when to hand over to a person — which means a person occasionally answers. That’s the feature working, not failing; budget a few minutes a day, not a role.
- The temptation to overspec. Most businesses need the $900 tier first and an upgrade later if the traffic justifies it — not the biggest build on day one.
What you get for the money — live
The chat bubble in the corner of this page is a chatbot I built: trained on this site’s content, capturing leads, handing over to me when someone asks for a human. Its case study shows exactly what a build includes — ask it something and you’re looking at the product.
Key takeaways
- Build: $900 for a site assistant, $2,800 for a knowledge-trained multi-platform bot. Fixed price, you own it.
- Run: typically single to low double digits per month in AI usage for a small-business site (worked example: ~$2–23/month at 500 conversations; prices checked August 2026) — under your own keys, at cost.
- Platforms charge forever and scale with your success; custom costs once. Platforms still win if you need a full helpdesk suite.
- The real hidden cost is content: a bot can only answer what your content covers.
Wondering what your version would cost? Book a free intro call — describe your site and what you want answered, and you’ll get a straight number. The chatbot development service has the full details.
