Cost to Finish an AI-Built App

Why a number given before anyone has seen the code is a guess

The question is fair and the usual answers to it are poor. Search for the cost of finishing an app and you will find ranges wide enough to hold almost any project. They cannot be narrower, because the person who wrote them has not seen yours. Two AI-built apps with the same screens can differ completely underneath: one has sound data and needs its payments connected, and the other stores the same customer in three places and has to be untangled before anything can be added.

From the outside those two look the same. A quote produced from a demo, a screen recording or a feature list is pricing the screens, and the screens are the part you have already built. The remaining work sits in what cannot be seen from the demo, so anyone quoting without reading the project has to guess at it. They protect themselves either by padding the figure or by quoting low and charging for surprises later.

What you can get before a code review is an understanding of what drives the figure, and a way to tell a careful quote from a hopeful one. The rest of this page covers both. Our general guide to app development cost deals with building from nothing, which is a different question from finishing what exists.

How much does it cost to build an app?

The things that move the cost up or down

Six things account for most of the difference between a small finishing job and a large one. None of them is the number of screens. For each, the table shows what makes the work smaller, what makes it larger, and something you can find out yourself before you speak to anyone.

Read your own project against each row and write a sentence for it. Those six sentences are a better brief than a feature list, and a team that receives them can ask sharper questions on the first call.

Cost drivers for finishing an AI-built app

Driver: How much of what exists can be kept
Costs less when: The data is organised sensibly and each feature is written once
Costs more when: The same job is done in several places, or the data has to be reorganised before anything is added
What you can find out yourself: Whether fixes stay fixed, or the same area keeps failing

Driver: Logins, payments and private data
Costs less when: The product has none of them, or they already work for a second test account
Costs more when: Money or personal records are involved and the rules for who sees what were never finished
What you can find out yourself: Whether a second account you create can see the first account's records

Driver: Number of user types
Costs less when: Everyone who signs in can do the same things
Costs more when: Customers, staff and admins each need their own screens and permissions
What you can find out yourself: A written list of each kind of user and what they may do

Driver: Integrations
Costs less when: The product stands alone, or connects to one well-documented service
Costs more when: It has to exchange data with several outside systems, or with one that is old or poorly documented
What you can find out yourself: Every outside service the product must talk to, and who holds the account for each

Driver: Web only, or phones too
Costs less when: It runs in a browser and that is all you need for launch
Costs more when: It also has to ship as an app for phones, with device testing and store review
What you can find out yourself: Whether your first customers need a phone app or would use the website

Driver: How much was ever tested
Costs less when: Several people have used it with separate accounts and you kept a list of what failed
Costs more when: Only you have used it, with one account, on one device
What you can find out yourself: The result of the main journey in a brand new account, written down

Cost drivers for finishing an AI-built app
Driver	Costs less when	Costs more when	What you can find out yourself
How much of what exists can be kept	The data is organised sensibly and each feature is written once	The same job is done in several places, or the data has to be reorganised before anything is added	Whether fixes stay fixed, or the same area keeps failing
Logins, payments and private data	The product has none of them, or they already work for a second test account	Money or personal records are involved and the rules for who sees what were never finished	Whether a second account you create can see the first account's records
Number of user types	Everyone who signs in can do the same things	Customers, staff and admins each need their own screens and permissions	A written list of each kind of user and what they may do
Integrations	The product stands alone, or connects to one well-documented service	It has to exchange data with several outside systems, or with one that is old or poorly documented	Every outside service the product must talk to, and who holds the account for each
Web only, or phones too	It runs in a browser and that is all you need for launch	It also has to ship as an app for phones, with device testing and store review	Whether your first customers need a phone app or would use the website
How much was ever tested	Several people have used it with separate accounts and you kept a list of what failed	Only you have used it, with one account, on one device	The result of the main journey in a brand new account, written down

What decides how long it takes

The schedule follows the same six drivers, with a few things of its own. The first is how quickly decisions get made. Finishing work raises questions only you can answer: what a refund should do to an account, whether a staff member may see prices. A founder who replies promptly keeps the work moving, and unanswered questions are a common reason a short job runs long.

The second is waiting on other parties. Approval from a payment provider, review by an app store, access to an account that a former contractor still holds: none of these can be hurried by writing code faster, so they are worth starting early. The third is how much of the unknown has been removed. Work that begins from a written plan based on the code runs closer to its estimate than work that begins from a demo, because fewer discoveries are left to make along the way.

This is also why we will not give you a duration on this page. Any figure would describe some other founder's project.

What you can do to lower the cost before you talk to anyone

Part of every finishing quote pays for an engineer to find out things you could have told them. The steps below cost you time and no money, and each one removes guesswork from the estimate. They are also useful if you decide to keep going alone.

The item with the largest effect is usually the launch list. Founders arrive wanting everything in the prototype finished, and some of it is not needed for the first paying customer. Features you move to the later list can be quoted separately once the product is earning.

Write the journey a first customer must complete, from arriving to paying, as numbered steps.
Split your features into two lists: needed for the first paying customer, and later.
Gather the logins for the code, the database, hosting, payments, email and the domain, and confirm each account is in your name.
Run the main journey in a brand new account and note every step that fails.
List each kind of user and what they should be able to see and change.
Stop adding features while you collect quotes, so the thing being priced holds still.
Keep a copy of the code and a saved version you know runs.

Two apps that look alike and would be quoted differently

Illustrative example

Illustrative only. Both founders are made up to show how the drivers work. It does not describe a client, and it gives no price because none would be honest.

What both built: Two founders each built a tutoring marketplace with an AI tool. Both demos show the same thing: tutors list sessions, students book and pay.
Founder one, underneath: Bookings are stored once, linked to a student and a tutor. A second test account sees only its own bookings. Payments are not connected. The launch list is short.
Founder two, underneath: Bookings are copied into separate tables for students and tutors, and the copies disagree. Any signed-in user can open any booking. She also wants a phone app and a tutor payout system at launch.
What a reviewer would say: Founder one needs finishing: connect payments, test with several accounts, set up the live site. Founder two needs the booking data reorganised and access rules written before new features are added.
Where the drivers differ: How much can be kept, private data, integrations and phones all point to a larger job for founder two. The number of screens is the same.
What founder two can change: Moving the phone app and payouts to her later list is her decision and shrinks the first phase. The data and the access rules cannot be deferred.

How to compare quotes for finishing

Quotes for finishing are harder to compare than quotes for a new build, because each team may be making a different assumption about what can be kept. Put the assumptions side by side before you put the totals side by side. A low figure that assumes all your existing code is sound and a higher one that allows for reorganising the data are describing different jobs.

Ask each team the questions below and compare the answers in writing. A team that has read the project can answer them specifically. A team that has not will answer in general terms, and that tells you how much of its figure is guesswork.

Did you read the code and the database before quoting, or work from the demo?
Which parts do you plan to keep, which to repair and which to replace, and why?
Which journeys will work at the end, and how will that be shown?
Is the price fixed for a written scope, or an estimate that can grow? What makes it grow?
What is left out: store submission, hosting setup, moving existing data, fixes after launch?
Whose accounts will the work happen in, and who owns the code at the end?
What do you need from me, and how fast, to keep to the schedule you gave?

How we price finishing work, and when to ask

We do not publish build prices, for the reason this page opens with. What we do is fixed in three steps. The consultation is free: you show us the product and where it stops, and we tell you what we would do next. The Diagnostic is a fixed-price written plan based on reading your code and database. It says what works, what blocks launch and what to build next, and it includes a fixed quote for that next phase. Its fee is credited to the build if you go ahead with us, and its price is on the pricing page.

Every build is then quoted in writing before any work starts, against a written scope, and the figure changes only if you change the scope. The plan is yours whether or not you continue with us, so you can use it to collect comparable quotes from other teams. The work is done in your repository and your accounts, and your repo and accounts stay yours.

Ask for a quote when you have a launch list and the main journey written down, and you would rather spend your time on customers than on the remaining engineering. If you are still changing what the product is, wait until it settles, because a quote for a moving target is out of date before it is signed.

Before you ask for a quote

Send these with your first message. A team that receives them has less to guess, and you will be able to hold each quote against the same facts.

The first customer's journey from arriving to paying, as numbered steps.
Your two feature lists: needed for the first paying customer, and later.
One sentence for each of the six cost drivers, describing your project.
What happened when a brand new account went through the main journey.
Where the code, database, hosting, payments, email and domain live, and whose name each account is in.
The date you want to launch, and what is fixed about it.

How we can help

We can tell you what finishing yours involves.

Book a free consultation and show us what you have built. We will go through the cost drivers with you and say whether the Diagnostic is the right next step. If it is, you receive a written plan and a fixed quote for the next phase, and you decide what to do with them.

Book a free consultation

On the project call, we’ll discuss the problem, your existing tools and what TDAT should take off your hands. Then we can define the scope and next steps.

Or call (919) 289-1231

Questions before we start

How much does it cost to finish an app I built with AI?

It depends on what is inside the project, and nobody can say before reading it. The main drivers are how much of the existing work can be kept, whether logins, payments and private data are involved, how many kinds of user there are, what it connects to, whether it needs a phone app, and how much has been tested.

Can you give me a rough figure on the first call?

No, and we would be wary of anyone who does. On the call we can tell you which drivers apply to your product and whether it sounds like finishing or something larger. A figure we can hold to comes from the Diagnostic, after we have read the code.

Is finishing cheaper than rebuilding?

Often, when the data and the access rules are sound, because the screens and flows are kept. When the foundations have to be redone, the gap narrows, and in some cases replacing one part costs less than repairing it. That comparison needs someone to read the code first.

Does an AI-built app cost more to finish than one written by developers?

Not as a rule. What matters is the state of the code and the data. AI-built projects commonly arrive with working screens and unfinished permissions, payments and testing, and projects from a development team can arrive with the same gaps.

How long will it take to finish?

That follows the same drivers as cost, plus how quickly you can make decisions and how long outside approvals take. We give a schedule with the written quote, once the scope is agreed, and not before.

What if my budget only covers part of the work?

Say so at the start. A written plan can be split into phases, with the first phase covering what the first paying customer needs. Your later list is then quoted when you are ready for it.