Software development cost calculator
Describe what you want built in plain language and get a costed range back in about two minutes — with the effort behind every line, the third-party subscriptions the thing will actually need, and levers you can pull to see what changes the number. No email, no gate, nothing held back.
What software actually costs to build
Starting points for a first release, before anything specific to your project is known. The low figure is an MVP scoped to the smallest thing that works; the high figure is a full product.
| Project type | Typical effort | MVP | Full product |
|---|---|---|---|
| Marketing website | 6 person-weeks | $16,000 | $24,000 |
| Internal tool | 12 person-weeks | $31,000 | $48,000 |
| AI / automation | 16 person-weeks | $42,000 | $64,000 |
| Data & analytics | 16 person-weeks | $42,000 | $64,000 |
| E-commerce | 18 person-weeks | $47,000 | $72,000 |
| Web app or platform | 20 person-weeks | $52,000 | $80,000 |
| Mobile app | 20 person-weeks | $52,000 | $80,000 |
These are planning figures, not quotes, and they exclude the running costs below. Rebuilding an existing system runs about fifteen per cent above greenfield; adding to one runs well under. Run your own project through the calculator for a range that reflects it.
Six things move the number, and nothing else does
Every one of these is a lever in the calculator. Knowing which one is expensive is usually worth more than the estimate itself.
What kind of product it is
The single biggest factor. A marketing site and a multi-tenant platform are not the same job with a different number of pages — they carry roughly three times the engineering between them before anything else is decided.
How much of it you build now
An MVP scoped to the smallest thing that works lands near two thirds of a full product. Adding to a system that already exists is cheaper again; rebuilding one is about fifteen per cent dearer than greenfield, because you inherit its edge cases before you delete them.
Web, mobile, or both
Web and mobile together is not double — shared services and one backend absorb a lot of it — but it is close to a forty-five per cent premium over either alone. Internal-only tools come in slightly under public ones: fewer browsers, fewer states, no marketing surface.
How many people will use it
Scale changes engineering gently and running costs steeply. Ten times the users is nowhere near ten times the build, but it is roughly ten times the API calls — which is why the estimate separates build cost from monthly running cost instead of blending them into one misleading figure.
How fast you need it
A compressed schedule costs about eighteen per cent more for the same delivered work, because parallelising a project buys calendar time with coordination overhead. A relaxed timeline saves a little. Neither changes what gets built.
What it has to run on top of
Model APIs, transactional email, hosting, error tracking, payment processing, a vector store. These are priced at list, monthly, dated, and shown as their own line — because a build quote that ignores them is a build quote that comes back in month two.
- Engineering effort across every workstream the plan needs, in person-weeks
- Product and interface design, sized to how much of it already exists
- Testing, deployment pipeline and the handover documentation
- Third-party subscriptions and metered usage, at list price, dated
- A calendar duration derived separately from effort, because adding people shortens a project sub-linearly
- Your own team's time reviewing, deciding and supplying content
- Content, copywriting and photography unless the plan names them
- Licences you already hold, and any enterprise pricing you have negotiated
- Ongoing feature work after handover, which is quoted per phase
- Taxes and anything that depends on where you are incorporated
Third-party prices in the breakdown are list prices in US dollars, checked as of 2026-02. Vendors move them; the tool shows the date so you know how stale the figure is.
Two minutes, five questions
- 01Describe what you want builtOne or two sentences in plain language. "A customer portal with login, invoices and support tickets" is enough to start.
- 02Answer five questionsProject type, how much of it ships first, web or mobile, roughly how many people will use it, and when you need it.
- 03Read the range and the breakdownA cost band appears with every workstream priced separately, plus the monthly subscriptions and usage the solution would need.
- 04Pull the leversChange scope, platform, scale or timeline and the number re-prices instantly, so you can see which of your requirements is the expensive one.
- 05Take it awayNo email is required at any point. If you want a fixed price, a one-to-two week discovery sprint is the next step.
Why this number is defensible
Most instant quote tools are a lookup table with a lead form attached. This one separates judgement from arithmetic on purpose.
The model plans, it never multiplies
ZAC decides what work a project needs and which products it will pay for. Every dollar figure after that is produced by a deterministic pricing engine at a fixed blended rate.
Effort is measured in person-weeks
Each workstream in the plan carries an effort figure. Money is effort times rate — one multiplication, in one place, that you can check.
Every plan is checked against a baseline
Baseline effort per project type exists as a sanity anchor, so a model having a bad day cannot quote a six-month platform as three weeks or a landing page as a year.
The same input always prices the same
No randomness in the arithmetic. If you run the same project twice you get the same number, and if you challenge a line we can walk you through where it came from.
Estimator or Consultant?
This page prices something you have already decided on. If you are still working out what to build, start with the AI consultant instead — it ends with a cost band too.
| ZAC Estimator | ZAC Consultant | |
|---|---|---|
| The question it answers | What will this cost, and where does the money go? | What should we build, and why that? |
| What you bring | A rough idea of what you want built | A business problem, in plain language |
| What you get back | A cost range, a line-by-line breakdown and adjustable assumptions | A solution recommendation, prototype, feature plan and timeline |
| Includes a price | Yes — that is the whole output | Yes — a cost band at the end |
| Includes a visual prototype | No | Yes |
| Time it takes | About two minutes | About three minutes |
| Email required | Never | Only to email the PDF |
How much does it cost to build a custom software application?
How much does it cost to build a mobile app?
Is this calculator free, and do I need to give an email address?
How accurate is an instant software cost estimate?
Why do other agencies not publish prices?
Does the estimate include running costs?
Can I change the assumptions?
Do you charge hourly?
What if my project is bigger than anything listed?
Get your range in two minutes. No email required.
ZAC Estimator returns a real cost band with the breakdown and the assumptions written out, so you can challenge them.