Any page offering a price range for custom software is guessing, because the same one sentence description can honestly produce quotes an order of magnitude apart. What is worth having instead is a method: know which assumptions move the number, insist that every bidder states theirs, and compare those rather than the totals.
Software development cost estimation: what a credible estimate contains
The GAO's Cost Estimating and Assessment Guide sets out what separates a reliable estimate from a number: a stated purpose and scope, a technical baseline description, a work breakdown structure, written ground rules and assumptions, the data it was built from, the estimating method used, sensitivity and risk analysis, and a plan to update it against actuals. You will not get all of that from a small agency, and you can reasonably ask for the assumptions, the breakdown and the risks, which is most of the value.
Estimating software development costs: the assumptions that move the number most
How many user roles see different data, because permissions multiply states. Whether a backend exists or must be built. How many external systems are integrated and how well documented they are. Whether designs exist and are complete. Whether data migration is in scope. Whether the product handles regulated data. Whether one platform or two. Each of these can double a figure, and a quote silent on all seven is a hope with a number attached rather than an estimate.
Anchor the labour in a software cost, then judge the rest
Software is built by people, and the Bureau of Labor Statistics puts the US median annual wage for software developers at $135,980 in May 2025 and for quality assurance analysts and testers at $104,300. Convert those to a loaded hourly cost and you have a floor to judge against: a quote far below what the labour plausibly costs is buying juniors, templates or offshore hours, any of which can be fine as long as you know which one you are buying.
Set the software development budget for the years after launch, not just the build
A custom system carries a permanent cost: security and dependency updates, platform and browser changes, hosting, monitoring and the engineering time to keep it current. Ask every bidder for an annual figure alongside the build price. A bidder who cannot produce one has not operated a system past its first year, and the omission usually means the quote is priced to reach launch rather than to have a working product.
Questions people ask about software development costs
How much does custom software development cost?
No honest answer exists without assumptions, because the same description produces quotes an order of magnitude apart. Establish roles and permissions, whether the backend exists, integrations, designs, migration, regulated data and platform count, and the range collapses.
What should a software development cost breakdown contain?
Scope and purpose, a work breakdown, written ground rules and assumptions, the estimating method, and a risk analysis, along the lines the GAO cost estimating guide describes. From a small agency, the assumptions, breakdown and named risks are the achievable and most valuable part.
How do we sanity check a custom software development price?
Against the labour. BLS puts the US median annual wage for software developers at $135,980 in May 2025 and testers at $104,300. A quote far below what the hours plausibly cost is buying juniors, templates or offshore time, which is fine if known.