Fixed price or time and materials: how to pay for a software project

Fixed price vs time and materials is the first commercial decision in most software projects, and it shapes everything after it. One model gives you a known number. The other gives you flexibility. Neither is cheaper by nature. What changes is who carries the risk when the work turns out bigger or smaller than expected.

This post explains both software project pricing models in plain terms, when each one fits, and the hybrid arrangements that work well for small businesses.

Fixed price: a known number for a defined scope

The developer agrees to deliver a specific scope for a specific price. If the work takes longer than expected, that is the developer's problem. But if it takes less, the developer keeps the difference.

Good for:

• Work you can describe clearly before it starts, such as a store theme, a defined integration or a first release with a tight list of screens.
• Budgets that must be approved once, in advance.
• Buyers who want to compare quotes like for like.

Watch out for:

• Padding. The developer prices in the risk, so a fixed price often includes a cushion.
• Change friction. Anything outside the written scope becomes a change request with its own price. So if you expect to discover a lot as you go, you will spend time negotiating.
• Scope arguments. If the scope is vague, both sides will read it differently when it matters.

A fixed price is only as good as the scope behind it. The most useful scopes list what is included and also what is deliberately left out.

Time and materials: pay for the hours used

You pay an agreed rate for the time actually spent, usually invoiced weekly or monthly with a record of what was done. The scope can change as you learn, and you stop when you have what you need.

Good for:

• Work where the answer isn't known yet, such as an early product, a research spike or untangling an old system.
• Ongoing improvement after launch.
• Teams that want to steer week by week.

Watch out for:

• No ceiling. Without discipline, cost can drift.
• Visibility. You need to see progress often to judge whether hours are well spent.
• Trust. It works best with a team you have seen deliver.

The hybrids that work best

Most good arrangements mix the two.

Phased fixed price

Fix the price of the first phase, such as discovery or a first release, then price the next phase once you know more. You get a known number for the near term without pretending to know everything upfront. This is the model we use most: a written scope with a price for the first release, and later work scoped and priced as it comes.

Time and materials with a cap

Pay for hours used, up to an agreed ceiling. If the cap is approaching, the developer stops and talks to you before going further. So you keep flexibility with a limit on surprises.

Monthly retainer

A fixed monthly amount for an agreed level of ongoing work: maintenance, small changes and support. Good once software is live and needs steady care rather than a big push.

How to choose between fixed price and time and materials

Ask three questions.

1. How well can we describe the work today? Clear and stable points to fixed price. Fuzzy or likely to change points to time and materials, or a phased approach.
2. How firm is the budget? A hard number points to fixed price or a cap.
3. How much do we want to steer? If you want to change direction every week as you learn, time and materials fits better.

Questions to ask any developer

• What exactly is included in this price, and what is left out?
• How are changes requested, priced and approved?
• How often will we see working software?
• If this is time and materials, how will we know where the hours went?
• What happens to the price if the project ends early?

Payment schedules

Whatever the model, tie payments to progress you can see. For example, a deposit followed by payments at delivered milestones keeps both sides aligned. Be wary of paying most of a fixed price upfront for work you haven't seen.

What we do

Every project starts with a conversation, then a written scope: what gets built first, what it costs, and what is left out on purpose. We bill nothing before you approve it. For stores and integrations, that scope comes with a fixed price after a short walk-through of your current setup. The integrations and e-commerce pages show how we scope those.

Talk about your project

Tell us what you want built and how firm the budget is. We reply within one business day and can suggest which model fits. Start here.

Cover photo by Aaron Lefler on Unsplash.