What software costs and how to budget it / Pricing and models
Fixed price vs time and materials
How you pay for software shapes how the work goes. Fixed price feels safe and makes every change costly. Time and materials with a senior team serves the outcome better when you trust the team. Neither is right for every project, and picking the wrong one turns both sides against the product.
Published July 27, 2026. Editorial.
Key takeaways
- Fixed price fits work that is well understood and will not change. It punishes change once the plan changes.
- Time and materials fits work that is still being figured out, as long as you trust the team building it.
- The model shapes incentives: fixed price makes both sides protect the contract, not the product.
- The engagement model matters less than whether the incentives reward the same result you want.
Two ways of paying dominate software work: a fixed price for a defined scope, or time and materials, where you pay for the work as it happens. People often pick one out of habit or fear rather than fit. The model you choose changes how the whole project behaves, so it is worth understanding what each one does. This page sits inside the software development cost guide because pricing model is a cost decision, not just a contract detail.
How fixed price works, and where it causes problems
Fixed price feels safe. You agree on a scope, you agree on a number, and the risk of overrun sits with the team. For work that is genuinely well understood and will not change, like a clear, bounded integration, this is a fine model and often the right one.
The problem shows up the moment the plan changes, and on real software the plan almost always changes. Under a fixed price, every change is a negotiation. The team is incentivized to build exactly what the contract says and no more, even when it learns the contract was partly wrong. You are incentivized to fit more work into the fixed scope. Both sides end up protecting the contract instead of the product. The safety was false, because the thing you actually wanted, a good product, is now competing with the paperwork.
Fixed price also pushes the team to add extra to the number, because they carry the risk of everything you forgot to specify. So you often pay more for the certainty than you would have for the work.
There is a deeper problem too. To fix a price, the team has to fix the spec, which means every detail has to be decided before anyone knows if it is right. On new software, a lot of those early decisions turn out to be wrong once real users try the product. A fixed price locks you into the wrong version of the plan and charges you again to change it. You get certainty about a number and lose flexibility about the thing that actually matters, the product.
How time and materials works, and what it needs
Time and materials means you pay for the work as it is done. This fits the reality of most software, where you learn as you build and the plan improves along the way. When the team discovers the first plan was wrong, it just adjusts, instead of stopping to renegotiate. That keeps everyone focused on the product rather than the contract.
The condition is that time and materials only works when you trust the team. Without trust, paying by the hour feels like agreeing to pay any amount. This is why the model is inseparable from who you hire. A senior team you trust, working time and materials with frequent feedback, tends to serve the outcome better than any fixed price. A team you do not trust should not be working on either model, and the real fix is a better team, covered in our choosing a software development partner guide.
Incentives are the real question
Look at the whole picture and the choice is not really about price certainty. It is about what the incentives reward. A good pricing model makes the team want the same thing you want: a product that works, delivered well, without waste. Fixed price rewards protecting the contract. Time and materials with a trusted senior team rewards the outcome.
This is why we generally favor time and materials with a senior team for anything new or still changing, and reserve fixed price for work that is truly bounded and understood. The in-house vs outsourcing cost page covers the related question of who does the work, and our custom software development cost piece looks at pricing from the buyer's side.
Time and materials does not mean unlimited spending with no control. A good version of it comes with frequent feedback: short cycles, visible progress, and a running conversation about what is worth doing next. You see the work as it happens and direct it. That visibility is what replaces the false comfort of a fixed number. You are not buying certainty about a total, you are buying the ability to spend each week on the most valuable thing, which on new work is worth far more.
Match the model to the work
A mixed approach exists and often works best. You can fix the price of a small, well-understood first phase, such as a discovery and a plan, then move to time and materials once you know enough to build with confidence. This lets you test the team on a bounded piece before committing to open-ended work, and it gets the plan clear before you start paying for the expensive part. It is a common structure for a well-run build, and it avoids the worst problems of each model.
The honest rule is simple. If the work is bounded, understood, and unlikely to change, a fixed price can make sense. If the work is new, still being figured out, or likely to change as you learn, time and materials with a team you trust will serve you better. Do not pick the model that feels safest. Pick the one whose incentives match the kind of work you actually have. The in-house vs outsourcing cost page covers the other part of this decision, who does the work. If you want help deciding, get in touch and we will talk through which fits your project and why.
Best for
- Fixed price: bounded, well-understood work that will not change, like a clear integration
- Time and materials: new or evolving work, with a senior team you trust and frequent feedback
- Either one: only when the incentives reward the product you want, not the paperwork
Avoid if
- Do not use fixed price for anything new or still being figured out, because every change becomes an argument
- Do not use time and materials with a team you do not trust, because it feels like agreeing to pay any amount
- Do not pick a model on which feels safest, before checking what its incentives actually reward
Check before you decide
- Confirm the scope is truly fixed before agreeing to a fixed price, not just fixed on paper
- Confirm you trust the team enough to pay for work as it happens before choosing time and materials
- Confirm the model makes the team want the same outcome you want, not the opposite
Common questions
What is the difference between fixed price and time and materials?
Fixed price means you agree on a scope and a number, and the team carries the overrun risk. Time and materials means you pay for the work as it is done. Fixed price suits bounded, unchanging work. Time and materials suits work that is still evolving, as long as you trust the team.
Which pricing model is cheaper for software development?
Which pricing model is cheaper depends on the work. Fixed price often looks cheaper but pushes the team to add extra to the number for everything you forgot to specify, and every change becomes a costly negotiation. Time and materials with a senior team you trust often costs less overall on evolving work, because nobody is protecting a contract instead of the product.
When should I use a fixed price contract?
When the work is genuinely bounded, well understood, and unlikely to change, like a clear and well-documented integration. The moment the plan is likely to change, fixed price turns every change into a negotiation and pushes both sides to protect the contract instead of the product.
When does time and materials make more sense than fixed price?
When the work is new or still being figured out, which describes most software, because the team can adjust as it learns instead of stopping to renegotiate every change. Time and materials only works well when you trust the team, since without that trust paying for hours worked can feel like an open-ended commitment rather than a controlled one.
Is time and materials pricing safe from costs growing out of control?
It is safe when it comes with frequent feedback: short cycles, visible progress, and a running conversation about what is worth doing next, so you see the work as it happens and direct it. Without that visibility and without trust in the team, paying by the hour does feel like agreeing to pay any amount, which is why the model is inseparable from who is doing the work.
Can I combine fixed price and time and materials on one project?
Yes, and it is often the strongest approach. A common pattern is to fix the price of a small, well-understood first phase, such as a discovery and a plan, then move to time and materials once the scope is clear enough to build with confidence. This tests the team on a bounded piece before committing to open-ended work.
Why does the pricing model matter more than the price itself?
Because the model shapes what the team is incentivized to want. Fixed price rewards protecting the contract, so both sides end up negotiating instead of improving the product. Time and materials with a trusted senior team rewards the outcome, since the team adjusts as it learns rather than treating every discovery as a change order to argue over.
Does a fixed price contract actually reduce risk on a software project?
Less than it appears to. To fix a price, the team has to fix the spec, meaning every detail is decided before anyone knows if it is right, and on new software many of those early decisions turn out wrong once real users try the product. A fixed price buys certainty about a number while locking in the wrong version of the plan and charging again to change it later.