Fixed Price vs Time and Materials: Which Contract Fits?
By Nemanja Vukmirović, Lizzard Solutions. Last updated 10 November 2026.
You have two quotes for the same app. One agency offers a fixed price, the other an hourly rate with an estimate. The fixed one feels safer, but you’ve heard stories about change requests that doubled the bill.
This guide on fixed price vs time and materials shows who carries the risk in each model, which projects suit which contract, the clauses that protect you, and a worked example of the same project priced both ways.
TL;DR
- Fixed price moves delivery risk to the vendor, so it includes a buffer. It works when scope is small and truly stable.
- Time and materials (T&M) bills actual hours. It suits products that will change, such as an MVP, but needs a budget cap and regular demos.
- For most first projects, a fixed-price discovery phase followed by capped T&M sprints gives you control without paying for guesses.
Fixed Price vs Time and Materials: The Short Answer
Fixed price vs time and materials is the choice between paying one agreed amount for a defined scope (fixed price) and paying for the hours actually worked at agreed rates (time and materials). Fixed price puts cost risk on the vendor. Time and materials puts it on you, in exchange for flexibility to change direction.
Neither is cheaper by default. A fixed-price contract still uses an hours estimate underneath. The vendor simply adds a reserve because it pays for any overrun.
| Fixed price | Time and materials | |
|---|---|---|
| You pay for | An agreed scope and deliverables | Hours worked, at agreed rates |
| Who carries overrun risk | The vendor | You, within the cap you set |
| Changing scope | Formal change request, priced separately | Re-prioritize the backlog in the next sprint |
| Planning effort up front | High: detailed specification needed | Lower: a prioritized backlog is enough to start |
| Best fit | Small, well-defined jobs | Products that will evolve with feedback |
Key takeaway
The real question is not which model is cheaper. It’s how sure you are about the scope.
Action for today: write down which parts of your project you are certain about and which you expect to change after users see it.
When Is a Fixed-Price Contract the Right Choice?
Fixed price works when both sides can describe “done” in writing before any code is written. Typical examples:
- A marketing website with a known page list and an approved design.
- A specific integration, such as connecting your webshop to an accounting system with a documented API.
- A clearly bounded upgrade, like moving a site to a new server with no feature changes.
- Public or corporate procurement, where a fixed budget is a legal or internal requirement.
The catch is the specification. If it’s vague, the vendor either prices in a large reserve or interprets every gap in its own favour. Our software project brief template helps you write a scope that two agencies will price the same way.
Watch out
A fixed price with a vague scope is not fixed. It just moves the argument to the change-request stage.
Action for today: if you want a fixed price, list acceptance criteria for each feature: what a user can do, and how you will check it.
When Does Time and Materials Make More Sense?
Time and materials fits work where learning is part of the job. You build a slice, show it to users, and adjust. That is how agile teams work, and the Agile Manifesto puts it plainly: customer collaboration over contract negotiation, responding to change over following a plan.
- MVPs and new products. You don’t yet know which features users will care about. Our MVP development guide explains why the first version should stay small.
- Ongoing development of an existing product with a changing roadmap.
- Unclear technical risk, such as an old system nobody has documented or a third-party API with unknown limits.
- AI and automation projects, where accuracy is only known after testing on your real data.
The risk is drift: hours pile up without visible progress. You control it with short sprints, demos and a hard cap, not with a longer contract.
Action for today: ask any T&M vendor how often you will see working software and how they report hours.
Worked Example: One Project, Two Contracts
Here is an illustrative example (not real client figures) for a booking app with a client portal, staff calendar and online payment. Assume the team estimates the core scope at 400 hours.
| Fixed-price offer | Time-and-materials offer | |
|---|---|---|
| How the price is built | 400 hours plus a reserve for risk, quoted as one sum | Estimate of 400 hours, billed as actually worked |
| You add SMS reminders mid-project | Change request: new quote, possible delay | Added to the backlog; something lower-priority moves out or the cap rises |
| Payment API turns out harder | Vendor absorbs it (the reserve covers it) | You pay the extra hours, visible in the weekly report |
| Users ignore the client portal | You still pay for the full portal | You stop after the basic version and spend hours elsewhere |
| Final cost | Known on day one, unless scope changes | Known within the cap; depends on choices you make |
Notice the pattern. Fixed price protected you from the technical surprise. T&M protected you from building a feature nobody used. Which risk is bigger depends on your project. For the main drivers behind the 400 hours themselves, see what custom software costs and why.
Action for today: ask both vendors to show the hours estimate behind their price, not just the total.
The Hybrid Model Most Small Businesses Should Start With
You don’t have to pick one model for the whole project. A common structure:
- Discovery at a fixed price. Workshops, user flows, wireframes, technical checks and a prioritized backlog with estimates. You own the output and can take it to another vendor.
- Development as capped T&M. Work in one- or two-week sprints with a monthly budget ceiling. The official Scrum Guide describes the sprint review, where the team shows what was built and you adjust priorities.
- Fixed-price chunks where scope is clear. A well-defined integration or migration can still be quoted as a fixed package.
This keeps your exposure small at each step. If the first sprints disappoint, you stop with working code and a documented backlog instead of a half-finished fixed-price project.
Action for today: ask your shortlisted vendors whether they offer a paid discovery phase with a clear deliverable.
Contract Clauses That Protect You in Either Model
Whatever model you choose, these points belong in the contract or statement of work:
| Clause | Fixed price | Time and materials |
|---|---|---|
| Scope and acceptance criteria | Essential: defines “done” | Backlog plus definition of done per item |
| Change process | How changes are priced and approved | How priorities are changed each sprint |
| Budget control | Payment by milestone, after acceptance | Monthly cap; written approval before exceeding it |
| Reporting | Milestone demos | Weekly hours report and sprint demos |
| Code ownership and access | Repository in your account, IP transfers to you | Same |
| Exit terms | What you get if either side ends early | Notice period; handover of code and docs |
Ownership of the code and access to the repository matter most. They decide whether you can switch vendors without starting over. We cover more vendor questions in how to hire an IT company in Serbia.
Action for today: check any draft contract for a budget cap (T&M) or acceptance criteria (fixed price). If it’s missing, ask for it.
Common Mistakes When Choosing a Pricing Model
- Choosing fixed price for an idea. If you can’t describe the screens, you can’t fix the price fairly.
- T&M without a cap. An open-ended budget invites drift, even with an honest team.
- Comparing totals only. A low fixed price may exclude testing, deployment or support.
- Skipping demos. Seeing working software every sprint is your main control in T&M, as our guide to the agile software development lifecycle explains.
- No plan after launch. Hosting, fixes and updates need their own budget, often as a small monthly retainer.
Action for today: pick the one mistake above that fits your situation and fix it before you sign.
Fixed Price vs Time and Materials: FAQ
Is fixed price cheaper than time and materials?
Not by default. Both start from an hours estimate. A fixed price includes a reserve because the vendor carries the overrun risk, so for a well-run project T&M can cost less. If scope changes a lot, a fixed price can end up higher once change requests are added.
Can I switch from fixed price to time and materials mid-project?
Usually yes, if both sides agree in writing. A clean way is to close the current milestone, accept what was delivered, and continue on capped T&M with a fresh backlog. Make sure code ownership and repository access are settled before the switch.
How do I control costs on a time-and-materials contract?
Set a monthly budget cap, work in one- or two-week sprints, and ask for a weekly hours report tied to backlog items. Attend sprint demos and re-prioritize there. If progress stalls for two sprints in a row, pause and review before approving more hours.
What is a capped time-and-materials contract?
It is T&M billing with an agreed maximum, per month or for the whole phase. The vendor bills actual hours but can’t exceed the cap without your written approval. It combines the flexibility of hourly work with the budget certainty most small businesses need.
Not sure which model fits your project? See our development services or send us your brief and we’ll suggest a structure.
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