Who pays when estimates miss?
Fixed price vs time and materials: every estimate is wrong. The contract decides who pays.
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Senior engineers
No juniors. No middlemen.
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Fixed price
Overruns are on us.
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Live in weeks
Weekly demos on staging.
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You own the code
100% of the IP, day one.
Use fixed price for an MVP or any scope you can write down; use time and materials for ongoing work that changes weekly. Under fixed price the vendor carries estimation risk, so quotes run about 10–15% above the T&M estimate (Empat). Under T&M you pay every overrun. In an illustrative 600-hour project at $70/h, a 30% overrun turns a $42k T&M estimate into $54.6k; fixed price with a 15% premium stays at $48.3k.
Fixed price vs time and materials
| Factor | Fixed price | Time and materials (T&M) |
|---|---|---|
| What you pay for | An agreed written scope | Hours worked at agreed rates |
| Who carries estimation risk | The vendor | You |
| Typical price level | About 10–15% above T&M estimate (Empat) | The estimate, plus any overrun |
| Budget predictability | High | Low to medium |
| Flexibility | Changes re-scoped and quoted | Reprioritise any week |
| Vendor incentive | Finish efficiently | More hours, more revenue |
| Best for | MVPs, rescues, defined integrations | Ongoing product work, research |
| Main failure mode | Vague scope, disputes | Budget drift with nobody watching |
Premium figure: vendor-published estimate (Empat), approximate.
Fix what you can write down
A first product, a rescue or a defined feature fits on a few pages. Once written, a fixed price makes the vendor own its estimate. That is the incentive you want.
After launch, users drive the roadmap. Use a monthly team with a weekly demo.
The worst model sits in between: a 'fixed price' on a vague scope, where every ambiguity becomes a change request.
Illustrative example: a 30% overrun
Illustrative example with stated assumptions. 600 estimated hours at an assumed $70/h (CEE senior range $60–80).
| Scenario | Time and materials | Fixed (+10%) | Fixed (+15%) |
|---|---|---|---|
| Price at signing | $42,000 estimate | $46,200 | $48,300 |
| Estimate right (600 h) | $42,000 | $46,200 | $48,300 |
| Overrun 15% (690 h) | $48,300 | $46,200 | $48,300 |
| Overrun 30% (780 h) | $54,600 | $46,200 | $48,300 |
| Overrun 50% (900 h) | $63,000 | $46,200 | $48,300 |
| You add a feature (+60 h) | +$4,200, start any time | +$4,200 quoted first | +$4,200 quoted first |
Illustrative example. Hours, rate and overruns are assumptions; the premium is Empat's estimate. Fixed price wins whenever the real overrun exceeds the premium. New features are never free in either model.
What makes a fixed price real
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Written scope
Roles, workflows, integrations, exclusions
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Acceptance criteria
Checkable on a staging URL
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Change clause
You see the price first
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Overrun clause
Vendor mistakes are vendor cost
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Your repo
100% IP from first commit
When fixed price wins
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First product or MVP
You cannot audit hours and the board wants one number. See MVP development cost.
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Rescue after an audit
Remaining work can be listed and priced. See software rescue.
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Defined integration
Clear inputs, clear outputs, a known system on each side.
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Hard budget or deadline
A grant, a funding milestone, a seasonal launch.
When time and materials wins
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Product after launch
Priorities follow user feedback. A dedicated team on monthly billing fits.
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Research
You do not know yet whether the approach works.
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Engineers in your team
Staff augmentation is T&M by nature: your lead directs the work.
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Small, frequent changes
Quoting each would cost more than doing it.
Fixed phases, flexible roadmap
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Free scoping call · Week 0
Goals, users, workflows. Prepare with our MVP scope checklist.
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Written scope and fixed quote · Week 1
Features, acceptance criteria, exclusions and price in one document.
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Fixed-price build · Weeks 2–12
Weekly demos on staging. Your changes are quoted before work starts.
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Monthly team · After launch
The same engineers continue monthly with 2 weeks' notice.
Fixed price. We eat the overruns.
On MVP and rescue fixed-scope projects, the quoted price for the agreed written scope is what you pay. If our estimate was wrong, the extra hours are our cost. Your changes are quoted separately first. Teams and augmentation bill monthly with 2 weeks' notice; the guarantee does not apply there, because you direct the hours.
Get a fixed-price quoteQuestions buyers ask us
Is fixed price or time and materials better for software development?
Fixed price when the scope can be written down: MVPs, rescues, defined integrations. Time and materials when priorities change weekly and someone technical steers. Many projects use both: a fixed-price first phase, then a monthly team.
Why is fixed price more expensive than time and materials?
The vendor carries the risk that the estimate is wrong and prices it in, roughly 10–15% per Empat. If the real overrun would have exceeded that, fixed price was cheaper. It is the price of a ceiling on your budget.
What happens if I want to change scope on a fixed-price project?
The change is scoped and quoted before work starts. You decide whether to add it, swap it for something else, or move it to the next phase. It should be a short written conversation, not a renegotiation.
How do I control costs on a time and materials contract?
Set a monthly budget cap, review a prioritised backlog weekly, see a demo every week, and ask for hours per feature. Keep the notice period short so you can stop if it drifts.
Does fixed price mean lower quality?
It can, if the vendor protects its margin by cutting tests. Put acceptance criteria, automated tests and code ownership in the scope, so quality is part of what the price buys. Ask to see a recent pull request.
Which contract model do software agencies prefer?
Many prefer time and materials: the client carries the risk and every extra hour is revenue. Ask any agency what happens when its own estimate is wrong. The answer tells you who really carries the risk.
Keep reading
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MVP development
Fixed-price MVP development. A senior team scopes it in writing, ships a deployed build early, demos weekly and launches a focused MVP in typically 8–12 weeks.
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Software rescue
Stalled at 80%? Vendor vanished? AI-generated code nobody understands? We audit it for free, tell you to salvage, refactor or rebuild, then fix it for a fixed price.
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Dedicated development team
A dedicated development team of 2–4 senior engineers working on your product. Monthly billing, cancel with 2 weeks’ notice, 100% of code and IP is yours.
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MVP development cost
What an MVP costs in 2026 by complexity, region and pricing model: market ranges, timelines, hidden costs and an illustrative booking-app estimate.
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Custom software cost
What custom software costs in 2026 by project type: internal tools, portals, integrations, SaaS and rescues. Market data from Clutch and vendor surveys, hidden costs and examples.
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Freelancers vs agency
Freelancer, agency or in-house team for your MVP? A three-way comparison of cost, speed and risk, an illustrative cost example, and when each option is the right call.
No 40-page proposals. A fixed price and a start date.
Bring your scope, or bring the mess. We will write it down and price it.