Fixed Price vs Time and Material vs Outcome-Based Contracts
Which software contract to use, who carries the risk, and what it costs
When you compare fixed price vs time and material, the deciding factor is how well you know your scope. Use fixed price when the scope is small, written down and unlikely to change. Use time and material (T&M) when you expect to learn and change things as you build. Use outcome-based pricing only when the result can be measured and the vendor can control it.
Updated October 2026
Fixed price vs time and material vs outcome-based: the short answer
- Fixed price: best for a defined project, such as a marketing site, a small MVP with a signed-off spec, or a migration with a known end state. You pay a known amount, but every change costs extra.
- Time and material: best for product work where requirements will move, such as a new app, an AI feature or ongoing development. You pay for hours worked, so you get flexibility but carry the budget risk.
- Outcome-based: best for work tied to a number both sides can measure, such as resolved support tickets or a performance target. It is rare in custom software, and usually mixed with a base fee.
Comparison table
| Fixed price | Time and material | Outcome-based | |
|---|---|---|---|
| Budget certainty | High, if scope holds | Low without a cap | Medium: base fee known, bonus varies |
| Total cost | Includes the vendor's risk margin | Pay for actual hours | Base fee plus a payment when the result lands |
| Speed to start | Slow: needs a full spec first | Fast: start with a backlog | Slow: needs agreed metrics and a baseline |
| Scope changes | Each one is a change request | Re-prioritize each sprint | Allowed if the target stays the same |
| Who carries the overrun risk | Vendor (until a change request) | You | Shared |
| Your control over the work | Low once signed | High | Medium |
| Best for | Small, clear, stable projects | Products, MVPs, evolving scope | Measurable results the vendor controls |
Fixed price contracts
In a fixed price contract, the vendor agrees to deliver a defined scope for one price. The US federal acquisition rules describe it as a price "not subject to any adjustment on the basis of the contractor's cost experience", with the contractor carrying the most risk (FAR 16.202-1).
When it works
The same rules say fixed price fits when there are "reasonably definite functional or detailed specifications" and the risks can be estimated up front (FAR 16.202-2). For a software project, that usually means:
- You can write the scope as a list of screens, features and acceptance criteria.
- The project is short, measured in weeks or a few months.
- You have done something similar before, so the estimate is grounded.
The hidden costs
A vendor that carries the risk prices it in. Expect the quote to include a margin above their own estimate. You don't see that margin, and you pay it even if nothing goes wrong.
Changes cost extra. Anything outside the signed scope becomes a change request, priced separately. Keyhole Software estimates that work added to the scope after the start pushes budgets and timelines up by 15% to 30% (Keyhole Software, 2026). On a fixed bid, that growth arrives as change requests.
There is also a quality risk. When hours run out on a fixed bid, the vendor has a reason to cut corners on testing and documentation. Tight acceptance criteria are your protection. The hidden cost of a bad vendor decision is usually paid after launch, not before.
Time and material contracts
In a T&M contract, you pay for hours worked at agreed rates, plus any direct costs. This is the default for most product work, and for IT staff augmentation and dedicated teams.
When it works
- Requirements will change as you learn from users.
- You want to start in days, not after weeks of specification.
- You have someone on your side who can review work and set priorities each sprint.
How to cap the risk
The main weakness is that the vendor earns more when work takes longer. The US federal rules point this out too. They say a T&M contract "provides no positive profit incentive to the contractor for cost control or labor efficiency" (FAR 16.601). Those rules require a ceiling price on every T&M contract, which the contractor exceeds at its own risk.
You can copy that idea in a commercial contract:
- Add a not-to-exceed (NTE) amount per phase. Work stops for a decision when it is reached.
- Ask for a weekly report of hours by person and by task.
- Review working software every sprint. Status reports alone are not enough.
- Agree the rate card and named roles in the contract, so seniority can't quietly change.
Outcome-based contracts
In an outcome-based contract, part or all of the payment depends on a result. A well-known example comes from AI software rather than agency work. Intercom charges 99 cents per resolution for its Fin AI agent, and bills only when a customer's issue is resolved (Stripe customer story).
What counts as an outcome
A usable outcome is measurable, has a baseline and is mostly in the vendor's control. "Page load under 2 seconds on these 10 pages" works. "Sales go up 20%" usually doesn't, because pricing, marketing and the market also move sales.
Why few agencies offer it
Outcome-based deals take longer to agree. Both sides have to settle the metric, how it is measured and what happens if your team causes a miss. A common structure is a lower base fee plus a bonus, not payment on results alone. It fits best for AI agents, performance and conversion work, and support automation.
What Edverise data shows about project minimums and rates
Most agencies set a minimum project size, and it decides which contract types are open to you. A $15,000 fixed-price project is easy to place in India and harder in the US, where 1 in 5 agencies that state a minimum want $25,000 or more.
Minimum project size, custom web application development companies (share of companies that state a minimum)
| Country | Companies stating a minimum | Under $5,000 | $5,000 to $24,999 | $25,000 or more |
|---|---|---|---|---|
| United States | 8,241 | 35% | 45% | 20% |
| India | 9,764 | 61% | 33% | 6% |
| Canada | 1,631 | 41% | 43% | 17% |
| Australia | 797 | 37% | 49% | 14% |
| United Kingdom | 2,486 | 36% | 48% | 16% |
Not stated: 1,843 (US), 2,113 (India), 316 (Canada), 173 (Australia), 483 (UK). Percentages are rounded, so rows may not add to 100.
Hourly rate bands, custom web application development companies (USD, share of all listed companies)
| Hourly rate | Canada (1,947) | Australia (970) | United Kingdom (2,969) |
|---|---|---|---|
| Under $25 or not stated | 23% | 28% | 24% |
| $25 to $49 | 20% | 19% | 21% |
| $50 to $99 | 31% | 28% | 37% |
| $100 to $149 | 24% | 22% | 17% |
| $150+ | 2% | 3% | 1% |
US and India are left out of the rate table because the listing count there is too large for an exact band split.
Based on custom web application development companies listed on Edverise in the US, India, Canada, Australia and the UK, pulled 20 October 2026. Profiles are partly compiled from public information, so treat ranges as indicative. These are listing ranges, not quoted prices.
For comparison, Keyhole Software's 2026 benchmark puts mid-level developers in North America at $90 to $149 an hour and in Asia at $25 to $35 (Keyhole Software, 2026). The listing bands in our data run lower than that benchmark, so treat both as ranges, not quotes.
How to use these numbers:
- $50 to $99 is the most common band in Canada, Australia and the UK. Use it as a sanity check on a T&M rate card.
- Small fixed-price projects narrow your pool. Under $5,000, you are limited to 35% to 41% of the agencies that state a minimum in the US, Canada, Australia and the UK.
- Large-project specialists are rare. In all five countries, under 4% of agencies that state a minimum set it at $75,000 or more.
Worked example: one project, three contracts
Take a custom web application estimated at 800 hours. Use $75 an hour, the middle of the most common band above. The vendor's estimate is $60,000. Now assume scope grows by 20%, inside the 15% to 30% range Keyhole reports.
| Contract | Terms (illustrative) | If the estimate holds | If scope grows 20% | Who pays for the growth |
|---|---|---|---|---|
| Fixed price | $60,000 estimate + 20% risk margin = $72,000; changes at $75/hour | $72,000 | $84,000 | You, through change requests |
| Time and material | $75/hour, NTE $70,000 | $60,000 | $72,000, or stop at $70,000 and decide | You |
| Outcome-based | $42,000 base + $25,000 if the target is met | $67,000 (target met) or $42,000 | Same, if the target doesn't change | Vendor |
The 20% risk margin and the outcome terms are assumptions for this example, not market figures.
What the example shows:
- If the scope really is stable, T&M is cheapest, because you don't pay the risk margin.
- Fixed price only protects you if the scope doesn't grow. Once change requests start, it can cost the most.
- Outcome-based pricing moves the overrun risk to the vendor, but only works if you can agree on a target both sides trust.
The hybrid option most buyers end up using
Many projects work best as two contracts, not one:
- A fixed-price discovery phase, often a few weeks. Its output is a spec, wireframes, an architecture plan and a priced backlog.
- T&M delivery with an NTE cap per phase, using that backlog.
You keep the price certainty where scope is unclear, then gain flexibility once you know what you're building. It also tests the vendor on a small paid piece before you commit the full budget. This is common for MVPs and mobile apps.
Clauses to check before you sign
This is general information, not legal advice.
| Clause | Fixed price | Time and material | Outcome-based |
|---|---|---|---|
| Scope | Detailed spec and acceptance criteria attached | Backlog and priorities owned by you | Metric, baseline and how it is measured |
| Changes | Change-request process with rates stated | Re-prioritization each sprint | What changes the target |
| Payment | Milestones tied to accepted deliverables | Monthly, against timesheets | Base fee schedule plus bonus trigger |
| Cost cap | The fixed price | NTE amount per phase | Base fee cap |
| IP | Transfers on payment | Transfers on payment | Transfers on payment |
| Exit | Notice period and handover of code | Notice period and handover of code | What happens to the bonus if you exit |
Whatever the model, ask for code in your own repository from day one. Many problems with the wrong tech partner start with code you can't access.
Frequently asked questions
Is fixed price cheaper than time and material?
Not usually. A fixed price includes the vendor's margin for risk, so it costs more when the project goes to plan. It only works out cheaper when scope stays fixed and the vendor's estimate turns out to be low.
Which contract is better for agile development?
Time and material. Agile teams re-plan every sprint, and a fixed price contract turns each re-plan into a change request. If you need budget certainty, add an NTE cap per phase rather than fixing the scope.
What is a not-to-exceed clause?
A not-to-exceed (NTE) clause sets the most you will pay for a phase in a T&M contract. When work reaches the cap, the vendor stops and you decide whether to add budget, cut scope or end the phase. US federal T&M contracts require a ceiling price like this.
Can I switch from fixed price to time and material mid-project?
Yes, if both sides agree in writing. It is common when a fixed-price project hits many change requests. Settle what has been delivered and paid under the fixed price first, then start T&M with a new rate card and cap.
Do software agencies offer outcome-based pricing?
Some do, mostly for AI agents, performance work and conversion projects. A common structure is a base fee plus a bonus, not payment on results alone. Expect a longer negotiation to agree the metric and how it is measured.
What is a dedicated team model?
A dedicated team is a form of time and material. You pay a monthly fee for named people who work only on your project, and you set their priorities. It suits long-running products more than one-off projects.
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