Fixed price or time and materials – which is better for software projects?

Fixed price or time and materials: who bears which risk?

With a fixed price, the service provider takes on the risk that the agreed scope takes more time than planned. In return, that scope must be described precisely in advance, and every change is calculated separately. With time-and-materials billing, you bear the volume risk: you pay for what is actually worked, and in return you can change course at any time, take on new ideas or drop features.

Neither model is cheaper per se. A reputable fixed price includes a buffer for uncertainties that you pay for even if everything runs smoothly. With time-and-materials billing, a project can turn out cheaper if you prioritize consistently – or more expensive if requirements keep growing. What matters, therefore, is how precisely you can describe your project today and how much is likely to change along the way.

Fixed price, firm price or lump sum: what is the difference?

In software projects, a fixed price (German: Festpreis) and a firm price (Fixpreis) usually mean the same thing: one fixed total price for a defined scope of services. The term lump-sum price (Pauschalpreis) is common mainly in construction, where it describes a flat amount for an overall service, while a “fixed price” there sometimes also means fixed unit prices, where the total depends on the quantity. So clarify in the quote exactly what the price covers.

Also to be distinguished is billing at an hourly rate, which at its core corresponds to the time-and-materials model: the time worked is compensated at agreed rates. In any case, make sure there is a clear description of services, comprehensible rules for changes and transparent reports. This explanation does not replace legal advice; for larger projects, having the contract reviewed by a lawyer is advisable.

Hybrid models: fixed-price phase, budget cap and agile fixed price

Combinations prove their worth in practice. A project often starts with a clearly delimited concept phase at a fixed price: requirements, prototype and effort estimate are developed together. After that, there is either enough clarity for a fixed price for the implementation, or development continues on a time-and-materials basis in sprints. This way you pay for planning certainty exactly where it is possible.

Another variant is time-and-materials billing with a budget cap, also called a cost ceiling: work proceeds flexibly, but an agreed sum is not exceeded without your approval. With an agile fixed price, budget and time frame are fixed, while the exact scope of features remains negotiable and is prioritized on an ongoing basis. Which variant fits depends on project size, uncertainty and the time you have for coordination.

How to recognize a fair quote

A good quote makes transparent what is included and what is not: features, design services, interfaces, testing, documentation, commissioning and training. With a fixed price, assumptions and exclusions should be stated explicitly; with a time-and-materials model, the rates, the way time is tracked and the reporting intervals. If this information is missing, misunderstandings are inevitable – regardless of the model chosen.

After the free initial consultation, Nano Concepts prepares a transparent quote, preferably as a fixed price for a clearly defined scope. Our packages serve as a guide: Starter from €2,500, Professional from €8,000 and Enterprise priced individually. If the scope is still open, we recommend a joint concept phase so that ideas turn into a reliable basis for the calculation.