How to Compare Development Estimates from Different Vendors
Practice3 minInnovialabs editorial team
In short
Estimates differ because vendors understood the task differently. Put them in one table by feature and stage, mark the gaps, and compare scope first, total price second.
The short answer: why estimates differ so much
If three vendors quote three very different amounts, they most likely estimated three different projects. One included design, testing and launch, another only coding, a third added a risk buffer. A total with no breakdown tells you almost nothing. Compare the scope of work first, money second.
Where the differences come from
- Different readings of the task. A short brief gets filled in differently in each vendor's head.
- Different stages included. Analysis, design, testing, DevOps and documentation may or may not be there.
- Pricing model. Fixed price usually includes a buffer for uncertainty; Time & Materials does not, but the final bill can grow.
- Team composition. Senior developers cost more per hour but often need fewer hours.
- Existing building blocks. Some vendors reuse their own components, others write everything from scratch.
Step 1. Give everyone the same input
Comparison starts before you receive any estimates. Send every vendor the same document: product goal, key features, platforms, integrations and rough timeline. Forward answers to one vendor's clarifying questions to all the others, so nobody estimates a "different" project.
Step 2. Put the estimates in one table
Split the project into rows by feature and stage, with vendors as columns.
| Item | Vendor A | Vendor B | Vendor C |
|---|---|---|---|
| Analysis and prototype | included | no | included |
| UI/UX design | included | included | template only |
| User account area | estimated | estimated | estimated |
| Payment integration | estimated | no | estimated |
| Testing | separate line | "part of development" | no |
| Deployment and server setup | included | no | no |
| Warranty period | yes | no | yes |
The empty cells jump out immediately. They explain most of the price gap.
Step 3. Find the missing items
The things most often forgotten or hidden in estimates:
- an admin panel to manage content and orders;
- integrations — payment providers, CRM, ERP, SMS, maps;
- testing and bug fixing after launch;
- infrastructure — servers, domain, SSL, backups;
- publishing the app to the stores;
- handover of code and documentation;
- support after launch.
Ask each vendor to state explicitly for every item: included, not included, or estimated separately.
Step 4. Bring them to equal terms
Once the gaps are found, ask vendors to estimate what is missing. Now you have three estimates for the same scope. Also compare:
- timelines and how they split into stages;
- payment terms — prepayment, payment by milestone;
- code ownership and repository access;
- change process — how new requirements are estimated.
Common mistakes
- Picking the cheapest estimate. A low price often means something is left out.
- Comparing hourly rates. What matters is the total cost of the result, not the price of an hour.
- Not asking about assumptions. Every estimate rests on assumptions — ask vendors to list them.
- Dismissing expensive estimates. Sometimes a vendor spotted a risk the others missed.