# Build vs buy decision tool

Free, vendor-neutral build vs buy tool. Compare buying software, configuring a low-code platform and building custom on a weighted scorecard and a discounted three-year total cost of ownership, with the method and sources shown.

URL: https://smallbaydigital.com/tools/build-vs-buy/  
Updated: 28 October 2026  
Publisher: SBD (smallbaydigital.com). Free, runs in the browser, nothing entered is stored on a server.

## In short

Buy when the capability is not what sets you apart and a product fits most of the need. Configure a platform when the process is yours but the parts are standard. Build when the software is the difference customers pay for, you can maintain it, and a three-year cost comparison still favours it after counting upkeep, your own team’s time and the months before it delivers value.

## How to use it

1. **Describe the three options.** Enter the one-time cost, seats, subscriptions, upkeep and months to value for buying, configuring a platform and building.
2. **Weight the criteria.** Set how much differentiation, fit, cost, time to value, capability, control and exit matter to you.
3. **Score each option.** Rate each option from 1 to 5 on each criterion, with evidence from demos, quotes and references.
4. **Read cost and score together.** Compare the weighted score with the discounted three-year cost and the month each option starts delivering.
5. **Check the swing criteria.** See which criteria decide the result, and test those claims with the vendor or a prototype before signing.

## Worked example

A 40-person wholesaler needs order intake. Buying a product costs $3,000 to set up plus 12 seats at $35 a month. Configuring a low-code platform costs $9,000 plus $300 a month. Building custom costs $30,000 plus $150 a month in hosting. Upkeep is 20% a year for the two built options, and the team spends 2, 3 and 4 hours a month on each at the $46.15 loaded rate. Over three years at a 10% discount rate, buying costs about $19,000, configuring about $27,000 and building about $56,000. On the default weights, configuring scores 76, buying 73 and building 72: a close call, so the tool flags differentiation, fit, cost and exit as the criteria to test before deciding.

## Terms

- **Total cost of ownership (TCO):** Every cost of an option over its life: set-up, licences, seats, hosting, your own team’s time and upkeep, not just the price.
- **Configure:** Building on a low-code platform or automation tool: your process, standard parts, faster than custom and with less lock-in than a closed product.
- **Time to value:** Months from decision until the option is doing useful work. Value lost while waiting is a real cost.
- **Differentiation:** Whether the capability is part of why customers choose you. Differentiating software is a candidate to own; commodity software is a candidate to buy.
- **Lock-in:** How hard and costly it would be to leave: data export, contract terms, proprietary logic and retraining.
- **Weighted score:** Each criterion score times its weight, summed and scaled to 100.

## Sources

- ISO/IEC, [ISO/IEC 25010:2023, product quality model](https://committee.iso.org/standard/78176.html). Nine product quality characteristics: functional suitability, performance efficiency, compatibility, interaction capability, reliability, security, maintainability, flexibility and safety. Used for: Fit and control criteria.
- Forrester, [Total Economic Impact methodology](https://www.forrester.com/policies/tei/). Benefits, costs and risk, discounted over the analysis period; most published studies use three years at 10%. Used for: Three-year discounted cost comparison.
- Practitioner frameworks, Build vs buy decision scorecards. Published decision frameworks agree on differentiation, fit, total cost, time to value, in-house capability, compliance and exit. No audited benchmark sets the weights, so the defaults are shown and editable. Used for: The seven criteria.
- Practitioner guidance, Maintenance planning figures. 15 to 22% of build cost a year for stable systems, 30 to 40% where integrations or prompts change often. Used for: Default upkeep for building and configuring.

## FAQ

### When should a company build software instead of buying it?

When the capability is part of why customers choose you, no product fits the core of the need, you have or can hire the people to run it, and a three-year cost comparison still favours building after counting upkeep, internal time and the months before it delivers value.

### What is the middle option between building and buying?

Configuring a low-code platform or automation tool such as Airtable, Retool or n8n. You get your own process on standard parts, usually faster and cheaper than custom, with less lock-in than a closed product. It suits most internal operations software.

### What costs do build vs buy comparisons usually miss?

Your own team’s time on selection, implementation and testing; upkeep when connected systems change; seats that grow with headcount; migration and exit costs; and the value lost in the months before a custom build is ready.

### How should the criteria be weighted?

Weight differentiation and fit highest when the software touches what customers buy; weight cost and time to value highest for back-office tools. Agree the weights before scoring options, so the weights cannot be bent to fit a favourite.