In-house development or off-the-shelf software: Comparing costs correctly
A fair cost comparison includes implementation, customization, licenses, operation, and vendor switching. Only comparable timeframes provide a reliable basis for decision-making.
For management and product managers, when comparing in-house development and standard software, "identical target scope" and "complete capacity costs" are crucial. "List price focus" serves as a cross-check.
Published: 3 min read · Author: Sebastian Geier
How can the total costs of in-house development and standard software be fairly compared?
The comparison begins with a shared target scope and clear quality requirements. For standard software, licensing, implementation, configuration, integration, and vendor switching are included; for in-house development, product work, operation, security, knowledge, and maintenance are considered. Uncertain values are presented as ranges to prevent false precision from distorting the decision.
Counter-example: "List price focus"
A standard solution has a low list price but requires ongoing external custom configuration and several add-on modules. In-house development would be more expensive initially but could limit the scope to a stable core. Only by considering internal support, change requirements, and replacement costs will it become clear which option is viable in the long run.
End-of-life options
Control signal
Signal 1
Deviation of actual internal and external lifecycle costs from the chosen decision scenario.
Control signal
Signal 2
Proportion of ongoing costs that cannot be directly attributed to a utilized business capability.
Total capacity costs
Define a common target scope, load assumptions, and quality limits for both options.
Capture cost blocks for implementation, usage, modification, operation, and exit, including bandwidths and sources.
Compare scenarios for stable, growing, and changing businesses and highlight sensitive assumptions.
Identical target scope
Identical target scope Both options are calculated against the same mandatory capabilities, quality thresholds, and deliberately excluded functions.
Total capacity costs Internal product, operational, and specialist work is captured even if it is not invoiced externally.
End-of-life options Upgrade, continued operation, replacement, and migration are considered as possible paths with their respective costs.
List price focus
List price focus Modules, usage jumps, consulting, and internal administration remain outside the purchase invoice.
Project Price Focus – The in-house solution is calculated after completion without ongoing product and security responsibility.
Unequal Performance Threshold – A broad standard suite is compared to a narrow in-house development without disclosing unused or missing capabilities.
Related questions and next steps
Connect existing tools or build a central core? answers the next practical question: When are connected tools sufficient, and when does the organization need a central core system?
When a complete rebuild is more cost-effective than further repairs continues this line of thought with another question: When is a complete rebuild more cost-effective than further repairs?
If you want to put "In-house Development vs. Standard Software" into practice, you can refer to Robust Website Systems . The focus there is on "sourcing, costs, and exit" and "identical scope of objectives."
Conclusion: In-house development versus standard software are cost-effective
A fair comparison reveals hidden work and future flexibility. The more economical option is the one whose overall responsibility aligns with the needs and available organizational resources.
Sources and Further Information
The primary sources define the technical framework for "comparing in-house development with standard software."
Choosing Technology: An Introduction – GOV.UK Service ManualOfficial guideline on build vs. buy, total cost, data control, vendor lock-in, prototyping, and modifiability.
11. Choose the right tools and technology – GOV.UK Service ManualOfficial service standard on cost-effective technology selection, total cost of ownership, and the ability to change direction later.
Key Thesis
Both options are compared over the same lifecycle and with the same performance limits. In addition to money, internal capacity, dependencies, and the costs of later modifications are taken into account.
What This Is Not About
License price and initial development costs do not constitute a fair cost comparison. Standard software is not maintenance-free, and in-house development consists of more than just the initial project budget.
What it's about
Both approaches are compared over the same period, with the same performance limits, and with realistic usage scenarios. Internal capacity, customization, operation, switching, and missed opportunities must be included in the calculation.
Platform strategy & build vs. buy
Identify vendor lock-in early and assess its economic impact.
As a separate step in the "Comparing In-House Development vs. Standard Software" process, consider the question: How can vendor lock-in be economically assessed before choosing a platform?
Platform strategy & build vs. buy
Comparing Platforms Based on Capabilities Instead of Feature Lists
Supplementing the "Comparing In-House Development vs. Standard Software" process with a separate decision: How can platforms be compared based on required capabilities rather than lengthy feature lists?
Insights Overview
All VELUNO Insights at a Glance
Further analyses on Website Systems, digital visibility, and robust working models.
Complete Capacity Costs: First Control Step
Before investment approval, a common cost structure should be established to ensure both options are on an equal footing. An independent lifecycle cost analysis can reveal particularly sensitive assumptions and exit costs.