Is it cheaper to build or buy software?

For standard, commodity capabilities such as accounting, CRM, help desk, or payroll, buying is almost always cheaper because the vendor spreads development, security, and support costs across thousands of customers. Building only becomes cost-competitive when no product fits your must-have requirements, when per-seat pricing at your scale exceeds the lifetime cost of owning the software, or when the capability is a genuine competitive differentiator. Compare total cost of ownership over three to five years, not launch cost against the first year's subscription.

How much does custom software maintenance cost per year?

A common planning rule is 15 to 20 percent of the initial build cost per year for maintenance: bug fixes, dependency and security updates, small enhancements, and keeping integrations working as the systems around it change. Over a five to seven year life, maintenance usually costs more in total than the original build. Teams that budget only for version one are the ones that end up with abandoned internal tools.

When does it make sense to build custom software?

Build when the capability is core to how you compete, when a real market evaluation shows no product covers your must-have requirements, or when your seat count is large enough that per-seat SaaS pricing exceeds the cost of owning the software. Building also assumes you can staff maintenance for years, not just the initial launch. If you cannot commit ongoing engineering time, do not build.

What is a hybrid build vs buy approach?

A hybrid approach buys a proven platform for the commodity foundation and builds only the differentiating layer on top. Common patterns include extending a purchased product through its API and webhook surface, using an iPaaS tool such as Zapier, Make, or Workato for integration glue, or using low-code platforms such as Retool or Airtable to assemble internal workflows without a full engineering build.

How do I compare total cost of ownership for build vs buy?

Model both paths over three to five years. For buying: subscription fees at your projected seat count, tier upgrades you will be forced into (SSO, audit logs, API limits are common triggers), implementation, integration work, admin time, and training. For building: discovery, development, infrastructure, security, QA, and ongoing maintenance at roughly 15 to 20 percent of build cost per year, plus the opportunity cost of engineers not working on your core product.

Build vs. Buy Software: How to Decide

The build vs. buy software decision is one of the highest-leverage calls a business makes. Choose well and you get capability that fits your needs at a sustainable cost. Choose poorly and you either bolt your operations onto a tool that fights your workflow, or you sink years of engineering time into rebuilding something you could have licensed for a fraction of the cost.

This guide gives you the actual math and the actual failure modes: how SaaS pricing really behaves as you grow, what custom development costs after launch (the part everyone underprices), which categories buying almost always wins, where building is genuinely justified, and a checklist you can run any candidate decision through.

What the build vs. buy decision really means

At its core, the choice is about where you spend your scarcest resources: money, time, and engineering attention. Buying means licensing a product built by a vendor who maintains it, supports it, and improves it across a large customer base. Building means owning the software outright, including every line of code, every bug, every security patch, and every future enhancement, for as long as you use it.

The decision is rarely all-or-nothing. Most organizations end up with a portfolio: buy the commodity systems, build the handful of things that genuinely set them apart, and stitch the two together. The skill is knowing which bucket each capability belongs in, and that requires understanding the cost shape of each path.

How SaaS pricing actually behaves

Almost all business SaaS is priced per user per month, billed annually, with three or four named tiers. The published entry tier for mainstream tools (CRM, project management, help desk) typically sits in the low tens of dollars per user per month, with mid tiers roughly double and top tiers double again. Always check the vendor’s current pricing page; these figures move.

The per-seat model has two properties that matter for the build vs. buy math:

Cost scales linearly with headcount, forever. At 15 seats a per-seat tool is trivially cheap compared to any build. At 500 seats, the same tool can cost more per year than a custom system costs to own. Run the multiplication at the headcount you expect in three years, not the headcount you have today.
Tier jumps are triggered by features you will eventually need. The most common forced upgrades: SSO and SAML (so routinely gated behind top tiers that buyers call it the SSO tax), audit logs, advanced permissions, API rate limits, sandbox environments, and priority support. Price the tier you will actually need at maturity, not the tier that gets you through the demo.

Some categories price on usage instead of seats: marketing platforms price per contact in the database, data tools price per row or per credit, and communications APIs price per message. Usage pricing grows with your business whether or not more humans use the tool, which makes long-range TCO harder to predict and worth modeling at two or three growth scenarios.

What custom development actually costs

Custom software has a different cost shape: heavy up front, then a long tail that most teams underestimate.

The build cost drivers, roughly in order of impact:

Scope and workflow complexity. A single-workflow internal tool is a different animal from a multi-role system with approvals, permissions, and reporting.
Integrations. Every external system the software must read from or write to (accounting, CRM, ERP, identity provider) adds real engineering and, more importantly, real maintenance, because those APIs change on someone else’s schedule.
Roles, permissions, and audit requirements. The moment different users may see different things, complexity jumps.
Compliance and security posture. Anything touching payment data, health data, or personally identifiable information at scale carries design, review, and testing overhead.

As honest ballparks at typical North American agency or contractor rates: a narrowly scoped internal tool with one workflow and no hard integrations often lands in the low to mid five figures for a first version. Anything with multiple roles, several integrations, and real reporting is normally a six-figure build. Treat these as orientation, not quotes; get two or three scoped proposals before you believe any number.

Then the multiplier. A common planning rule is 15 to 20 percent of the initial build cost per year for maintenance: dependency and security updates, bug fixes, small enhancements, and keeping integrations alive as the APIs around them change. Over a five to seven year life, maintenance usually costs more in total than the original build. This is the single number that flips most “building is cheaper” analyses once it is included.

Add the cost nobody invoices: every engineer maintaining an internal tool is an engineer not improving whatever your customers actually pay you for.

A worked TCO comparison

Model both paths over the same horizon. Here is the structure, with illustrative planning numbers (not vendor quotes) for a 40-person team over five years:

Cost line	Buy	Build
Year 1	40 seats at a planning rate of $30 per user per month, about $14,400, plus implementation and migration	Discovery plus build, assume $150,000 for a mid-complexity system
Years 2 to 5	Subscription at growing seat count, plus one likely tier upgrade	Maintenance at 15 to 20 percent of build cost per year, about $22,500 to $30,000 annually
Five-year total	Roughly $75,000 to $110,000 depending on growth and tier	Roughly $240,000 to $270,000
Also count	Admin time, training, integration fees, renewal increases	Infrastructure, security reviews, key-person risk, opportunity cost

At 40 seats, buying wins by a wide margin, which is the normal result for commodity software. Now rerun the same table at 800 seats: the buy column becomes roughly $290,000 per year in subscription alone, and the build column barely moves. Scale is the variable that changes the answer, which is why large enterprises build things that no 40-person company ever should.

When teams say building is cheaper, they usually priced version one against year one. The five-year totals are the honest comparison.

Where buying almost always wins

These categories are mature, competitive markets where vendors have invested decades and your requirements are, honestly, standard:

Accounting and payroll: QuickBooks, Xero, Gusto, ADP. Tax rules and compliance change constantly; you want a vendor absorbing that.
CRM software: HubSpot, Salesforce, Pipedrive, Zoho. The market covers everything from two-person shops to global enterprises.
Help desk and support: Zendesk, Freshdesk, Intercom, Help Scout.
HR and people ops: BambooHR, Rippling, Deel for global employment.
Email, docs, and office: Google Workspace or Microsoft 365. Nobody builds this.
Project management: Asana, monday.com, Jira, Basecamp.
E-signature, scheduling, expense management: DocuSign, Calendly, Ramp and similar. Thin, solved problems.

The pattern: heavy compliance burden, network effects, or decades of accumulated edge-case handling. A custom build in these categories starts years behind and never catches up.

Where building is genuinely justified

The software is your product, or the engine of it. You cannot differentiate on something competitors can also license.
Pricing, quoting, or matching logic specific to your economics. A configure-price-quote engine that encodes how you actually make money, or marketplace matching logic that is the business itself.
Proprietary data pipelines and models. When your advantage is what you do with data nobody else has, the processing layer is core, not commodity.
Genuine market gaps after a real evaluation. Sometimes the honest conclusion of a serious selection process is that nothing covers the must-haves. Verify this by actually running the process, not by assuming it.
Per-seat math broken by scale. A tool everyone in a several-thousand-person company touches occasionally is exactly where per-seat pricing is most punishing and a build most defensible.
Integration glue beyond what iPaaS covers. Most connection work should go to Zapier, Make, or Workato first. Build the glue only when the volume, latency, or logic exceeds what those platforms handle.

The failure modes of buying

Buying is the right default, but it fails in predictable ways. Go in with eyes open:

Per-seat creep. The tool that cost $500 a month at signing costs $4,000 a month three years later through seat growth, tier upgrades, and renewal increases. Annual price escalators of 5 to 10 percent at renewal are common in enterprise contracts unless you negotiate a cap.
Shelfware. Licenses bought in bulk, used by a fraction of the team. Audit actual usage before every renewal.
Roadmap dependence. The feature you need sits on the vendor’s roadmap indefinitely, and you have no lever to pull.
Acquisition and sunset risk. Products get acquired and merged, or quietly deprecated. Vendor stability belongs in your evaluation, not just features.
Lock-in you discover at exit. Cheap to enter is not cheap to leave. Check data export, in a usable format, before you sign, not when you want out.
Configuration sprawl. Five years of ad hoc admin changes can make a bought tool as fragile and undocumented as any legacy custom system.

The failure modes of building

Version-one optimism. The launch estimate is treated as the total cost. Maintenance, the larger half of lifetime cost, never gets budgeted.
Key-person risk. The one engineer who understands the system leaves, and the tool ossifies because nobody dares touch it.
Maintenance starvation. Internal tools lose every prioritization fight against customer-facing work, so they decay: dependencies age, integrations break, security patches lag.
No product owner. Bought software has a vendor listening to thousands of customers. Internal software often has nobody whose job is making it better, so it fits the workflow of the year it was built, forever.
The resume project. Engineers enjoy building. Enthusiasm for the work is not a business case for the work.
Rebuild churn. Underscoped v1 leads to a rewrite, which leads to the organization losing faith and buying anyway, having paid for both paths.

Hybrid approaches: often the smart answer

Two hybrid patterns capture most of the upside of both paths:

Buy and extend. Adopt a proven platform for the foundation, then shape the differentiating layer through its configuration, API, and webhooks. You get the vendor’s security and maintenance while owning only the thin slice that makes you different.
Low-code and iPaaS for the middle. Retool and Airtable for internal apps, Zapier, Make, or Workato for integration glue. These close the gaps between bought tools at a fraction of custom-build cost, with the honest caveat that complex logic in these platforms eventually becomes its own maintenance burden.

A common winning pattern: buy the commodity systems, use platform extensibility and iPaaS for the middle layer, and reserve true custom development for the narrow slice that is genuinely your competitive edge.

The decision checklist

Run the candidate capability through these ten questions. Count the yes answers.

Is this capability table stakes rather than how you win deals?
Do your requirements look mostly like everyone else’s in your industry, if you are honest?
Did a real market scan (not a casual one) find at least one product covering every must-have?
Does the business need this live within a quarter?
At your three-year projected seat count, is the subscription still clearly cheaper than build cost plus 15 to 20 percent of build cost per year in maintenance?
Would a build compete with customer-facing work for the same engineers?
If the engineer who built it left, would you struggle to maintain it?
Does the category carry compliance weight (tax, payroll, payments, health data) a vendor already absorbs?
Can you live with the vendor controlling the roadmap?
Is exportable data at exit confirmed, making lock-in tolerable?

Seven or more yes answers: buy, and spend your energy on selection and adoption. Four to six: look hard at hybrid. Three or fewer, especially if the no answers cluster on differentiation and market fit: a build or a buy-and-extend deserves a scoped proposal and a real TCO model before you commit either way.

Making the call

Most decision-makers land on buy for the majority of their stack and reserve building for the few capabilities that are truly core. The math above tells you which is which before you commit budget, and the failure-mode lists tell you what to guard against on whichever path you take.

If you decide to buy and want to skip weeks of demos, SoftwareSelect provides free, unbiased shortlists from real advisors, matched to the must-have and differentiating requirements you’ve defined. You can get free advice, browse software categories to see your options, or explore specific areas like project management software to benchmark what the market already offers before you consider a build.