Build vs. Buy

Should you pay for a SaaS subscription or build your own? See the numbers.

• Saas: SaaS option

• Saas Monthly: Monthly subscription

• Saas Monthly Suffix: / mo

• Saas Growth: Expected yearly price increase

• Custom: Custom build option

• Build Cost: Estimated build cost

• Preset Small: Small

• Preset Small Hint: Simple tool, ~3-4 weeks

• Preset Medium: Medium

• Preset Medium Hint: Real product, ~6-8 weeks

• Preset Large: Large

• Preset Large Hint: Complex platform, ~3-6 months

• Preset Aria: Build cost preset

• Custom Amount: Or enter a custom amount

• Maintenance: Yearly maintenance (% of build cost)

• Horizon: Time horizon

• Horizon Aria: Time horizon in years

• Year One: 1 year

• Saas Label: Subscribe (SaaS)

• Build Label: Build custom

• Build Saves: Building saves

• Buy Doesnt: Subscribing saves

• Never Break Even: Even after 30 years, subscribing stays cheaper. Building only makes sense here if you need something SaaS can't give you: control, integrations, or no per-user fees at scale.

• Want Built: Want this answered for real?

• Cta Title: Want a tool like this, or the full app behind the answer, built for you and ready to use?

• Real Quote: Get a real quote

• Disclaimer: Estimates only. Real numbers depend on your team, your data, and the SaaS lock-in cost of switching later. Use this as a starting point, not a contract.

• About Title: Build vs. buy, the math behind the decision

About

• Every founder hits the same fork in the road: pay for a SaaS subscription forever, or invest in a custom software build you actually own. This free build vs. buy calculator runs the total cost of ownership for both options over your chosen time horizon, 1, 3 or 5 years, and shows in plain numbers which one wins, by how much, and exactly when the break-even point hits.

• Most build-vs-buy decisions go sideways because people compare a one-time build cost to a single month of SaaS, ignore yearly price hikes, and forget about maintenance. This tool fixes all three. It compounds the SaaS subscription with realistic annual price increases, adds a maintenance percentage on top of the build cost, and projects total cost month by month so the break-even line is visible, not theoretical.

• Use it to pressure-test internal proposals, defend a budget request, or sanity-check the next 'we'll just buy it' or 'we'll just build it' decision before it costs you. The math is the same TCO model used in software procurement, stripped down to the three numbers that actually matter: monthly subscription, build cost, and how long you plan to keep using it.

• Faq Title: Frequently asked questions

Faq

When does building custom software make more sense than buying SaaS?

Building usually wins when you have a clear, unique workflow that off-the-shelf SaaS forces you to bend; when per-seat SaaS pricing scales painfully as you add users; when you need to own your data, integrate deeply with internal systems, or avoid vendor lock-in. Run the calculator with your real numbers. If building pays itself back inside your time horizon, it's usually the right call.

When should I just buy SaaS instead?

Buy SaaS when the problem is generic (CRM, accounting, email marketing), the SaaS solves it well, and the monthly cost stays under a few thousand euros for the foreseeable future. Building a worse version of an excellent SaaS is one of the most expensive mistakes a small team can make.

What is total cost of ownership (TCO) for software?

TCO is the full cost of using a piece of software over its lifetime, not just the sticker price. For SaaS, it's every monthly invoice plus future price hikes. For a custom build, it's the upfront build cost plus yearly maintenance, typically 10–20% of the original build per year for security patches, dependency updates, and small feature work.

What yearly maintenance percentage should I use?

Use 10% if your build is small and stable, 15% for an average production web app, and 20%+ if it's complex or business-critical. Maintenance covers framework upgrades, security patches, hosting changes, and small fixes, not new features. Treat it like insurance: low if you skip it, expensive when it breaks.

What annual SaaS price increase should I expect?

B2B SaaS typically raises prices 5–15% per year, with bigger jumps when you cross seat tiers or add 'enterprise' features. Many vendors front-load the discount in year one and quietly raise it on renewal. The growth slider in the calculator lets you model that explicitly.

Is build vs. buy only about money?

No, but money is the part you can model cleanly. Beyond cost, weigh control, vendor lock-in, integration depth, and how strategic the workflow is to your business. If the SaaS goes away, raises prices 3×, or refuses to add the integration you need, what's the cost to your business? Add a buffer to the 'build' side for that optionality.

Using the interactive tool

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