Build vs. Buy Calculator (Software TCO)
Print Analysis| Net Financial Savings | $0 |
| Year 1 Expense Comparison | Build: $0 vs Buy: $0 |
Every time a company needs a new piece of technology, management faces the ultimate IT dilemma: Do we hire engineers to build a custom solution from scratch, or do we pay a monthly subscription for an off-the-shelf software product? While building your own software gives you absolute control, it comes with massive hidden maintenance costs. While buying a SaaS product gets you running immediately, you are forced to pay licensing fees forever.
Our free online Build vs. Buy Calculator allows CTOs, IT Directors, and Operations Managers to instantly compare the Total Cost of Ownership (TCO) between custom development and commercial software. By mapping out the upfront costs, ongoing maintenance, and monthly licensing fees over a multi-year period, you can make a data-driven decision that protects your company’s bottom line.
How to Use the Build vs. Buy Calculator
To accurately run this calculation, you must forecast costs over a standard 3-year or 5-year lifecycle. Here is exactly how to input your data for a flawless TCO comparison:
- Step 1: Custom Build Costs. Enter the estimated number of engineering hours required, multiplied by your developers’ hourly rates. Be sure to include the ongoing annual maintenance cost (usually 15% to 20% of the initial build cost).
- Step 2: Commercial “Buy” Costs. Enter the monthly or annual licensing fee for the SaaS product, multiplied by the number of employee seats you need.
- Step 3: Implementation & Onboarding. Enter the upfront fees charged by the SaaS vendor to set up your account, migrate your old data, and train your staff.
The Hidden Costs Matrix (What Most Managers Forget)
When running a Build vs. Buy analysis, junior managers often only compare the initial development cost against the first year of SaaS licensing. This is a catastrophic mistake. You must account for the hidden, long-term costs of both paths.
| The Path | The Obvious Cost | The Hidden Long-Term Costs |
|---|---|---|
| Option A: Build It | Developer salaries and cloud hosting bills. | Technical Debt & Maintenance: Software is never “finished.” You will spend tens of thousands of dollars every year fixing bugs, patching security flaws, and updating the code to work with new operating systems. |
| Option B: Buy It | Monthly/Annual subscription fees. | Vendor Lock-in & Seat Scaling: If your company doubles in size, your SaaS bill doubles immediately because you pay per seat. Furthermore, commercial vendors routinely raise their prices by 10% every year. |
Beyond the Math: The Strategic Decision Matrix
Sometimes, the math tells you to Buy, but the business strategy dictates you must Build. Even if custom software is more expensive, there are certain scenarios where it is absolutely mandatory for the survival of the business.
| The Scenario | The Recommendation | Why? (Strategic Rationale) |
|---|---|---|
| The software is your Core IP. | BUILD IT | If the software is the actual product your customers are paying for (your competitive advantage), you must own it. You cannot outsource your core business logic to a third party. |
| The software is a Commodity. | BUY IT | Things like HR payroll, employee email, and basic CRMs do not make your company unique. Do not waste expensive engineering talent building a clone of something that already exists. |
| Time to Market is Critical. | BUY IT | If you need a solution running by next week to satisfy a massive client contract, building it is impossible. Buying an off-the-shelf product is the only way to meet the deadline. |
Real-World TCO Example: The Custom CRM
To truly understand how to calculate Total Cost of Ownership (TCO), let’s look at a practical example. Your company needs a new Customer Relationship Manager (CRM). You are comparing a 3-year TCO between building a custom portal versus buying Salesforce.
The “Build” Option: Your lead engineer estimates it will take 800 hours at $100/hr. The upfront build cost is $80,000. Maintenance will cost roughly $15,000 per year for Year 2 and Year 3. Your 3-year TCO for building is exactly $110,000.
The “Buy” Option: A commercial CRM costs $30,000 per year for your team size. The vendor charges a one-time $5,000 onboarding fee. Over 3 years, you pay $90,000 in licenses plus the $5,000 setup fee. Your 3-year TCO for buying is exactly $95,000.
In this scenario, buying the commercial software saves the company $15,000 over three years, and the software is available to use on day one instead of waiting 6 months for developers to build it.
If you decide to build the software, you must ensure it actually generates a return on your engineering investment. Check your financial health using our ROI Calculator. If you are a startup making this decision and want to see how an $80,000 custom build will drain your bank account, use our Burn Rate Calculator.
Frequently Asked Questions (FAQ)
What is “Opportunity Cost” in a Build vs. Buy decision?
Opportunity cost is the financial value of what your engineers could have been working on if they weren’t building this software. If your top developers spend 6 months building an internal HR tool, that means they spent 6 months not building new, revenue-generating features for your customers. In tech, opportunity cost is often the most expensive part of building.
How much should I estimate for annual software maintenance?
As a general industry rule of thumb, annual software maintenance costs between 15% and 20% of the original development cost. If you spend $100,000 building a custom application, you should budget $15,000 to $20,000 every single year just to fix bugs, manage server costs, and keep it running smoothly.
What is “Vendor Lock-in”?
Vendor lock-in occurs when you buy a SaaS product and your company becomes so heavily dependent on it that switching to a competitor becomes virtually impossible. The vendor knows it would cost you too much time and money to migrate your data, so they can aggressively raise your subscription prices every year.
Does “Buy” always mean a monthly SaaS subscription?
Not always, but almost exclusively in the modern era. Historically, companies would “buy” software by paying a massive one-time perpetual license fee and installing it on their own on-premise servers. Today, 99% of commercial software vendors have moved to cloud-based, recurring monthly SaaS subscriptions.
Why do companies ever choose to build commodity software?
Usually, it is due to extreme security, privacy, or compliance requirements. For example, a hospital might choose to build its own internal communication app rather than using Slack or Microsoft Teams, simply because they need absolute, on-premise control over sensitive patient HIPAA data.
What is the typical timeframe for a TCO analysis?
Most CTOs and finance departments use a 3-year or 5-year timeframe for Total Cost of Ownership (TCO) calculations. Analyzing less than 3 years artificially favors the “Buy” option (because build costs are heavy upfront). Analyzing more than 5 years is pointless, as the technology landscape changes too rapidly to predict.