What's the real cost of building a SaaS in 2026?

The number you get from most agencies is the easy part. The total cost is bigger and most founders only see it after they have signed the wire. Let us break it down for a realistic B2B SaaS: multi-tenant, Stripe billing, basic admin, dashboard, email transactions, maybe an integration with one or two third-party services. Build cost (the part people quote you): Lean MVP version (single tenant, basic features) runs $5K to $30K and ships in one to four weeks. Standard MVP (multi-tenant, billing, admin) is $30K to $80K and takes six to fourteen weeks. Production-ready v1 (compliance-aware, error handling, real testing) is $80K to $200K and takes three to six months. If someone quotes you $5K for a SaaS with all the bells and whistles, they are either offshore juniors or they are underestimating dramatically. The real bill always comes later. Recurring infrastructure costs (post-launch): Hosting on Vercel or similar runs $20 to $200 per month depending on traffic. Managed Postgres is $25 to $300 per month for small to medium load. Auth (Clerk or similar) is $0 to $100 per month at MVP scale and scales with users. Email through Resend or Postmark is $20 to $100 per month. Payment processing through Stripe takes 2.9% plus $0.30 per transaction. Error monitoring through Sentry is $26 to $100 per month. Analytics through PostHog or Plausible is $0 to $50 per month. So before you have customers, that is roughly $150 to $700 per month just to keep the lights on. With customers it scales up. Hidden costs nobody tells you about: Compliance and legal. A SOC2 starter audit runs $15K to $30K. GDPR DPA templates if you sell into the EU. Privacy policy and terms of service drafted properly. Customer support. Even if it is just you answering emails, that is your time. Build a help center early. Payment refunds and disputes. Stripe disputes cost $15 each. Plan for them. Bug fixes and small features after launch. Budget 30% of your build cost per quarter for the first year. Nobody ships a perfect v1. Marketing site, content, SEO. Separate from the SaaS itself. Easily another $5K to $20K. So a $50K build is often actually a $80K to $120K first-year total once you add infrastructure, compliance, post-launch fixes, and the marketing site. What founders underestimate most: Time-to-revenue. Building takes weeks. Distribution takes months. The CTO tax. If you are non-technical and the agency disappears, you will pay 2x to bring in someone to maintain what is there. Re-platforming. If you pick the wrong stack for scale, redoing it later costs more than the original build. A reasonable budget for "ship a SaaS, get to first 10 paying customers" in 2026 is $80K to $150K all-in for year one. Less than that, and you are cutting something important (probably support or compliance). More than that, and you are probably over-engineering before you know what to optimize. The cheapest part of a SaaS is the first build. The expensive part is iterating after you launch. Plan for both.