What the subscription costs over three years, not this month
Vendor pricing pages quote a per-seat number because a per-seat number looks small. The bill arrives as seats plus overage plus a term commitment, and the alternative arrives as a hosting line plus somebody's hours. These calculators put both on the same 36-month axis, then tell you which VPS the replacement actually needs.
Cost calculators
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E-signature TCO
Docusign alternative TCO
Seats, envelope overage, SMTP and admin hours over 36 months, plus the VPS spec a Documenso or DocuSeal Compose stack needs.
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PDF tooling TCO
Acrobat alternative TCO
Split seats into heavy desktop editors and browser users, then price buyout licences plus a Stirling-PDF host over 36 months.
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PaaS vs self-host
Vercel vs Coolify TCO
Seats plus egress overage against a Coolify stack on a Hetzner-class host, including the traffic allowance and the maintenance hours.
Open calculator
Three things make a subscription renewal hard to argue with: the price is quoted per seat, the invoice includes meters nobody modelled, and the alternative is priced in a currency the finance team is not used to - a monthly hosting charge and a fraction of an engineer's attention. This site converts the second into the first. Every calculator here returns a 36-month total for both sides, the net difference, and the exact machine the self-hosted option needs to run on.
None of it requires an account, and none of the numbers are hidden behind an email form. Each page prints the formula it uses, publishes the price it assumed, and recomputes its own table at build time so a stale row cannot survive a deploy.
How to read a result
The headline is the net 36-month difference, but the two numbers that decide whether to act are underneath it. The first is the run rate: a self-hosted stack that costs $74 a month is easy to authorise, and one that costs $900 a month in labour is a staffing decision wearing a cost-cutting hat. The second is the hardware tier, because a migration plan that assumes a $5 instance will run a Java application with an OCR pipeline is not a plan.
What these tools deliberately do not do
They do not model discounts you have not been offered, they do not assume you will negotiate 40% off at renewal, and they do not invent enterprise pricing for tiers that are quote-only. Where a vendor publishes a price, that price is the default; where the price depends on your contract, it is an input you set. Where a self-hosted stack has a documented memory floor, the floor is enforced rather than rounded down to make the comparison look better.
Where the numbers come from
Vendor prices come from the product's own public pricing page, with the plan name and the billing basis recorded next to the formula. Hardware prices come from the published list rates of mainstream KVM cloud instances. Open-source memory requirements come from the project's own documentation and Compose files. The method page lists the sources, the assumptions and the cases where you should not trust the output.