Method, sources, and what this site will not tell you
A cost model is only useful if you can see its assumptions. This page lists the pricing sources behind each calculator, the hardware ladder used for self-hosted sizing, how the tables are verified on every build, and the situations where the honest answer is to keep paying the vendor.
What each calculator assumes
Every page runs the same three-stage model, and the stages are worth stating plainly because they are where a comparison usually goes wrong.
- Price the vendor as it actually bills. Not the headline seat rate, but the seat rate applied to the seats you must buy, plus every meter that grows with usage - envelope overage, bandwidth overage, per-user storage. Where the published plan has an included allowance, that allowance is applied before any overage is charged.
- Price the replacement as it actually runs. Compute the hardware from the stack's documented memory floor plus a per-user allowance plus 25% headroom, pick the smallest mainstream tier that satisfies both memory and core count, and add the lines people forget: block storage past the included disk, an off-site backup copy, transactional email, and the hours somebody spends owning it.
- Put both on 36 months and show the difference. Three years is long enough to outlast a one-off licence and short enough that hardware refresh cycles do not distort the answer.
Where the prices come from
| Page | Vendor basis | Self-hosted basis |
|---|---|---|
| Docusign alternative | Standard $25/user/mo on annual billing, 100 envelopes per user per year pooled; Business Pro $40; Personal $10 with 5 envelopes a month. Overage is sold in packs, so $4.00 per envelope is a planning figure rather than a published line. | Documenso or DocuSeal Docker Compose: app container, PostgreSQL, S3-compatible storage, reverse proxy. 2 GB memory floor plus 0.08 GB per seat. |
| Acrobat alternative | Acrobat Pro single-app subscription on annual billing paid monthly. Adobe prices by region and agreement, so the seat price is an input. | Stirling-PDF container (Java, LibreOffice, Tesseract) with a 4 GB floor, plus buyout desktop licences for heavy users at $100-200 one-off. |
| Vercel vs Coolify | Pro at $20/user/mo on annual billing with 1 TB of included fast data transfer; on-demand bandwidth at $0.15 per GB, about $150 per TB. | Coolify control plane plus one app container per service on a mainstream KVM instance with 4-20 TB of included egress; egress above 10 TB charged at $2 per TB. |
The hardware ladder
Sizing is not a lookup on a provider's price list, it is a requirement expressed in memory and cores and then matched to the cheapest tier that satisfies it. The ladder used across the site is 2 vCPU / 4 GB at $8 a month, 4/8 at $16, 4/16 at $28, 8/32 at $56 and 16/64 at $112. These are representative list prices for shared-vCPU KVM instances across the mainstream providers, not a quote from any single one.
Two rules sit on top of the ladder. Memory is the working set multiplied by 1.25, which covers container overhead and the burst that happens during a PDF render or a build. Cores are one per 25 interactive seats plus one for the operating system and the proxy. When a requirement exceeds the top of the ladder, the model buys a second host rather than pretending a bigger box exists - which is why the sheet occasionally reports two servers instead of one.
How the tables are verified
Every comparison table on this site is generated from the same functions the calculator runs, and those functions are covered by unit tests. Before the site builds, a script re-runs each table row through the published formula and compares it to the value in the table; if a row drifts, the build fails and nothing is published. A second check re-derives the hardware tier and the labour line for every row, so a table cannot quietly disagree with the calculator above it.
What that machinery cannot catch is a wrong assumption at the top - for example if a vendor changes its plan structure and the documented allowance in the note above is no longer accurate. That part is checked by hand when a page is written and re-checked when it is revised. If you find a price that has moved, the date on the page tells you how old the figure is.
What this site does not do
- No invented enterprise pricing. Where a vendor only sells through sales, the page says so and the price stays an input. A number nobody can verify is worse than no number.
- No discount assumptions. The model uses list prices. If you have negotiated 30% off, enter the price you actually pay - the calculator takes it.
- No migration labour beyond a fixed allowance. Four hours for a first deployment, recurring hours as an input. Real migrations have data export, user training and a parallel-run period that this model does not attempt to price.
- No compliance advice. Qualified signatures, FedRAMP, 21 CFR Part 11 and records retention are legal questions. The pages flag where self-hosting moves an obligation onto you rather than discharging it.
- No affiliate links in the results. The hardware recommendations are described by specification, not by vendor referral. If that ever changes, the page will say so in the first paragraph rather than in the footer.
When the subscription is cheaper
Three honest cases. First, when the compliance requirement is an authorisation rather than a feature - a FedRAMP boundary or a qualified trust service is not a container you can pull. Second, when the load is genuinely latency-sensitive and global, because one VPS in one region is not an edge network and no amount of savings fixes a 400 ms round trip. Third, when nobody on the team owns the system: an unpatched public endpoint is a liability, and the subscription is buying operational competence as much as software.
The calculators are built to show those cases rather than hide them. Set the admin hours to four a month and watch the net saving collapse. Set the heavy-user share to 100% and watch the hybrid stack lose to the subscription. That is the tool working correctly.
Independent third-party estimate. SelfHostTCO is not affiliated with, endorsed by, sponsored by or otherwise connected to Docusign Inc., Adobe Inc., Vercel Inc., Hetzner, Hostinger, Vultr, DigitalOcean, Documenso, DocuSeal, Stirling-PDF or Coolify. Product and company names are trademarks of their respective owners and are used here only to identify what is being compared. All prices are public list prices captured on the date shown on each page and change without notice; verify against the vendor's own pricing page and your contract before making a purchasing decision. Nothing on this site is financial, legal or compliance advice.
Questions, corrections or a price that has moved: the fastest route is to check the source link on the page in question, then compare it to the date at the top. Every page carries one.