Comparison · verified July 2026
The Form 8621 Calculator is the deepest tool for one form. It just doesn't prepare the rest of your return.
This comparison treats Expat Tax Tools' Form 8621 Calculator as a specialist calculator rather than a full tax-return workflow. Its current export completeness, filing support, and pricing are not verifiable from the Atamatax codebase; confirm those details directly with the provider before deciding.
Who the Form 8621 Calculator is for
It is built for tax professionals and confident DIY filers who will assemble the 1040, FBAR, Form 8938 and treaty forms themselves and just want an audit-ready engine for the PFIC piece. If you file many Form 8621s across clients, its per-form pricing scales down further than anything else on the market.
Side-by-side
What you actually get
- Atamatax Winner
- A complete US expat return: 1040 with Forms 2555 / 1116 / 8938, the FBAR, and Form 8621 for each PFIC.
- the Form 8621 Calculator
- Form 8621 only — a calculator that produces the one form, not a return.
Form 8621 depth (§1291 / QEF / MTM)
- Atamatax
- §1291 worksheet with real IRS quarterly interest rates; QEF and mark-to-market elections.
- the Form 8621 Calculator Winner
- Dedicated multi-year PFIC engine, including transitional and expatriation rules — its whole product.
Price for a single PFIC
- Atamatax
- $299 flat — the entire return, Form 8621 included.
- the Form 8621 Calculator
- ≈$59.40/yr to use it + $74.95 per form pay-as-you-go — the 8621 only; you still prepare the return.
Per-form cost at volume (preparers)
- Atamatax
- Flat per-return pricing; not sold per form.
- the Form 8621 Calculator Winner
- Bundles fall to ~$10.95 per form at 500 — the cheapest per-form option anywhere.
FBAR + Form 8938
- Atamatax Winner
- Generated alongside the 1040 package.
- the Form 8621 Calculator
- Out of scope — not produced.
FEIE / FTC / treaty (2555 / 1116 / 8833)
- Atamatax Winner
- Handled as part of the return.
- the Form 8621 Calculator
- Out of scope — Form 8621 only.
Free draft before you pay
- Atamatax Winner
- On-screen draft is free; you pay to generate the PDF package.
- the Form 8621 Calculator
- Annual subscription required before you can use the calculator.
Filing / e-file
- Atamatax
- Draft PDF package; no integrated e-file or transmission.
- the Form 8621 Calculator
- Verify current PDF completeness and filing support with the provider.
The marked column indicates which product handles the feature more completely as of August 2026. We update this page when their offering changes — tell us if it's out of date.
Bottom line
Atamatax combines supported PFIC calculations and Form 8621 draft PDFs with mapped 1040, FBAR, Form 8938, and treaty worksheets in one paid package. You or your CPA still review and complete the forms and file outside Atamatax. Verify the other provider's current output and pricing directly.
Sources
Try it free
The on-screen draft is free. You pay when you generate the PDF package.
Start the wizard, see your real numbers, and decide from there.