DeterminedAI vs Quaderno 2026: SaaS VAT Software Compared

Quaderno has been one of the most-used VAT calculation tools for indie SaaS since 2014. It's clean, Stripe-first, and does exactly what it says: calculates VAT and sales tax at the point of sale, generates invoices, and produces reports. For SaaS companies that want a calculation-and-reporting layer and nothing more, it's a strong pick. For SaaS that need the return itself worked out, not just the math, the gap between Quaderno and a fuller platform like DeterminedAI shows up quickly. This guide is honest about where each product wins and where the boundaries are.

1. Where each product comes from

Quaderno

Founded in 2014, headquartered in Spain. Built specifically for digital businesses (SaaS, e-commerce, info products) selling cross-border. Strong reputation in the indie SaaS and Stripe-first communities. The product surface has stayed remarkably consistent: calculate the right tax at point of sale, generate compliant invoices, surface reports that customers (or their accountants) submit to tax authorities. The team made a deliberate choice not to extend into registration or filing, treating those as accountant work that lives outside the software.

DeterminedAI

Built around a different bet: SaaS finance teams want the entire compliance lifecycle in one product, not just the calculation layer. The defining capabilities are AI-driven transaction characterisation (instead of static rule-table mapping), return workings and draft returns generated from your transaction uploads, country-by-country nonresident regimes for 70+ jurisdictions, and audit-defensible determination logs. The product is heavier than Quaderno because it does more.

2. Coverage and capability comparison

Where Quaderno wins

• Stripe-native polish. Quaderno was Stripe-first from the start, and the connector reflects a decade of refinement. Reverse-charge handling, invoice formatting, customer-facing receipts, multi-currency display all work with minimal configuration.
• Onboarding speed. A new Quaderno account can be calculating VAT correctly within a few hours. The product surface is small enough to fit in your head; the configuration choices are constrained.
• Lower starting price. Quaderno's Starter tier (around $49/month) is cheaper than DeterminedAI's Compliance subscription ($99/jurisdiction/month) for a single-jurisdiction footprint. For SaaS doing only calculation and EU OSS reporting at very small volumes, Quaderno is the more cost-efficient pick.
• Customer-facing invoice UX. Quaderno's auto-generated invoices look clean and are sent straight to customers from the platform. DeterminedAI focuses more on the API/audit-trail layer and less on customer-visible invoice presentation.

Where DeterminedAI wins

• OSS return workings and draft returns. Quaderno produces submission-ready data; DeterminedAI computes the quarterly OSS return box by box from your uploads, with an Excel workings file showing each backing transaction and a draft return on the form structure, AI-reviewed before you file.
• Country-by-country nonresident regimes. 70+ country-specific guides with bespoke regime handling. Quaderno covers the common jurisdictions but doesn't go as deep on India OIDAR, Saudi Arabia ZATCA, GCC nonresident, Brazil tax reform, Eastern European regimes.
• AI-driven determination. Each transaction returns the rate plus the rule applied, the article of the relevant directive, and the chain of reasoning. Quaderno uses a static rule-table approach (same family as Avalara, Vertex), which works well at the calculation layer but gives less audit trail.
• Conversational Tax Assistant. Ask any VAT/GST question in plain language (how to treat a transaction, what an invoice must show, when a threshold trips, how a return works) and get an advisor-grade answer with the rule that applied, scoped to your subscribed jurisdictions and saved for later.
• Free public tools. The exposure dashboard, tax-ID validator, filing deadlines lookup, e-invoicing tracker, and filing calendar are free and don't require an account. Quaderno keeps its dataset behind the paywall.
• Draft returns on the authority's form layout. UK VAT100, the OSS return, and the rest arrive as draft PDFs laid out on the actual form structure, each backed by a workings file. With either product, submission is your responsibility; DeterminedAI just leaves much less to do.

3. Comparison table

4. The deciding question: do you need the return prepared inside the product?

Almost everything else flows from this. If your team (or your accountant) is already building your VAT returns and you just need correct calculation at point of sale, Quaderno is the simpler tool. If you want the return workings and a draft return generated inside the same product, DeterminedAI extends further. The other capabilities (country depth, audit trail) follow from the same divide: tools that stop at calculation tend to stop at calculation; tools built around the return give you the workings behind every box.

The crossover usually hits when:

• You're filing in 5+ jurisdictions and building each return by hand costs more than a product that prepares them.
• You've crossed an OSS or country-specific threshold that requires actual registration paperwork (not just calculation).
• You're approaching fundraising and the DD reviewer wants documented return workings, not just calculation reports.
• Your tax authority correspondence is no longer "no news" and you need help working out what each letter requires.

5. Pricing reality

Quaderno pricing

Tiered monthly subscriptions. Quaderno's published tiers as of 2026 are roughly Starter ($49/month for ~250 transactions), Business ($149/month for ~1,000 transactions), and Custom for higher volumes. The all-in cost for a small SaaS doing $500k ARR with 200 monthly transactions is roughly $588/year on Starter. Add accountant fees for the OSS quarterly filing (~$500-1,500 per filing depending on the firm), and the all-in compliance cost lands around $2,500-6,500/year.

DeterminedAI pricing

Headline product is the Compliance subscription, priced per jurisdiction. Starter: $99/jurisdiction/month for 1 to 10 jurisdictions. Growth: $79/jurisdiction/month at 10+ jurisdictions. Enterprise: custom for 50+ jurisdictions, dedicated CSM, SLA. Each subscription bundles the AI tax engine, threshold monitoring, and return workings: every box of the return computed from your transaction uploads, an Excel workings file showing the backing transactions, and a draft return PDF on the authority's form layout, AI-reviewed before you file. Filing stays with you, through your usual channel. EU OSS counts as 1 jurisdiction and covers all 27 EU member states.

For the same $500k-ARR SaaS registered for EU OSS plus UK plus 1 APAC regime, that's 3 jurisdictions on the Compliance subscription: 3 x $99/month = $297/month, or $3,564/year for the tax engine, monitoring, and return workings across all three. Quaderno's calculation-only equivalent at this scale runs roughly $588/year on Starter plus $2,000-$6,000/year in accountant fees for building the OSS quarterly return.

Where the costs land

For pure calculation use cases, Quaderno is cheaper. Once the return itself has to be built, the costs converge, because with Quaderno the workings come from an accountant you bring separately. The decision is rarely about price; it's about whether you want the return prepared inside the product or a thinner tool plus an accountant building it.

6. Use cases

Where Quaderno is the right call

Quaderno suits indie or pre-Series A companies that want the cheapest competent VAT calculation layer, especially when an existing accountant already handles the filings well and a second product would overlap with their work. It also fits footprints that are mostly EU plus a small US sales-tax exposure, where 70+ country depth isn't needed and customer-facing invoice UX matters more than audit-defensible determination logs.

Where DeterminedAI is the right call

DeterminedAI is the better call once you've crossed (or are about to cross) the EU OSS threshold and need the quarterly return worked out box by box, not just calculation, or when you have (or will have) nonresident registrations in APAC, GCC, or LatAm where Quaderno's depth is shallower. The same goes for teams approaching fundraising due diligence who want documented return workings rather than calculation reports, for teams that want one platform from exposure analysis through to a draft return ready to file, with audit-defensible determination at every step, and for anyone who wants to use the free public tools (exposure, validator, deadlines, e-invoicing, calendar) before committing to a paid plan.

7. Migration path

Migration from Quaderno to DeterminedAI is technically straightforward because both products read transactions from Stripe (or your billing platform of record) rather than maintaining a separate transaction store. The handoff:

1. Connect DeterminedAI to your Stripe account. The historical transaction data flows in.
2. Configure your tax registrations in DeterminedAI. The registrations themselves belong to your business, not Quaderno; the registration certificates and OSS scheme number transfer with you.
3. Run one quarter in parallel: keep Quaderno calculating for the live billing flow, run DeterminedAI in shadow mode against the same Stripe data, compare the two on a per-transaction basis.
4. Once parallel running confirms the calculations match, cut over: disable Quaderno's Stripe webhook, enable DeterminedAI's, and prepare the next quarterly return from the workings DeterminedAI generates, then file it through your usual channel.
5. Cancel the Quaderno subscription.

Total migration effort: typically 1-2 weeks elapsed, 4-8 hours of focused work. The longest single step is the parallel-run verification.

8. Frequently asked questions

9. Related reading

• DeterminedAI vs Anrok 2026
• DeterminedAI vs Stripe Tax
• DeterminedAI vs Avalara vs Vertex vs Fonoa
• EU OSS scheme explained
• VAT for Stripe users
• VAT automation software: the 2026 buyer's guide