kalkül alternatives
The 5 best kalkül alternatives in 2026
The short answer: kalkül is a genuinely good free tool — its core features are permanently free. People who look for an alternative usually want one of three things: automation (kalkül has no AI features and reminders are sent manually), design freedom (colors and layout are reserved for paying supporters) or Germany coverage (kalkül states an explicit focus on Austria). For automation, Backbone (formerly Billy; from €19/month incl. VAT) is our pick — it is our own product, and below we are transparent about where it wins and where it does not.
This roundup covers all five serious options — with verified pricing (as of July 2026), honest weaknesses and a clear "best for" per tool.
All alternatives at a glance
| Backbone | ProSaldo.net | FreeFinance | sevDesk | Runple | |
|---|---|---|---|---|---|
| Best for | AI invoicing, dunning with interest, receipts & a ZIP for your accountant (DE/AT) | Bookkeeping with UVA & FinanzOnline, Austria only | Full bookkeeping incl. e-invoicing (ebInterface) | Accounting & e-invoicing in the DACH region, native apps | Trading with inventory; free tier with real dunning |
| Document limit | Monthly allowance per plan; numbers not published yet | Unlimited invoices (all plans) | No invoice limit; OCR via credits (1,000/yr) | Free: 3 invoices/month; paid unlimited | Free: 5/month; Basic: unlimited |
| Price | from €19 / month incl. VAT | from €9 / month (annual) or €10 monthly | invoicing from Plus: €25 / month (12-month term) or €22 (36 months) | from €12.90 / month; free tier: 3 invoices/month | Free (5 invoices/month); Basic €19.90, Standard €29.90 |
| Invoice from AI prompt | Yesassistant Billy, asks before sending | No | No | No | No |
| All features via AI assistant | Yesnearly everything; also from Claude/ChatGPT (MCP) | Nobooking suggestions & OCR only | Noreceipt recognition (OCR) only | Nosuggestions only (receipts, bookings) | NoAI for incoming documents only |
| Professional templates | Partially2 templates (Basic, Minimal), logo + accent color | PartiallyBASIC: fixed layout; designer from PLUS | Partially~43 fonts; free layouts need desktop software | Yes11 layouts, 6 of them Premium | Partiallybranding even on the free plan |
| Live preview | Yesyou write on the page itself | NoPDF preview in a new window | NoPDF preview only in edit mode | – | – |
| Recurring invoices | Yesevery plan | Partiallyfrom PLUS; creates drafts | Partiallya batch you create yourself | Yes | PartiallyStandard (€29.90) and up |
| Automatic email sending | Yesinvoices by email; reminders on schedule from Studio | Noreminders manual per open item | Nobulk dunning — every run started manually | Partiallyseries invoices optionally automatic; dunning manual | Partiallydunning yes (3 stages); series dispatch not documented |
| Bookkeeping | Nono EÜR/VAT filing; export for your tax advisor | Yescash-basis from GO, UVA filing from PLUS | YesUVA & ZM straight to FinanzOnline | Yesin the accounting plan | Yescash-basis free, UVA from Standard |
| E-invoicing | PartiallyZUGFeRD; XRechnung coming soon | PartiallyebInterface to the federal gov., all plans | YesebInterface & XRechnung from Plus | Yeseven in the free tier | Nonot offered |
Competitor pricing and feature claims per the vendors, verified on August 2, 2026, prices net. Backbone details per back-bone.io as of October 9, 2026, prices incl. VAT. Subject to change.
Backbone
Invoices, receipts and dunning with an AI assistantBackbone is the alternative for everyone hitting exactly kalkül’s limits: the AI assistant drafts invoices and quotes from one sentence, sends them after your confirmation, and dunning chases late payers with statutory interest. You also get AI-read receipts, bank statements, time tracking and a ZIP for your accountant, and Austria AND Germany run in the same account.
Full transparency, since Backbone is our product: it is NOT accounting software — cash-basis accounting (E/A-Rechnung), UVA filing and FinanzOnline are absent, as is a BMD export. E-invoicing: ZUGFeRD is live, ebInterface is coming soon. And unlike kalkül, Backbone has no permanently free plan.
Strengths
- Invoices drafted by an AI assistant, sent only after your OK — none of the other tools here can (competitors as of July 2026, per their own sites)
- Dunning with statutory interest and the €40 flat fee where the law allows — own schedule from Studio
- Austria AND Germany in one account (mandatory-detail check under §11 UStG / §14 UStG while you write)
- Clean templates (Basic, Minimal) with logo and accent color, live preview — at no extra cost
- Set up in minutes, cancel monthly; AI-read receipts and a ZIP for your accountant included
Weaknesses
- No bookkeeping: cash-basis accounting, UVA filing and FinanzOnline integration are absent (a UVA template is coming soon), as is a BMD or DATEV export
- E-invoicing only in part: ZUGFeRD is live, ebInterface and XRechnung are coming soon
- No permanent free plan (7-day trial with a card on file, €0 due today)
- Web app rather than a native mobile app; public API coming soon
ProSaldo.net
The Austrian accounting classic (Visma)ProSaldo.net (a Visma product) is the obvious step if you want to grow from kalkül toward bookkeeping: cash-basis accounting from the GO plan, UVA filing straight to FinanzOnline from PLUS — deeply rooted in the Austrian tax system. Invoicing is already in the BASIC plan from €9 net billed annually (€10 monthly).
Do not expect automation, though: reminders are sent manually per open item, the invoice layout on BASIC is fixed and not editable, recurring invoices need PLUS and receipt capture (OCR) needs GO.
Strengths
- Deeply Austrian: cash-basis accounting from GO, UVA straight to FinanzOnline from PLUS
- Invoicing already in the BASIC plan from €9 net (annual billing)
- Established vendor (Visma)
- 30-day trial
Weaknesses
- Reminders only manually per open item
- BASIC layout is fixed and not editable; layout designer only from PLUS
- Recurring invoices only from PLUS, OCR only from GO
- Austria only — Germany is not served
FreeFinance
Austrian cloud accountingFreeFinance is the second big Austrian accounting option: compliant bookkeeping with UVA filing straight to FinanzOnline, plus — as the only tool in this comparison — creation of real e-invoices (ebInterface and XRechnung, from Plus) and around 43 fonts for branding. A 30-day trial is included.
The catch if you come from a free tool: the name misleads. The cheap Business package cannot write invoices — invoicing starts in the Plus package at €25 net per month (€22 on a 36-month term), prepaid; there is no monthly billing. And its dunning is a bulk run you start yourself every time.
Strengths
- Compliant Austrian bookkeeping with UVA straight to FinanzOnline
- Creates e-invoices: ebInterface and XRechnung (from Plus)
- Around 43 fonts for custom branding
- A dedicated German edition exists
- 30-day trial
Weaknesses
- Invoicing only from Plus (€25 or €22 net/month) — the Business package cannot write invoices
- 12- or 36-month terms only, prepaid — not cancellable monthly
- Dunning is a bulk run — you start every run yourself
- Free-form layouts need Jaspersoft Studio on the desktop
sevDesk
The DACH accounting incumbentsevDesk is the best-known name in the DACH region, with a dedicated Austrian offering (sevdesk.at). The "Rechnung" plan starts at €12.90 net (12-month billing), the free tier allows 3 invoices per month — e-invoicing already included. Add native iOS and Android apps and 11 invoice layouts (6 of them Premium).
Its dunning stays manual, though: reminders are sent by hand per invoice, and dunning levels need the accounting plan. And per its own pages, sevDesk’s "AI" means receipt capture plus a support chatbot — not an assistant that creates invoices.
Strengths
- Dedicated Austrian offering (sevdesk.at) plus wide DACH adoption
- E-invoicing even in the free tier (3 invoices/month)
- Native iOS and Android apps
- Full accounting in the bigger plan
Weaknesses
- Reminders manual per invoice; dunning levels need the accounting plan
- Custom layout only as a paid service; colors from a palette only
- AI is limited to receipt capture and a chatbot
Runple
The Austrian business suiteRunple is an Austrian business suite with inventory, warehousing and finance features — and it has the most remarkable free tier in this comparison: 5 invoices per month including genuinely automatic 3-stage dunning, receipt capture and custom branding. On free-tier automatic dunning, Runple beats most tools here — including kalkül, where every reminder is manual work.
In return, Runple is a suite: if you only write invoices, you get trading modules you never open. Recurring invoices need the Standard plan (€29.90), Runple creates no e-invoices, and Germany is not served (Austria focus, no DATEV).
Strengths
- Free tier: 5 invoices/month with automatic 3-stage dunning
- Receipt capture and custom branding even on the free tier
- Full inventory management for trading businesses
- Austrian vendor
Weaknesses
- Recurring invoices only from Standard (€29.90)
- No e-invoicing
- Suite breadth is dead weight for pure service businesses
- No Germany (Austria focus, no DATEV)
How we evaluated
All pricing and feature claims come from the vendors’ own pricing and help pages, last verified on 31 July 2026 (Backbone details: as of 9 October 2026) — including the inconvenient details like tier gating and dunning limitations. Where a vendor does not document something (such as the price of kalkül’s supporter subscription), we do not claim it. Backbone is our own product: we rank it #1 for the use case it is built for, and we state its weaknesses as plainly as everyone else’s.
Do not choose Backbone if …
Backbone is ranked first on this page, and this page belongs to Backbone (formerly Billy). So that you can weigh that: here are the cases where another tool is the better choice.
- You already invoice public-sector clients (XRechnung)Backbone produces ZUGFeRD e-invoices, but XRechnung (and Austria’s ebInterface) is only coming soon. sevDesk, easybill and FastBill ship XRechnung in their cheapest tier, and in Austria FreeFinance creates ebInterface and XRechnung. If you must bill public-sector clients today, choose one of those.
- You want to do your bookkeeping inside the toolBackbone collects receipts, matches them to payments and takes bank statements, but deliberately does no bookkeeping: no EÜR, no P&L, no VAT return via ELSTER or FinanzOnline. Your tax advisor does the books from the export. If you want everything from one tool, take sevDesk, Lexware Office, or FreeFinance in Austria.
- Your tax advisor insists on a DATEV or BMD exportBackbone has none. It delivers a named ZIP of receipts, sent invoices, bank statements and a CSV report — or a free bookkeeper login. Any accountant can open that, but it is not a DATEV interface. If your accountant insists on one, that rules Backbone out — sevDesk and Lexware Office are built for it.
- You want a native mobile appBackbone is a web app: it runs in your phone’s browser and you can upload receipt photos with it — but there is no native app in the store (a Mac app for the timer is coming soon). sevDesk, Lexware Office, FreshBooks, Wave, Zoho and Square all ship one.
- You never want to payBackbone has no free plan: after a 7-day trial (card on file at Stripe, €0.00 due today) it costs from €19 a month incl. VAT. easybill (50 documents a month) and sevDesk (3 invoices a month) have permanently free tiers, and in the US so do Wave and Zoho Invoice.
- Your business is based in the USBackbone is built for Germany and Austria. It invoices in English and in USD, GBP or CHF too — for a German or Austrian business billing clients abroad. It does not handle US sales tax. For a US-based business, QuickBooks, FreshBooks, Wave, Zoho Invoice or Square are the better-fitting tools.