Title: KleinBooks – German Invoicing & Buchhaltung Author: opskleinbooks Published: September 30, 2026 Last modified: September 30, 2026 --- Search plugins ![](https://ps.w.org/kleinbooks/assets/banner-772x250.png?rev=3720787) ![](https://ps.w.org/kleinbooks/assets/icon-256x256.png?rev=3721226) # KleinBooks – German Invoicing & Buchhaltung By [opskleinbooks](https://profiles.wordpress.org/opskleinbooks/) [Download](https://downloads.wordpress.org/plugin/kleinbooks.1.9.14.zip) * [Details](https://pirate.wordpress.org/plugins/kleinbooks/#description) * [Reviews](https://pirate.wordpress.org/plugins/kleinbooks/#reviews) * [Installation](https://pirate.wordpress.org/plugins/kleinbooks/#installation) * [Development](https://pirate.wordpress.org/plugins/kleinbooks/#developers) [Support](https://wordpress.org/support/plugin/kleinbooks/) ## Description **Heute Kleinunternehmer, morgen mit Umsatzsteuer — KleinBooks wächst mit.** KleinBooks brings the German business workflow — **Angebot Rechnung** (quote invoice)— directly into your own WordPress admin. No second tool, no monthly SaaS subscription. Start as a Kleinunternehmer (§19 UStG); when your business passes the €25,000 limit, switch to Regelbesteuerung (standard VAT) with one confirmed click and keep working in the same tool. #### Free * Write quotes (Angebote) and convert them to an invoice in one click * Invoices with the German mandatory fields (§14 UStG) and sequential numbers * Clean PDF invoices & quotes, sent by email * Clients, and expenses with categories, recurring costs and receipt upload * Dashboard and a Taxes overview: revenue, expenses, profit and an estimated tax reserve * §19 thresholds (€25,000 previous year / €100,000 current year) with a warning before you reach them * **Kleinunternehmer Regelbesteuerung switch** — 19 % / 7 % VAT, net / VAT / gross on invoices and quotes, USt-IdNr, input VAT (Vorsteuer) on expenses and a VAT- owed (USt-Zahllast) overview. Invoices you already issued keep their tax treatment. #### Pro KleinBooks Pro (€59 / year plus VAT, 14-day free trial without credit card) is a separate paid version for when you need to be audit-ready: * **GoBD lock** — sent invoices can no longer be changed; corrections go through a proper Stornorechnung (own number) and an optional correction invoice * **DATEV export** (EXTF, SKR03/SKR04) for your tax advisor * **USt-Voranmeldung** — your quarterly or monthly VAT return figures (Ist or Soll taxation) with PDF * **ZUGFeRD / Factur-X e-invoices** — for VAT-registered businesses (issuing becomes mandatory from 2027/2028); Kleinunternehmer are exempt from issuing e-invoices * **AfA / Abschreibung** — depreciation of assets The free version is an invoicing tool: sent invoices stay editable. GoBD lock with Storno is part of KleinBooks Pro. #### Source code The admin app is built with React (@wordpress/scripts). The full unminified source for the compiled bundle in `assets/`, together with build instructions, is included in the plugin’s `src/` directory. ## Screenshots [⌊Dashboard: revenue, open invoices, expenses and your Kleinunternehmer limit at a glance.⌉⌊Dashboard: revenue, open invoices, expenses and your Kleinunternehmer limit at a glance.⌉[ Dashboard: revenue, open invoices, expenses and your Kleinunternehmer limit at a glance. [⌊Invoices with automatic sequential numbers, status, due date and payment tracking.⌉⌊ Invoices with automatic sequential numbers, status, due date and payment tracking .⌉[ Invoices with automatic sequential numbers, status, due date and payment tracking. [⌊Clean invoice PDF with the §19 UStG notice, ready to send by email.⌉⌊Clean invoice PDF with the §19 UStG notice, ready to send by email.⌉[ Clean invoice PDF with the §19 UStG notice, ready to send by email. [⌊Quotes (Angebote) that turn into an invoice in one click.⌉⌊Quotes (Angebote) that turn into an invoice in one click.⌉[ Quotes (Angebote) that turn into an invoice in one click. [⌊Expenses by category, including recurring subscriptions.⌉⌊Expenses by category, including recurring subscriptions.⌉[ Expenses by category, including recurring subscriptions. [⌊Taxes: profit, tax reserve estimate and the §19 UStG thresholds.⌉⌊Taxes: profit, tax reserve estimate and the §19 UStG thresholds.⌉[ Taxes: profit, tax reserve estimate and the §19 UStG thresholds. [⌊Settings: switch between Kleinunternehmer (§19) and Regelbesteuerung (VAT) with one confirmed click.⌉⌊Settings: switch between Kleinunternehmer (§19) and Regelbesteuerung( VAT) with one confirmed click.⌉[ Settings: switch between Kleinunternehmer (§19) and Regelbesteuerung (VAT) with one confirmed click. ## Installation 1. Install KleinBooks from the WordPress plugin directory, or upload it to `/wp-content/ plugins/kleinbooks`. 2. Activate the plugin through the **Plugins** screen in WordPress. 3. Open **KleinBooks** in the admin menu and create your first invoice. ## FAQ ### Is KleinBooks free? Yes. Quotes, invoices, expenses and the §19 Regelbesteuerung switch are free and fully functional. GoBD lock with Storno, DATEV export, USt-Voranmeldung, e-invoicing and AfA are part of KleinBooks Pro. ### I’m over the €25,000 Kleinunternehmer limit — does KleinBooks still work for me? Yes. In Settings, switch the tax regime from Kleinunternehmer (§19) to Regelbesteuerung. New invoices and quotes then show net, VAT (19 % or 7 %) and gross amounts and your USt-IdNr; invoices you already issued keep their §19 treatment. KleinBooks never switches automatically — it warns you as you approach the limits, and you decide when to switch (ideally together with your tax advisor). ### Does the free version make me GoBD-compliant? No. The free version is an invoicing tool — sent invoices stay editable. The GoBD lock with Storno, DATEV export and e-invoicing are part of KleinBooks Pro. ### Do I need an external service or account? No. KleinBooks runs entirely inside your own WordPress install. Your invoicing data stays on your own site. ### Can I write quotes (Angebote)? Yes, in the free version. Write an Angebot, send it as a PDF by email, and when the client accepts, convert it into a draft invoice in one click — the invoice stays editable so you can make any last changes before sending. The quote and the invoice stay cross-linked so you always see where each one came from. ## Reviews There are no reviews for this plugin. ## Contributors & Developers “KleinBooks – German Invoicing & Buchhaltung” is open source software. The following people have contributed to this plugin. Contributors * [ opskleinbooks ](https://profiles.wordpress.org/opskleinbooks/) * [ Freemius ](https://profiles.wordpress.org/freemius/) [Translate “KleinBooks – German Invoicing & Buchhaltung” into your language.](https://translate.wordpress.org/projects/wp-plugins/kleinbooks) ### Interested in development? [Browse the code](https://plugins.trac.wordpress.org/browser/kleinbooks/), check out the [SVN repository](https://plugins.svn.wordpress.org/kleinbooks/), or subscribe to the [development log](https://plugins.trac.wordpress.org/log/kleinbooks/) by [RSS](https://plugins.trac.wordpress.org/log/kleinbooks/?limit=100&mode=stop_on_copy&format=rss). ## Changelog #### 1.9.14 * Contains all 1.9.13 changes (1.9.13 was only released as KleinBooks Pro). * Privacy: invoice PDFs are no longer stored as public files; they are only shown to logged-in users. Receipt files get unguessable names. * Fixed: an invoice number is never reused, even after deleting an issued invoice. * New invoices get a due date from your payment terms; invoices without one no longer show as overdue. #### 1.9.13 * Privacy: invoice PDFs are no longer stored as public files; they are only shown to logged-in users. Receipt files get unguessable names. * Fixed: an invoice number is never reused, even after deleting an issued invoice. * New invoices get a due date from your payment terms; invoices without one no longer show as overdue. * The estimated tax reserve no longer goes below zero. #### 1.9.12 * Fixed: adding a second client failed with “Failed to save client” on new installs. * Clients page shows errors in the app instead of browser popups. * PDF invoices and quotes now show quantity × unit price on every line (§14 UStG), German dates, and the address in standard German order. * Converting a quote into an invoice uses the normal invoice number format (e.g. RE-2026-002). * Amounts with cents always show two decimals (149,50 €). * New plugin icon. #### 1.9.11 * Fixed: activating KleinBooks Pro while the free version is active no longer fails— the free version is switched off automatically. * Fixed: a cancelled invoice’s Stornorechnung appears in the list right away; empty due dates no longer show “Invalid Date”. * Dashboard: the Kleinunternehmer budget now uses paid revenue against the €25,000 limit, the same figures as the Taxes page. * Settings shows the real invoice number format (e.g. RE-2026-001). #### 1.9.10 * An invoice now counts as issued as soon as it leaves Draft — by email, “Issue Invoice” or setting it to Paid — and its issue date is recorded in every case. * Settings: corrected the Kleinunternehmer note to the current limits (€25,000 previous year / €100,000 current year, since 2025). * Plugin description and Help page now mention the Regelbesteuerung (VAT) switch and the USt-Voranmeldung in Pro. * Upgrade cards show the actual Pro price (€59 / year plus VAT) and link to the 14-day free trial. * The KleinBooks icon now shows on the opt-in and pricing screens. #### 1.9.9 * Translations now come from translate.wordpress.org; bundled language files removed. * This plugin no longer contains any code for KleinBooks Pro features. Pro (GoBD lock + Storno, DATEV export, AfA, ZUGFeRD) is a separate download. * The shipped React source in src/ now exactly matches the compiled bundle in assets/. #### 1.9.8 * Updated bundled library sabberworm/php-css-parser to 9.4.0 (used by dompdf for CSS/SVG parsing) and its dependency thecodingmachine/safe to 3.4.0. * Minimum PHP raised to 8.1, required by the updated libraries. #### 1.9.7 * All CSS/JS now loads through the WordPress enqueue API (app page + admin pages; new assets/admin.css). * React app source now included in the plugin (src/ with build instructions). * Library updates: dompdf 3.1.5 (PDF rendering verified identical), Freemius SDK 2.13.4, security patches for bundled fpdi/symfony components. * Translations load on init (WP 6.7+ i18n timing). * Fixed a corrupted CSS color value on the Email Log page. #### 1.9.6 * Header fix: distinct Plugin URI / Author URI (WordPress.org requires them to differ; removed the redundant Author URI). No functional change. #### 1.9.5 * Final WordPress.org Plugin Check pass (0 errors on the generated free build) — resolved a last static-analysis flag on a prepared query. No functional change. #### 1.9.4 * Invoice and offer numbers are now year-based (e.g. RE-2026-009 / ANG-2026-009) so they stay unique across years, as §14 UStG requires. Existing numbers are unchanged; new default prefix is RE-. * Internal WordPress.org compliance hardening. #### 1.9.3 * Hardening & WordPress.org compliance: fonts bundled locally (no external requests— GDPR-friendly), uploads handled through WordPress core (wp_handle_upload), complete output escaping, and internal code cleanup. Passes the official Plugin Check with no errors. No feature changes. #### 1.9.1 * Freemium launch. Free core: German invoicing (§14 UStG), PDF & email, client management, expenses, dashboard. * **New: Angebote (quotes/offers)** — write quotes, send them as PDF, and convert an accepted quote into a draft invoice in one click, with a bidirectional link between the two. * Quote numbering with a configurable prefix and validity period (Gültigkeit), quote status tracking (sent / accepted / declined / expired / converted). * Invoice & quote emails are now in German. * KleinBooks Pro adds ZUGFeRD / Factur-X e-invoicing, DATEV export (EXTF, SKR03/ SKR04), GoBD lock + Storno (cancellation), and AfA / Abschreibung. ## Meta * Version **1.9.14** * Last updated **5 hours ago** * Active installations **Fewer than 10** * WordPress version ** 6.0 or higher ** * Tested up to **7.1.2** * PHP version ** 8.1 or higher ** * Language * [English (US)](https://wordpress.org/plugins/kleinbooks/) * Tags * [buchhaltung](https://pirate.wordpress.org/plugins/tags/buchhaltung/)[invoice](https://pirate.wordpress.org/plugins/tags/invoice/) [Rechnung](https://pirate.wordpress.org/plugins/tags/rechnung/) * [Advanced View](https://pirate.wordpress.org/plugins/kleinbooks/advanced/) ## Ratings No reviews have been submitted yet. [Your review](https://wordpress.org/support/plugin/kleinbooks/reviews/#new-post) [See all reviews](https://wordpress.org/support/plugin/kleinbooks/reviews/) ## Contributors * [ opskleinbooks ](https://profiles.wordpress.org/opskleinbooks/) * [ Freemius ](https://profiles.wordpress.org/freemius/) ## Support Got something to say? Need help? [View support forum](https://wordpress.org/support/plugin/kleinbooks/)