Free calculators for freelancers
Kuenta, free calculators and invoices for freelancers
Kuenta is my portal of free tools for freelancers, SMEs, and individuals in Spain: VAT, personal income tax, freelancer's fee, and forms 303 and 130 calculators, net salary, severance pay, and unemployment calculators, mortgage and hourly rate calculators, a NIF, NIE, and CIF verifier, and generators for invoices, quotes, delivery notes, and receipts in PDF.
Everything works in the browser, without registration and with the 2026 regulations. It's the first phase of a larger project: an account to save calculations and an ERP with VeriFactu invoicing, which already has a waiting list.
- 15 free tools, each with its own page
- 0 registrations: everything is calculated in the browser
- 4 PDF documents: invoice, quote, delivery note, and receipt
- Sector Online tools for freelancers and SMEs
- Public Freelancers, SMEs, and individuals in Spain
- Project Proprietary product by Adrián Alcalá
- Technology Custom development, without a content manager
What the Kuenta portal includes
- One page per tool: With its own address, like /tools/vat-calculator/, to appear on Google for each search.
- Calculation in the browser: Figures do not leave the user's device: no waiting or registrations.
- Invoices and quotes in PDF: No watermark; sender's data is saved only in the browser.
- Linked guides: 15 guides on the blog, each with its tool, for those who want to understand the calculation.
- Roadmap in sight: What's there, what's coming, and the ERP waiting list, explained on the website.
- Light and fast: Own HTML, CSS, and JavaScript, without external dependencies, so it opens instantly.
The design
Electric blue on white, a night blue for the text and a green for the results: a clear tool, understood at first glance.
- #2F6BFF blue
- #1D4ED8 deep blue
- #0F1729 night blue
- #EAF1FF light blue
- #12A150 green
Typography: Inter across the entire website
Custom web development from Dénia
Not everything has to be on WordPress. From Dénia, I do custom developments when the project requires it —tools, calculators, web applications— and websites with a manager when it's convenient for you to manage them. I explain the difference to you in web design or web development.
The website inside
This is how kuenta.es is today. Above, the homepage from beginning to end; below, three of its 15 tools working with the example they load with a click.
The kuenta.es homepage as it is today, from top to bottom: the presentation, the most searched tools and three calculators in action.
Create invoice: On the left, the sender's data, the client's data and the concepts are filled in; on the right, the invoice is seen as it will come out, with VAT and IRPF withholding already calculated. It is downloaded in PDF without registration or watermarks. Open the invoice creator
Model 303 simulator: The quarterly VAT declaration: sales at 21, 10 and 4 %, input VAT and what remains to be compensated are entered, and instantly it shows if the quarter is to be paid or compensated. Next to it, the formula explained and tips so that the 303 doesn't catch you off guard. Open the 303 simulator
Net salary calculator: From annual gross to net of each payment, in 12 or 14 payments and according to dependents, with the IRPF tax brackets and 2026 contributions. Next to it, what each discount comes from and the IRPF tax bracket table. Open the salary calculator
The starting point
Tax calculators are among the most repeated searches, and almost all websites that offer them take time to load, ask for registration, or fill the screen with ads before the result. The opportunity was to make them fast and frictionless.
The solution
A portal with fifteen tools —VAT, personal income tax, net salary, freelancer's fee, severance pay, mortgage, unemployment, forms 303 and 130, hourly rate, NIF/NIE/CIF verifier— and generators for invoices, quotes, delivery notes, and receipts. Everything is calculated in the browser itself, without registration.
How it was done
- We discarded the content manager: for this, it's too heavy and slows down loading.
- Custom development, with each tool on its own page.
- Calculations happen in the user's browser: no waiting or data leaving the device.
- A clean URL per tool, which is what allows each search to be positioned.
- Support blog, and installable as a mobile application.
How it turned out
Each calculator competes for its search with its own page that opens instantly and gives the result without asking for anything in return.
Project type: Tools portal · custom development
Technology: Own development in HTML, CSS, and JavaScript, without a content manager · installable as an application
Web: kuenta.es
