Calculators for invoices and quick maths
Five calculators for sums that come up often and are easy to get wrong. The VAT and IRPF ones are built for invoicing as a freelancer in Spain: start from the net amount or from what you want to be paid, pick the VAT rate (21, 10 or 4%) and the withholding (15, 7 or 19%), and get the full breakdown with cent rounding that matches the invoice.
The other three work for anyone. The percentage calculator finds X% of a number, what share one amount is of another and how much a price went up or down. The rule of three shows the formula with your values so you can see where the answer comes from. And the business days calculator counts working days between two dates with Spain’s national holidays for any year, Good Friday included, so you can estimate a deadline without counting on your fingers.
All 5 tools
- Spanish VAT calculatorAdd Spanish VAT to a net amount or take it out of a total, at 21, 10 or 4% or any rate you need. Cent rounding that always adds up.
- Spanish IRPF withholding calculatorWork out a Spanish freelance invoice with VAT and IRPF withholding (15, 7 or 19%) from the base or from what you want to be paid, fully broken down.
- Percentage calculatorWork out X% of a number, what percentage one amount is of another and the percentage change between two values, with discounts and markups.
- Rule of three calculatorSolve direct and inverse rules of three: if A goes with B, what goes with C. Shows the formula with your values so you can see where the result comes from.
- Business days calculatorCount calendar days, weekdays and business days between two dates, with Spain’s national holidays worked out for any year, Good Friday included.