Free calculators, no sign-up
Each calculator runs in your browser, keeps the numbers in the URL so you can share it, and explains the maths behind it. None of them asks you to create an account.
- Free
Net worth
Add up what you own, subtract what you owe and get your net worth. Free, no sign-up, with a link that keeps your numbers.
- Free
Compound interest
See how your savings grow with monthly deposits and an annual rate. Split what you put in from what the interest earned.
- Free
Emergency fund
Work out how big your emergency fund should be from your expenses, how much is missing and how many months it takes to complete.
- Free
Savings goal
Set a target, what you already have and the months left. The calculator tells you how much to set aside each month, with and without interest.
- Free
Financial independence (FIRE)
Calculate the capital you need to live off your investments with the 4% rule and how many years it takes at your savings rate.
- Free
50/30/20 rule
Split your net monthly income into needs, wants and savings with the 50/30/20 rule, or with the percentages you choose.
- Free
Autónomo quota 2026
Find your net income band and the minimum self-employed (RETA) quota for 2026, using the current table (Orden PJC/297/2026) and the 0.9% MEI.
- Free
Quarterly VAT (modelo 303)
Estimate your modelo 303 result: output VAT by rate, deductible input VAT and the amount to pay or carry forward.
- Free
IRPF instalment (modelo 130)
Estimate the quarterly IRPF instalment with modelo 130's cumulative logic: 20% of the year's profit minus what you already paid and the withholdings.
- Free
How much to set aside for tax
Work out how much of each invoice is yours and how much to set aside for VAT and IRPF, based on the VAT rate and the withholding you apply.
- Free
Invoice net amount
Calculate the total of a Spanish invoice with VAT and IRPF withholding: what you collect, how much is VAT and how much the client withholds.
- Free
Mortgage
Work out the monthly instalment of a Spanish mortgage, the interest you will pay over its whole life and the share of the price you are financing.
- Free
Personal loan
Work out the instalment of a personal loan, the real APR once the arrangement fee is counted, and what you end up paying in total.
- Free
Refinance the mortgage
Compare your current mortgage with a new one and work out the net saving, the drop in instalment and how many months it takes to earn the fees back.
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