The Calculator Blog
Learn to master your finances, optimize your home and boost your professional career with our expert guides.
Latest
Health · 8 min read
Weight, calories, hydration and heart rate: reading your health numbers
What BMI does and does not measure, how many calories you need a day, how much water you really need, and how to use heart rate training zones.
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Expert guide
Finance
The mortgage from start to finish: payment, interest and early repayment
How your mortgage payment is calculated, why almost all of it is interest at the start, and how much you really save by repaying early.
1 Jun · 6 min read
Finance
APR, nominal rate and how to compare loans without getting it wrong
The difference between the nominal rate and the APR, which costs each one includes, and how to compare two loan offers that look alike but are not.
2 Jun · 7 min read
Finance
Compound interest and percentages: the maths of saving
5 min read
Finance
Rent or Buy a Home in Spain? The Definitive Guide
5 min read
Finance
Your payslip explained: from gross to net and the tax withheld
6 min read
Finance
VAT Rates in Spain: Standard, Reduced and Super-Reduced
4 min read
Home
The two fixed costs that weigh most at home: your car and your electricity
6 min read
Work
End of contract: final settlement, unemployment benefit and the deadlines
12 min read
Work
Self-Employed Contribution 2026: Income Brackets and What's New
5 min read
Work
Retirement Pension in Spain: How It Works and How Much You Will Receive
5 min read
Work
Mandatory Working Time Recording in Spain: What It Is and How to Comply
4 min read
Education
Everyday maths: proportions, units and weighted averages
11 min read
Education
Kinematics with real examples: uniform and accelerated motion
4 min read
Education
How the Spanish DNI letter is calculated (and why it exists)
3 min read