🇪🇸 Español 🇬🇧 English

Exam Probability Calculator

Calculate your chances of getting a topic you know

Enter data to calculate

Enter data to calculate

How is exam topic probability calculated?

With this exam topic probability calculator, you'll know in seconds how likely you are to get a topic you already know. It's fast, simple, and extremely useful to get a clear idea of how prepared you are and what your chances are. Just indicate how many topics your specialty has, how many you've prepared, and how many are drawn in the ball lottery.

How does the calculator work?

The tool is very simple: you enter how many topics your exam has, how many you've studied, and how many balls are drawn. In seconds you get the real probability that at least one of your prepared topics will be drawn and a simulation of the topic draw that could happen on exam day. Ideal for exams like Teaching, Administrative, or Justice positions.

Mathematical formula used

P = 1 - (C(T-E, B) / C(T, B))

Beneficios

  • Uses hypergeometric distribution, an exact mathematical model for draws without replacement
  • Doesn't predict the future, but gives you the most accurate estimate possible of your real chances
  • 100% free and no registration required. You can use it as many times as you want with different combinations
  • Works for any type of teaching exam (Primary, Secondary, Vocational...), Administration, Justice, Healthcare, etc.
  • Includes draw simulations to visualize possible exam day scenarios

Frequently Asked Questions

How exactly does the topic probability calculator work?
The tool is very simple: you enter how many topics your exam has, how many you've studied, and how many balls are drawn. In seconds you get the real probability that at least one of your prepared topics will be drawn and a simulation of the topic draw that could happen on exam day. Ideal for exams like Teaching, Administrative, or Justice positions.
How reliable is the probability calculation?
Our exam probability calculator uses the hypergeometric distribution formula, an exact mathematical model that applies to draws without replacement (like drawn balls). It doesn't predict the future, but it gives you the most accurate estimate possible of your real chances.
Do I need to register or pay to use the calculator?
No, this tool is 100% free and requires no registration. It's designed to help you prepare for your exam with objective data and without complications. You can use it as many times as you want, with different combinations of topics and balls.
Does this calculator work for any type of exam?
Yes, you can use it for teaching exams (Primary, Secondary, Vocational...), General Administration, Justice, Healthcare, etc. It works for any selective process where there's a random topic draw, as long as you know the total topics and the number of balls drawn.
Why is the topic probability in exams so high?
The probability can seem high when you prepare a significant portion of the syllabus. For example, if you study half the topics and 2 balls are drawn, you have around 75% probability. However, this doesn't guarantee success, as you also need to master those topics well and present them correctly on exam day.
How many topics should I prepare to have good chances?
It depends on the number of balls drawn. As a general rule, preparing at least 2/3 of the syllabus gives you probabilities above 85-90% with 2 balls drawn. You can use this calculator to try different scenarios and decide how many topics you need to study based on your target probability.