How to Calculate Your IQ

How to Calculate Your IQ – A Complete Guide

📊 What IQ Really Is – And Why You Can’t “Just Count” It

IQ (Intelligence Quotient) is not simply the number of questions you get right on a test. It’s a standardized score that shows how your cognitive abilities compare to those of other people in your age group. In most modern IQ scales:

• The average IQ is set at 100.

• The standard deviation (SD) is usually 15.

This means IQ is always relative to a norm group. Without knowing those norms (average and SD), you can’t calculate IQ precisely — and that’s why “counting” IQ without context is meaningless.

🧮 The Real Formula: IQ = 100 + z × 15

Here’s how IQ is calculated step by step:

1. ✅ You take an IQ test and get a raw score — for example, 32 correct answers.

2. 📊 The test creators provide normative data — e.g., the average score for your age group is 25, with a standard deviation of 5.

3. 📈 Calculate the z-score (how many SDs above or below average you are):

   z=your raw score−average raw scoreSDz = \frac{\text{your raw score} – \text{average raw score}}{\text{SD}}z=SDyour raw score−average raw score​

4. 🔢 Convert the z-score into the IQ scale:

   IQ=100+z×15IQ = 100 + z \times 15IQ=100+z×15

💡 Result: IQ is not the raw number of correct answers — it’s how far above or below average you are compared to others.

📘 Example: Real IQ Calculation

• Your raw score: 32

• Average for your age: 25

• SD: 5

Step 1 – Calculate z-score:

z=(32−25)/5=1.4z = (32 – 25) / 5 = 1.4z=(32−25)/5=1.4

Step 2 – Convert to IQ:

IQ=100+1.4×15=121IQ = 100 + 1.4 × 15 = 121IQ=100+1.4×15=121

✅ Your IQ is approximately 121, which is higher than about 92% of people in your age group.

🧠 Official Tests That Accurately Measure IQ

If you want a reliable, scientifically valid IQ result, only standardized and normed tests can give it:

• WAIS – Wechsler Adult Intelligence Scale

• WISC – Wechsler Intelligence Scale for Children

• Stanford–Binet

• Raven’s Progressive Matrices

These tests are administered by licensed professionals and have updated norms based on large, diverse populations.

💻 Can You Calculate IQ from an Online Test?

Short answer: Only approximately.

Most free online IQ quizzes are not standardized — they don’t use scientific norms. If they provide your raw score and publish the average and SD for your age group, you can use the formula above. But without those numbers, any result they give is just a rough estimate.

👉 Tip: Look for online tests that clearly explain how they normalize results, how large their sample is, and when norms were last updated (because of the Flynn effect — IQ scores tend to rise over decades).

📚 How to Prepare for an IQ Test

IQ tests measure fundamental cognitive abilities — not memorized knowledge. But your score can vary depending on conditions. Here’s how to prepare:

• 😴 Sleep 7–9 hours before testing.

• 🥗 Eat a light meal about an hour beforehand.

• 📵 Choose a quiet environment.

• 📘 Familiarize yourself with question types (patterns, analogies, sequences).

• ⏱️ Practice time management — don’t waste too much time on one question.

• 🕐 Take the test at your mental “peak time” (morning for some, afternoon for others).

⚠️ Common Mistakes When Calculating IQ

1. ❌ Comparing raw scores from different tests — they’re not equivalent.

2. ❌ Ignoring age norms — IQ is always age-relative.

3. ❌ Drawing conclusions from a single, short test.

4. ❌ Treating online results as official.

5. ❌ Overemphasizing the number — IQ is just one measure of intelligence.

📈 Understanding IQ Levels

IQ ScoreCategoryDescription< 70Significantly below averagePossible cognitive difficulties85–115Average~68% of population115–130Above averageStrong cognitive abilities130+Very high~2% of population

Remember: IQ does not measure creativity, emotional intelligence, motivation, or perseverance — all of which are crucial to success.

🧠 Converting Percentages to IQ (If You Only Know % Correct)

Some online tests give only a percentage of correct answers. Here’s what you can do:

1. Find out the average percentage for your age group and the standard deviation.

2. Convert your score to a z-score using the same formula.

3. Then calculate IQ: IQ=100+z×15IQ = 100 + z × 15IQ=100+z×15.

If no norms are available, the result is not a real IQ — just a raw performance score.

✅ Checklist: Correct Steps to Calculate IQ

• Take a validated test.

• Obtain your raw score and age-specific norms.

• Calculate your z-score.

• Convert z-score to IQ.

• Compare your result to the percentile and interpret it in context.

❓ FAQ

Q: Can I improve my IQ? A: You can improve your test performance — by sleeping well, reducing stress, practicing logic puzzles, and understanding test formats. Long-term cognitive growth is possible through learning, mental challenges, and healthy lifestyle choices.

Q: Why do I get different IQ scores on different tests? A: Norms, question types, time limits, and testing conditions differ. Use only standardized tests for reliable results.

Q: Is there a way to calculate IQ at home? A: Not precisely. Without official norms and testing conditions, any calculation will be approximate.

🧭 Final Thoughts

To calculate your IQ, you must:

1. Take a standardized, normed test.

2. Get your raw score and norm data.

3. Use the formula:

   IQ=100+(your score−average)SD×15IQ = 100 + \frac{(\text{your score} – \text{average})}{\text{SD}} × 15IQ=100+SD(your score−average)​×15

4. Interpret the result based on percentiles and subtest profiles — not just the single number.

👉 IQ is a helpful indicator, but it’s only one part of the bigger picture. Your potential is far more than a number — it includes creativity, motivation, social skills, and emotional intelligence. Use IQ as a tool for growth, not as a label.