What an IXL SmartScore actually means
By Jasa Todorovich. Last updated Sep 27, 2026
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The short answer
A SmartScore is IXL's 0-100 measure of how well a student understands one skill. It is not the percentage of questions they answered correctly. IXL's own thresholds are:
| SmartScore | What IXL calls it |
|---|---|
| 100 | Mastery |
| 90 | Excellence, the entry point to IXL's Challenge Zone |
| 80 | Proficiency |
So a student sitting at 80 has met IXL's bar for proficiency on that skill, and a student at 100 has mastered it. Everything below 80 is work in progress, not a failing grade.
Why it is not a percentage
In a percentage grade, a missed question is a permanent deduction. IXL describes the SmartScore as "completely different": a student who starts badly and then answers well can still reach 100 in the same session.
The score also drives the questions. IXL states that when a student answers correctly and the SmartScore rises, the following questions get harder; when they answer incorrectly the score falls and the following questions get easier. That is why two students with the same SmartScore have usually seen different questions, and why the score is a reading of current understanding rather than a record of the session.
How the SmartScore moves, question by question
Every student starts a skill at 0. IXL says the score rises with correct answers and falls with incorrect ones, and that it is calculated from several factors, including the number of questions completed, question difficulty and consistency. IXL does not publish the formula.
What IXL does publish is how the size of each step changes as the score climbs. Its SmartScore guide for teachers and parents describes three stages:
| SmartScore | What IXL says happens |
|---|---|
| 0 to 70 | Learning and practicing. Large increases for correct answers and low penalties for incorrect answers. |
| 71 to 90 | Building determination. Mid-level to high-level rigor questions. 80 is proficiency. |
| 90 to 100 | The Challenge Zone. Increases of 1 or 2 points for a correct answer, penalties of 3 to 8 points for an incorrect one. |
So the score rises quickly early on and slowly near the top, and a missed question in the Challenge Zone costs more than one in the early stage.
What the Challenge Zone is
The Challenge Zone is the stretch from 90 to 100 in math and language arts skills. IXL says students enter it when they reach a SmartScore of 90 and collect their third ribbon, and that it holds the most difficult questions in the skill. Students must answer those questions correctly and consistently to reach 100.
IXL explains the smaller gains and larger drops inside the zone as giving students more time to explore the topic before they reach mastery. Progress is saved, so a signed-in student can stop and come back to the same place.
How many questions it takes to reach 80, 90 or 100
IXL does not publish a fixed number. It says the number of questions it takes to master a skill varies with every student, and that the score is calculated from many factors rather than from the percentage of questions correct.
The one figure IXL gives is for the end: in the Challenge Zone, students will need to answer as many as 10 questions correctly in a row to reach 100. IXL gives no count for reaching 80 or 90.
What happens at 100, and after it
A student who reaches 100 has mastered the skill in IXL's terms, and IXL describes it as earning a gold medal.
IXL's reports keep that mastery visible. The Skill Score Chart shows each student's SmartScore as "current score or prior mastery" by default, which IXL says means a student who restarted a skill after mastering it still appears as 100. The only case where the two differ, IXL notes, is when the student's SmartScore has been reset. A teacher can switch the report to the current school year only.
What a score of 70 means
IXL places 0 to 70 in its learning and practicing stage, where a student is still building confidence in the skill, with large gains for correct answers and low penalties for mistakes. In the Skill Score Chart, a student who has answered at least one question and scores below 80 is grouped as Practiced, one step below Proficiency.
Setting a SmartScore goal
Teachers can set a SmartScore goal for the skills they suggest in math, language arts and Spanish, choosing Proficiency (80), Excellence (90) or Mastery (100). IXL describes 80 as a strong understanding of the concept and 90 as consistently capable of answering high-rigor questions. The student sees a checkmark when the goal is met, and if the score later drops below the goal, the checkmark is replaced by the goal again.
What a SmartScore does not tell you
It does not place a student against their grade level. A SmartScore measures one skill and moves within a single practice session. IXL's LevelUp Diagnostic is the product that places a student above, on, below or far below grade level, and it reports on a different scale entirely, where a level such as 450 reads as a grade. Averaging or trending the two together compares two different measurements.
It does not carry over between skills. Each IXL skill has its own SmartScore. A student with 100 on "Add fractions with like denominators" has said nothing yet about unlike denominators.
A score can be stale. IXL recalculates a skill's SmartScore as a student returns to it, so a number from three months ago describes three months ago.
How to read a SmartScore as a teacher
- 100 is the only number that means mastery. Treat 80-99 as real progress that is not finished.
- A drop between two sessions on the same skill is worth more attention than a low first score. The first score is a starting point; a fall is a change.
- Time matters as much as the number. A 70 reached in six minutes and a 70 reached in forty minutes are different situations for the same child.
- A benchmark session is not practice. If your school runs the LevelUp Diagnostic in benchmark mode, that time shows up alongside practice and will flatten a practice average if it is folded in.
Frequently asked questions
Is a SmartScore of 80 good?
Yes. 80 is IXL's own published threshold for proficiency in a skill. It is not mastery, which IXL reserves for 100.
What does a SmartScore of 100 mean?
IXL says a student who has earned 100 on a skill has mastered that topic.
Is a SmartScore the percentage of questions answered correctly?
No. IXL contrasts the SmartScore with percentage scoring specifically: a missed question is not a permanent deduction, and a student can recover within the same session.
Why did the SmartScore go down?
An incorrect answer lowers the SmartScore, and IXL says the questions that follow get easier.
Can a SmartScore be compared across two different skills?
Only loosely. Each skill is scored on its own, so 90 on one skill and 90 on another mean "close to excellence on this skill" twice, not one combined level.
How does the IXL SmartScore work?
It starts at 0 on each skill, rises with correct answers and falls with incorrect ones. IXL calculates it from factors including the number of questions completed, question difficulty and consistency, and questions get harder as the score rises.
How many questions does it take to get 80 on IXL?
IXL does not publish a number for 80 or 90. It says the number of questions varies with every student. The only count IXL gives is that reaching 100 from the Challenge Zone can take as many as 10 correct answers in a row.
What is the IXL Challenge Zone?
The stretch from a SmartScore of 90 to 100 in math and language arts skills, with the most difficult questions in the skill. Correct answers add 1 or 2 points there and incorrect answers cost 3 to 8 points.
Why does one wrong answer drop the score so much near 100?
Because IXL makes penalties larger in the Challenge Zone. Below 70, IXL says incorrect answers carry low penalties; from 90, they cost 3 to 8 points.
What does an IXL SmartScore of 70 mean?
IXL places 0 to 70 in its learning and practicing stage. The student is working on the skill and has not reached proficiency, which starts at 80.
Can a SmartScore go down after 100?
IXL's help pages do not say what happens if a student keeps practicing after 100. Its reports show "current score or prior mastery" by default, so a student who restarted a skill after mastering it still appears as 100 unless the SmartScore has been reset.
What does "prior mastery" mean in IXL reports?
It means the report shows 100 for a student who mastered the skill earlier, even if they restarted it since. A teacher can switch the Skill Score Chart to show the current school year only.
Sources
- IXL, The IXL SmartScore: the key to mastery-based learning. Source for the Challenge Zone's smaller gains and larger drops and why IXL designs it that way.
- IXL, How does the SmartScore work?. Source for the start at 0, the factors in the calculation, and the number of questions varying with every student.
- IXL, How the IXL SmartScore locks in learning (PDF). Source for the three stages, the 1 or 2 point gains, the 3 to 8 point penalties and as many as 10 correct answers in a row.
- IXL, What is the Challenge Zone?. Source for the third ribbon, the most difficult questions, saved progress and the gold medal.
- IXL, How can I use the Skill Score Chart?. Source for the Practiced group, prior mastery and resets.
- IXL, Can I set a SmartScore goal for skills I suggest to students?
- IXL, LevelUp vs Flex Diagnostic comparison
Lorsey is not affiliated with or endorsed by IXL Learning. IXL and SmartScore are trademarks of their respective owner, used here to describe the product a school already has.