Dyscalculia vs dyslexia: what is the difference?
One affects numbers, the other reading and spelling. They often occur together, but they are different learning difficulties with different roots — and each needs its own screening and support.
Updated
Short answer
How do dyscalculia and dyslexia differ?
Dyslexia is a specific learning difficulty with reading and spelling, rooted mainly in processing speech sounds; dyscalculia is a specific learning difficulty with numbers, rooted in processing quantities. Both are classed as specific learning disorders, they often occur together, but research comparing children with one, the other or both shows different cognitive profiles. Dyscalculia is sometimes called "number dyslexia", yet it is a separate condition, so each needs its own screening and support; Dyscalculia.io's free test screens the number side only.
- Dyslexia: reading and spelling. Dyscalculia: numbers and calculation.
- Both are specific learning disorders in DSM-5.
- Co-occurrence is common but not the rule.
- Each needs targeted support for its own core skills.
3–7%
of children are estimated to have dyscalculia — a range similar to other specific learning disorders1
Common
co-occurrence: many children with one learning disorder also meet the criteria for another2
The key difference between dyscalculia and dyslexia
Dyslexia affects the link between letters and sounds, so reading is slow and spelling is hard. Dyscalculia affects the sense of quantity and the link between numbers and amounts, so counting, comparing and calculating are hard. A child with dyslexia may struggle with word problems because of the reading, while a child with dyscalculia struggles with the numbers themselves — even when the problem is read aloud.
Both are lasting difficulties that are out of step with a person's general ability and schooling. Dyscalculia is estimated to affect roughly 3 to 7 percent of children, and the difficulties usually continue into adulthood when they are not addressed. Read what dyscalculia is for the full picture.1,3,4
Dyscalculia vs dyslexia side by side
The table sets out the main differences between dyslexia and dyscalculia. The last row is the practical one: because the core skills differ, practice for one does not train the other.5,6
| Dyscalculia | Dyslexia | |
|---|---|---|
| Main area affected | Numbers, quantities and calculation | Reading and spelling |
| Core difficulty | Processing quantities and linking digits to amounts | Processing speech sounds and linking letters to sounds |
| Typical early signs | Counting small sets one by one, trouble saying which group has more | Trouble with rhymes, letter sounds and sounding out words |
| In daily life | Time, money, estimating, remembering number facts | Slow reading, spelling errors, avoiding reading aloud |
| Classification | Specific learning disorder with impairment in mathematics | Specific learning disorder with impairment in reading |
| How well known | Less known and less often identified | Widely known and more often identified |
| What to practise | Number sense: subitizing, comparison, number line, working memory for numbers | Phonological skills, decoding and reading fluency |
Is dyscalculia "number dyslexia"?
Dyscalculia is often searched for as "number dyslexia", "maths dyslexia" or "dyslexia with numbers". The terms are understandable — both are specific learning difficulties that make one kind of symbol hard to work with — but they are misleading. Dyscalculia is not a form of dyslexia, and a person can have either one without the other.
The difference matters in practice. Someone who is told they have "number dyslexia" may be offered reading support that does nothing for their number sense, or may assume that because their reading is fine, their maths difficulties must be about effort. Using the right name leads to the right screening and the right practice.5
How often dyscalculia and dyslexia occur together
Large studies of school children find that a substantial share of children with one learning disorder also meet the criteria for another. Dyscalculia and dyslexia together is common, yet many children have only one of them. Having one is a reason to look at the other, not a reason to assume it.
Co-occurrence also explains some confusion: a child with both may be identified for reading first, and the number difficulty is put down to reading problems in maths lessons. If maths stays hard when questions are read aloud, the number side deserves its own look.2,5
Different cognitive profiles of dyslexia and dyscalculia
Comparing children with dyslexia only, dyscalculia only and both, researchers found that dyslexia was linked to difficulties with speech-sound processing, while dyscalculia was linked to difficulties with basic number processing. Children with both showed both sets of difficulties, added together rather than a new pattern.
Other research on dyscalculia points to the same basic number skills: recognising small quantities at a glance, comparing numbers and judging which group of dots is larger. These are the skills a number-focused screening looks at.5,7,8
Signs of dyscalculia vs signs of dyslexia
Some signs point clearly to one or the other; a few appear in both, because maths lessons also involve reading and remembering sequences. For the full list by age, see the signs of dyscalculia.
Can dyslexia cause problems with maths?
Yes, indirectly. Reading word problems, following written instructions and remembering sequences can all be harder with dyslexia. If maths is still hard when everything is read aloud, the difficulty may lie with numbers themselves.
Does mixing up 12 and 21 mean dyslexia?
Not necessarily. Reversing digits and struggling with place value are common signs of number difficulties. It is one reason to check number skills directly rather than assume a reading problem.
Is dyscalculia rarer than dyslexia?
Estimates are in a similar range for both, but dyslexia is far better known and more often identified, so dyscalculia is easier to miss.
- Dyscalculia: trouble recognising small quantities, comparing numbers, remembering number facts, time and money.
- Dyslexia: slow, effortful reading, trouble sounding out words, frequent spelling errors.
- Both: word problems in maths, reading clocks, remembering sequences such as phone numbers or the days of the week.
Screening for dyscalculia and dyslexia
Because the conditions are separate, each needs its own screening. For numbers, the free dyscalculia test takes under 5 minutes and uses very little reading: the games show dots and digits, and the instructions can be read aloud to a child. A child with dyslexia but no number difficulty should not score low because of reading. Adults can take the dyscalculia test for adults.
If reading is also a concern, mention it when you ask for an assessment — a professional can assess both at once. See how dyscalculia is diagnosed for the steps.
Supporting dyscalculia alongside dyslexia
Support follows the core skill. Reading support works on sounds and decoding; number support works on quantities, comparison, the number line and working memory for numbers, in short and frequent sessions that move from objects to pictures to digits. A learner with both needs both, ideally with the number practice kept low on reading.
For hands-on ideas, see dyscalculia exercises. The Dyscalculia.io daily practice program runs five-minute number-sense sessions in the browser with minimal text, starting from the free test profile; the first 5 levels of each age world are free with an account.6