The Ebbinghaus Forgetting Curve: How to Learn Spelling Words Without Forgetting Them a Week Later

2026-09-22

The spelling list is learned, Friday's test goes well. Two weeks later, in a piece of writing, the same words are wrong again. Same story with vocabulary for any subject: everything known the night before, nothing left the week after.

Your child isn't lazy. Every brain works this way. The first person to measure it was a German psychologist, Hermann Ebbinghaus, and the result carries his name: the forgetting curve.

What Ebbinghaus found

Ebbinghaus memorised lists of meaningless syllables and then measured how much he could recall as the hours and days passed. The result:

Immediately after learning: 100%
After 20 minutes: around 40% forgotten
After an hour: about half gone
After a day: around 70% forgotten
After that, the forgetting slows down

In other words, most of what's just been learned disappears within 24 hours. That's why revising the night before works on the day of the test and leaves nothing behind.

Spaced repetition: revise just before you forget

Ebbinghaus made a second discovery, and it's the useful one: if you revise at the point where you're about to forget, the curve climbs back up — and then falls more slowly. Each revision slows the forgetting. After a few, you barely forget at all.

That's spaced repetition. The idea is simple:

Instead of one long session, several short ones, spaced further and further apart.

For the same total time, fifteen minutes on four days leaves far more behind than an hour the night before.

A timetable that fits primary school

The intervals used in research are complicated. For spelling lists and vocabulary, this is enough:

Session	When	What
1	The day the list arrives	Read aloud, copy once
2	The next day	List covered, write from dictation
3	Two days later	Only the words that went wrong
4	The night before the test	The whole list, as in class
5	Two to three weeks later	That list, mixed with the current week's

It fits the usual rhythm well: list on Monday, test on Friday. Sessions 1–4 for this week's list, session 5 for the one from two weeks ago.

What that looks like in a week

Monday: the list arrives. You read it, your child repeats and copies it once. (10 min)

Tuesday: list covered. You dictate (or the app does), your child writes. Wrong words get a tick. (10 min)

Thursday: just the ticked words. Ones that are now right lose their tick. (5 min)

Thursday evening or Friday morning: the whole list, under test conditions. (10 min)

Some day the following week: last week's list, once. This is the session almost nobody does — and it's the one that makes the difference by the end of term. (5 min)

Forty minutes in total. The same as one forty-minute session the night before, with a result that isn't comparable.

For vocabulary in other languages

The same timetable works for French, Mandarin or any vocabulary test, with one difference: where the link between sound and spelling is irregular, the child has to hear the word at each revision, not just read it.

Day 1: listen, repeat, write once with the meaning
Next day: listen only, write the spelling
Two days later: the wrong ones
Before the test: all of them

The card box: spaced repetition that runs itself

Remembering the revision timetable is one more thing to carry. A card box carries it for you.

Each word that goes wrong is written on a card.
The box has three sections: every day / every 3 days / every week.
A new card goes into "every day".
Word right → the card moves forward one section. Word wrong → back to "every day".

Words that are known get seen less and less; difficult words keep coming back. Spaced repetition happens by itself.

An app does the same thing more simply. In DictationEasy, each week's list stays saved: your child can redo it alone from dictation, and pull up the list from two weeks ago for session 5 — the one that always gets forgotten.

Three things worth keeping in mind

Forgetting is not failure. A word forgotten and re-learned is better fixed than a word learned once. If your child gets last week's word wrong, don't scold — that is precisely the moment to revise it.
Short and often. Beyond ten minutes, a Year 1 or Year 2 child's attention drops off.
The first two days matter most. The day the list arrives, and the next. Those two sessions alone give half the result.

Frequently Asked Questions

Does the forgetting curve apply to children?

Yes. It describes how human memory works at any age. Primary-school children are actually a good case: little content to hold, and a regular weekly rhythm that suits spaced repetition.

Do the intervals have to be followed exactly?

No. A day or two either way changes nothing. What matters is not doing it all in one go, and looking at the list again the day after it arrives.

How many minutes a day?

Ten in Years 1–2, fifteen from Year 3 on. Beyond that, attention drops and the extra time adds almost nothing.

If the test went well, do we still need to revise afterwards?

Yes. A good mark on Friday is short-term memory. Without a revision two or three weeks later, a good proportion of the words goes. Five minutes on the previous week's list is enough.

Does this work for times tables and other facts too?

Yes — for anything that has to be remembered long-term: tables, dates, vocabulary, poems. The principle is the same: revise a little, often, at growing intervals.