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Anki assigns wrong interval

I set my new cards both Easy and Graduating Interval to 3 days. I also have set lapses minimum interval to 3 days. However, for new cards after clicking easy which is supposed to have 3 days interval, Anki assigns varying intervals from 2 to 4 days. The same problem applies to review card that have lapsed. I am not sure if this is a bug or I am doing something wrongly? I am on Anki 2.1.26. Attached is an example of a new card which is supposed to have 3 day interval after clicking easy but Anki assigns 2 days instead.

When you press a button that say 30 days, anki might give the card a different interval. it’s due to fuzz factor and doesn’t mean anki’s algorithm is broken or it’s not functioning properly.
anki automatically applies a fuzz factor to all cards so when you introduce some new cards, you won’t have to review all of them in the same day.

The fuzz factor is usually between 15 to 20 percent.

Example

Here’s an example for you to understand fuzz factor better

Interval for card A: 10 days (on any button)
interval for card B: 20 days (on any button)
interval for card C: 30 days (on any button)
interval for card D: 40 days (on any button)

Now here’s the interval that we expect anki to give these cards:

for card A the interval should be something from 8 to 12 days
for card B the interval should be something from 16 to 24 days
for card C the interval should be something from 25 to 35 days
for card D the interval should be something from 34 to 46 days

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