Anki desired retention: what 90% means and how to choose

Desired retention is the main setting in FSRS, Anki's newer scheduler. It's the chance that you'll remember a card when it comes due. At the default of 90%, Anki schedules each card for the day it predicts your recall will have dropped to 90%, so you should pass about 9 reviews in 10 and fail about 1. Raise it and intervals get shorter and reviews go up; lower it and you review less but forget more.

Where it is

Desired retention only exists when FSRS is on. Turn FSRS on at the bottom of Deck Options; it applies to every preset at once. How to turn on FSRS in Anki has the steps for each device. The desired retention value itself is per preset, and recent versions of Anki also let you set it per deck. With FSRS off, Anki uses SM-2 and this setting isn't shown.

What changing it does

The trade isn't even. Anki's manual says the workload rises quickly above 90% and can become overwhelming above 97%, and recommends staying below 97%.

• Higher (say 95%). You forget less, but you do noticeably more reviews for each point gained.
• Lower (say 85%). Fewer reviews, more forgotten cards. Every failed card goes back through relearning, so very low values stop saving time.

Most people should leave it at 90%. Move it if you have a reason: a high-stakes exam might justify a few points more, and a hobby deck you'd rather spend less time on might justify a few points less.

Help me decide

Recent versions of Anki include a simulator (Help Me Decide) that estimates your reviews or minutes per day at different retention values, using your own cards and history. Ask yourself how many minutes a day you can actually spend, and pick the retention that fits. The older Compute minimum recommended retention button was removed in Anki 25.07.

Changing it doesn't move your cards right away

By default, a new desired retention only affects future scheduling. Cards keep their current due dates until you next review them. The Reschedule cards on change option moves them immediately, which can make a lot of cards due at once; Anki's manual doesn't recommend it when you first switch from SM-2.

One habit FSRS can't handle

Press Again when you've forgotten a card. FSRS treats Hard as a pass, so using Hard for "I didn't know it" makes it think you remember more than you do, and your intervals grow too long. See Hard vs Again.

The SM-2 equivalent

SM-2 has no retention target. The closest control is the interval modifier, which scales every interval by a fixed amount; Anki interval modifier explains how to calculate it. SM-2 vs FSRS compares the two schedulers.

In Decks

Decks uses SM-2, so it has no desired retention setting. If you want to choose a retention target, use Anki with FSRS.