Short answer: Habit stacking means attaching a new habit to something you already do every day, using the formula ‘after I [current habit], I will [new habit]’. For example: after I put the kettle on, I will do two minutes of stretching. The existing habit becomes the prompt, so you don’t have to remember. Keep the new habit to two minutes at first.
Most new habits don’t fail because people don’t care. They fail because the moment passes. You meant to stretch, or read, or send the message, and then it was eleven at night.
Habit stacking fixes the remembering problem. Instead of relying on a free moment turning up, you tie the new habit to one that already happens every day, whatever kind of day it is.
What is habit stacking?
It is a way of planning a new habit so that something you already do sets it off. GROWTH by DESIGN puts it in one line worth writing out in full: after I ___, I will ___.
- After I put the kettle on, I will do two minutes of stretching.
- After I send the last email of the day, I will write tomorrow’s one job on a sticky note.
- After I brush my teeth, I will read one page.
Your existing routine is scaffolding you have already built. Habit stacking puts it to use.
Why does habit stacking work?
Because habits are made by repeating something in the same setting until the setting starts the behaviour for you. That is how Gardner, Lally and Wardle describe habit formation in their paper for GPs: repetition in a consistent context, until the context prompts the action without much thought.
A daily habit you already have is the most consistent context you own. The kettle goes on every morning. The teeth get brushed every night.
There is also good evidence for the ‘after I, I will’ shape itself. Plans written as if-then statements are called implementation intentions. A review of 94 tests by Gollwitzer and Sheeran found they had a medium-to-large effect on whether people reached their goals. Deciding when and where in advance takes the decision out of the moment, when you are tired and it is easiest to skip.
BJ Fogg’s behaviour model makes the same point from another angle: behaviour happens when motivation, ability and a prompt come together. Stacking supplies the prompt. Keeping the new habit tiny takes care of ability.
How do I choose the right anchor habit?
A good anchor has four things.
- It happens every day. Including weekends and bad days. Brushing your teeth qualifies. Going to the gym does not.
- It happens at the right time. Stretching fits after the kettle. Reading fits after getting into bed. Match the new habit to the moment it suits.
- It has a clear end. ‘After I finish my coffee’ is clearer than ‘in the morning’. The new habit needs a precise starting gun.
- It happens in the right place. If the new habit needs something, a book or a mat, it should be within reach of the anchor.
If you are not sure what your anchors are, write down everything you do between waking and leaving the house, and between getting home and going to bed. Most people find ten or more.
What if the habit stack doesn’t stick?
Shrink the new habit first. If it takes longer than two minutes, the stack is carrying too much. Two minutes of the thing is the plan to begin with. It can grow later.
If it still doesn’t happen, GROWTH by DESIGN names three causes, and all three can be fixed:
- The anchor is wrong. The moment never announces itself. Pick an anchor with a sharper end.
- The step is still bigger than it looks. Halve it again.
- The change isn’t yours. You are doing it because you think you should. It is worth going back to why you picked it.
A missed day is not a reason to start over. In the same GP paper, missing the occasional day did not seriously set people back. Do the smallest version at the next anchor, and carry on.
The bad-day version. On a bad day, keep the anchor and shrink the habit. After I put the kettle on, I will do one stretch. The link between the two is the thing worth protecting.
Can I stack more than one habit?
Yes, once the first one runs on its own. A chain can build up over months: kettle on, two minutes of stretching, then write the day’s one job. But add one link at a time. A new chain of four habits on day one is four chances for it to break, and one break tends to bring down the rest.
Frequently asked questions
What is habit stacking?
Habit stacking means attaching a new habit to one you already do every day, using the formula ‘after I [current habit], I will [new habit]’. The existing habit acts as the prompt, so you don’t have to remember the new one.
What are some examples of habit stacking?
After I put the kettle on, I will do two minutes of stretching. After I send the last email of the day, I will write tomorrow’s one job down. After I brush my teeth at night, I will read one page.
Does habit stacking work?
It is built on two well-supported ideas. Habits form by repeating a behaviour in the same context, and if-then plans, called implementation intentions, had a medium-to-large effect on goal attainment across 94 tests.
How do I pick a good anchor habit?
Choose something you do every day, including bad days, at the right time for the new habit, with a clear end point, in the place where the new habit happens. Brushing your teeth and putting the kettle on are common anchors.
Read next: How to build a habit when you’re exhausted and How long does it take to form a habit? What the research found.
Want to plan the whole change, not only the first habit? The free One-Page Change Plan puts the six DESIGN steps on one printable sheet. It comes with three other free tools.