Experiments

Habit streak calculatorA streak is not the point.
The rate is.

Streaks are a good motivator and a bad measurement. They reset to zero on the day you were ill, which means a person who has done something 58 times out of 60 and a person who has done it 9 times both show a streak of nine — and only one of them has a habit.

Free, no sign-up. Worked out in your browser, nothing sent anywhere, and the result imports into EvyOS.

The start date needs to be in the past.

Everything is worked out in this page and saved in this browser only. Nothing is sent anywhere.

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✦ How to use it

Three things that make it work.

1
Count the whole period

From the day you started, including the days you missed. A rate calculated only over the good weeks is not a rate.

2
Watch doubles, not misses

One missed day costs almost nothing. Two in a row is where a habit actually breaks.

3
Treat the range as a range

Formation takes somewhere between two and eight months depending on the habit, and there is no twenty-one-day rule.

The rate is the honest number, and it is almost always higher than people think after a break. What actually matters is not whether you missed a day but whether you missed two in a row, which is the point where the pattern reverts rather than dips.

The formation estimate here is deliberately a range. The often-quoted twenty-one days comes from a plastic surgeon's observation about amputees adjusting to prosthetics and was never a finding about habits at all.

✦ The limit

An answer is not a record.

This works something out and then forgets it. It cannot tell you whether the number moved, because it has no memory of the last time you ran it and no idea what you did in between. Every calculator on the internet has that limit, and if it has never bothered you then this one is yours for free for good.

EvyOS is the same structure with the work recorded against it. Send the result across and it becomes real goals, tasks or habits with their dates — then the next answer is computed from what actually happened rather than from what you remember typing.

Questions

Habit streak calculator, answered.

No. That figure comes from a 1960 plastic surgeon's observation about how long amputees took to adjust to a prosthetic, and was never a finding about habits. The best study puts the median at 66 days with a range from 18 to 254, depending heavily on how demanding the behaviour is.
Because a streak resets to zero on the day you were ill. Someone who has done a thing 58 times out of 60 and someone who has done it 9 times can show the same streak of nine, and only one of them has a habit. The rate cannot be destroyed by a single bad day.
Almost irrelevant. Missing two in a row is the one that matters — that is where the pattern reverts rather than dips, which is why it is counted separately here.
The smallest thing that still counts: one page instead of ten, five minutes instead of thirty. Its whole job is to keep a bad day from becoming a double miss, and habits that have one survive travel and illness far better.
Send the habit across and EvyOS counts the streak and the rate itself, so the number is a record rather than a recollection.

Keep the answer.
And the record of doing it.

Goals, projects, tasks, habits and skills in one system, with the work logged against what it belonged to.

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