Past Tense of Fit

The past tense of fit can cause some confusion between whether it is right to use 'fit' or 'fitted'.

First it is important to understand the meaning of fit as a verb because it has three principal uses.

Meaning of the Verb 'to Fit'

To be the right size or shape:

This dress fits me really well
This wardrobe won't fit through the door
My car won't fit in that space

To be suitable for something:

The punishment should fit the crime
She fits into her new role work perfectly
This new office space fits the requirements of our company

To provide something and put it in position:

Top Carpets Ltd fit your carpets for free
My dentist will fit my braces tomorrow
They are fitting smoke alarms into their home

Past Tense of Fit

What you use for the past tense of fit depends on whether you are using the general American English derived version or the British English one.

In American English, the standardised usage is fit. However, in British English, there is more division over the use of fit or fitted, though fitted tends to be the version that is preferred or used more often. So this is how it may vary:

"The business suit that I tried on yesterday fit perfectly"

"The business suit that I tried on yesterday fitted perfectly"

American English (fit)

That dress that I tried on yesterday fit me perfectly
The new office space that they found fit their requirements
They fit smoke alarms into their home three years ago

British English (fitted)

That dress I tried on yesterday fitted me perfectly
The new office space that they found fitted their requirements
They fitted smoke alarms into their home three years ago

It's important though to remember that these are not fixed rules and you may get different people making different choices for the past simple of fit, irrespective of the words history.

Other Tenses

These guidelines for the past tense of fit also apply to the past participle used in the perfect tense. So, in American English, there is a preference for fit:

The punishment should have fit the crime
The company has just fit my carpets

Or in British English:

The punishment should have fitted the crime
The company has just fitted my carpets

Adjectives

When you are thinking about the past simple of fit, don't get it mixed up with adjectives where the words can have a different meaning:

She is very fit (healthy)
He is a perfect fit for the job (suitable)
I've met a guy I think is really fit! (attractive)

But fitted as an adjective is also possible, but this is to indicate something that is designed to fit:

He is wearing a fitted suit

Summary

So the general differences between fit and fitted in the past tense are:

American English = fit is used
British English = fitted is used

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