When making up missed days from Ramadan, if my intention is to fast those days without any interruption, i.e. to fast them consecutively, is it permissible to form one intention (niyyah) to fast all of these days?

Praise
be to Allah

Forming the
intention from the night before is a condition for every obligatory fast,
according to the most correct scholarly opinion, whether that fast is being
made up or is being offered on time.

This is
indicated by the words of the Prophet (blessings and peace of Allah be upon
him): “Whoever did not intend to fast before Fajr, there is no fast for
him.” Narrated by Abu Dawood (2454), at-Tirmidhi (730) and an-Nasaa’i
(2331). According to a version narrated by an-Nasaa’i: “Whoever does not
form the intention to fast during the night before Fajr, there is no fast
for him.”

This hadith was
classed as saheeh by al-Albaani in Saheeh Abi Dawood.

The majority of
fuqaha’ are of the view that it is obligatory to form the intention for each
day, and it is not sufficient to form the intention (only) at the beginning
of the month of Ramadan, or at the beginning of a period of consecutive
fasts for all of the days.

The Maalikis are
of the view that one niyyah (intention) is sufficient for a fast that must
be observed on consecutive days, such as Ramadan. As for a fast that does
not have to be observed on consecutive days, such as making up missed days
(qada’), it is essential to form a separate intention for each day.

It says in
al-Mawsoo‘ah al-Fiqhiyyah (40/275):

The Hanafis,
Shaafa‘is and Hanbalis are of the view that forgetting to form the intention
on some nights of a fast that must be observed on consecutive days
interrupts the sequence, as does omitting it deliberately, and forgetting is
not regarded as a valid excuse for failing to do what is obligatory.

The Maalikis are
of the view that a single intention is acceptable for every fast that must
be observed on consecutive days, such as Ramadan and expiatory fasts in
which the fast must be observed on consecutive days. End quote.

In al-Khulaasah
al-Fiqhiyyah ‘ala Madhhab as-Saadah al-Maalikiyyah, it says: A single
intention is sufficient for every fast which must be observed on consecutive
days, such as Ramadan and its expiation (i.e., the two-month expiatory fast
for having intercourse during the day in Ramadan); fasts in expiation for
murder or zihaar (a jaahili form of divorce in which a man says to his wife,
‘you are to me as my mother’s back’); and vows to observe a fast on
consecutive days, as in the case of one who vows to fast a specific month…
And it is essential to form the intention from the night before for each
fast that may be observed on separate days, such as making up missed days of
Ramadan, fasting whilst travelling, expiation for breaking an oath (kafaarat
yameen), fasting in expiation for shaving the head whilst in ihram due to an
ailment in the scalp, or fasting to make up for some shortcoming in
performing the rituals of Hajj. End quote.

Based on that:

If you intended
to make up the Ramadan fasts on consecutive days, then you must form the
intention for each day, according to the majority of scholars. I put this
question to our shaykh, ‘Abd ar-Rahmaan al-Barraak (may Allah preserve him),
and he replied:

The intention
must be formed for each day. Offering fasts to make up for missed days is
not like fasting in Ramadan, according to those scholars who allow forming a
single intention (for the entire month), because the days of Ramadan are
consecutive as enjoined by Allah. End quote.

However, we
should point out that if someone thinks to himself that he will be fasting
tomorrow, then he has formed the intention. Shaykh al-Islam Ibn Taymiyah
(may Allah have mercy on him) said: Whoever thinks to himself that he will
be fasting tomorrow has indeed formed the intention of doing so. End quote
from al-Ikhtiyaaraat al-Fiqhiyyah, in al-Fataawa al-Kubraa
(4/459).

And Allah knows
best.