What canon law says about Mass intentions, in the order a parish office meets it
The rules are short and live in canons 945 to 958 of the Code of Canon Law. Quotes below are from the English text on vatican.va. Your diocese's own decrees come on top (the offering amount, where bination offerings go, how unsatisfied Masses are handed over); ask your chancery for them.
Taking the intention
Can. 948 Separate Masses are to be applied for the intentions of those for whom a single offering, although small, has been given and accepted.
Can. 953 No one is permitted to accept more offerings for Masses to be applied by himself than he can satisfy within a year.
The amount is set by the bishops of the province or by diocesan custom, and a priest may not ask for more, though he may accept a voluntary offering that is larger or smaller (c. 952). A sum given with no number of Masses is divided by the offering where the donor lives (c. 950).
The one-year clock
Can. 955 §2. The time within which Masses must be celebrated begins on the day the priest who is to celebrate them received them unless it is otherwise evident.
Can. 956 ... are to hand over to their ordinaries according to the method defined by the latter the Mass obligations which have not been satisfied within a year.
A second Mass the same day
Can. 951 §1. A priest who celebrates several Masses on the same day can apply each to the intention for which the offering was given, but subject to the rule that, except on Christmas, he is to keep the offering for only one Mass and transfer the others to the purposes prescribed by the ordinary, while allowing for some recompense by reason of an extrinsic title. §2. A priest who concelebrates a second Mass on the same day cannot accept an offering for it under any title.
Passing intentions on
Can. 954 If in certain churches or oratories more Masses are asked to be celebrated than can be celebrated there, it is permitted for them to be celebrated elsewhere unless the donors have expressly indicated a contrary intention.
Can. 955 §1. ... He must transfer the entire offering received unless it is certain that the excess over the sum fixed in the diocese was given for him personally.
The book
Can. 958 §1. The pastor and the rector of a church or other pious place which regularly receives offerings for Masses are to have a special book in which they note accurately the number of Masses to be celebrated, the intention, the offering given, and their celebration. §2. The ordinary is obliged to examine these books each year either personally or through others.
A worked example
A made-up parish (the example book the tool loads) on 3 November 2026, with $10 as the diocesan offering:
| Entry | What the book shows | Canon |
|---|---|---|
| Two intentions from the same family, each with $10, on the 7 November 8:00 Mass | Two offered intentions on one Mass: give each its own Mass | 948 |
| $20 received for intention 2026-102, $10 sent to a missionary priest | The whole offering should go, unless the extra $10 was certainly a personal gift | 955 §1 |
| Intention received 20 October 2025, never booked | 14 days past a year: goes to the ordinary as he directs | 956 |
| Intention received 25 November 2025, not booked | Reaches a year in 22 days | 955 §2 |
Pressing "Book open intentions" then puts the anniversary intention on the Sunday it asked for, puts the next oldest on the first free Mass (Saturday at 17:00, which clears its one-year warning), and leaves the one past a year for the ordinary instead of quietly booking it. If that puts offered intentions on two of the pastor's Masses on one Saturday, the book adds a c. 951 §1 note: one offering kept, the other passed to the purposes the ordinary sets.
Short answers
How long can a parish hold a Mass intention before it must be said?
A year. Canon 953 forbids accepting more offerings than one can satisfy within a year, and canon 956 has obligations not satisfied within a year handed to the ordinary. Canon 955 §2 starts the time on the day the priest received them unless it is otherwise evident.
What happens to the offering when a priest says two Masses in one day?
Except on Christmas he keeps the offering for only one Mass and transfers the others to the purposes prescribed by the ordinary (c. 951 §1). If he concelebrates the second Mass he cannot accept an offering for it under any title (c. 951 §2).
What must the parish Mass book record?
The number of Masses to be celebrated, the intention, the offering given, and their celebration (c. 958 §1). The ordinary examines these books each year (c. 958 §2).
What the tool does not check
Collective (plurintentional) Masses under the Congregation for the Clergy's 1991 decree, foundation Masses, the Mass the pastor applies for the people, the extrinsic-title recompense, and any diocesan particular law. It reads only what you type.