A particular Latin formula and its English translations
Within the Catholic Church, the term "act of contrition" is often applied to one particular formula, which is not given expressly in the handbook of Indulgences.
The Catechism of the Catholic Church notes that "Among the penitent’s acts, contrition occupies first place. Contrition is 'sorrow of the soul and detestation for the sin committed together with the resolution not to sin again.' When it arises from a love by which God is loved above all else, contrition is called ‘perfect’ (contrition of charity). Such contrition remits venial sins; it also obtains forgiveness of mortal sins if it includes the firm resolution to have recourse to sacramental confession as soon as possible" (CCC 1451–1452).
The Latin text and a number of English versions that approximate to the Latin text are given here.
Deus meus, ex toto corde paenitet me omnium meorum peccatorum,
eaque detestor, quia peccando,
non solum poenas a te iuste statutas promeritus sum,
sed praesertim quia offendi te,
summum bonum, ac dignum qui super omnia diligaris.
Ideo firmiter propono,
adiuvante gratia tua,
de cetero me non peccaturum peccandique occasiones proximas fugiturum.
The following are some formulas for acts of contrition that differ more considerably from the Latin text given above.
My Lord, I am heartily sorry for all my sins,
help me to live like Jesus and not sin again.
My God, I am sorry for my sins with all my heart.
In choosing to do wrong, and failing to do good, I have sinned against You,
whom I should love above all things.
I firmly intend, with Your help, to do penance, to sin no more,
and to avoid whatever leads me to sin.
Oh my God, I am sorry that I have sinned against you.
Because you are so good, and with your help,
I will try not to sin again.
Oh My God, because you are so good,
I am very sorry that I have sinned against you,
and by the help of your grace, I will try not sin again.
O my God, I am sorry for my sins. In choosing to sin, and failing to do good, I have sinned against You and Your Church. I firmly intend, with the help of Your Son, to do good and to sin no more. Amen.
O my God, I am very sorry for all my sins because they offend You, Who are so good, and with Your help, I will not sin again. Amen.
Anglican General Confession
The Anglican Communion, which includes the Church of England, The Episcopal Church (in the United States) and other member churches, has its own act of contrition, referred to in the Prayer Book as the General Confession. This is said by the Congregation en masse during regular worship services. The original form in the 1662 Book of Common Prayer is:
ALMIGHTY and most merciful Father;
We have erred, and strayed from thy ways like lost sheep.
We have followed too much the devices and desires of our own hearts.
We have offended against thy holy laws.
We have left undone those things which we ought to have done;
And we have done those things which we ought not to have done;
And there is no health in us.
But thou, O Lord, have mercy upon us, miserable offenders.
Spare thou them, O God, which confess their faults.
Restore thou them that are penitent; According to thy promises declared unto mankind in Christ Jesu our Lord.
And grant, O most merciful Father, for his sake; That we may hereafter live a godly, righteous, and sober life, To the glory of thy holy Name. Amen.
Modernized forms can be found in other Anglican Prayer Books.