The use of contraception is intrinsically evil and always gravely immoral:
Pontifical Council for the Family: “The Church has always taught the intrinsic evil of contraception, that is, of every marital act intentionally rendered unfruitful. This teaching is to be held as definitive and irreformable. Contraception is gravely opposed to marital chastity; it is contrary to the good of the transmission of life (the procreative aspect of matrimony), and to the reciprocal self-giving of the spouses (the unitive aspect of matrimony); it harms true love and denies the sovereign role of God in the transmission of human life.” (Vademecum for Confessors, n. 4)
Pope Pius XI: “But no reason, however grave, may be put forward by which anything intrinsically against nature may become conformable to nature and morally good. Since, therefore, the conjugal act is destined primarily by nature for the begetting of children, those who in exercising it deliberately frustrate its natural power and purpose sin against nature and commit a deed which is shameful and intrinsically vicious.” (Casti Connubii, n. 54)
Pope Pius XII: “Our Predecessor, Pius XI, of happy memory, in his Encyclical Casti Connubii, of December 31, 1930, once again solemnly proclaimed the fundamental law of the conjugal act and conjugal relations: that every attempt of either husband or wife in the performance of the conjugal act or in the development of its natural consequences which aims at depriving it of its inherent force and hinders the procreation of new life is immoral; and that no ‘indication’ or need can convert an act which is intrinsically immoral into a moral and lawful one.” (Address to Midwives)
Pope Paul VI: “Consequently, it is a serious error to think that a whole married life of otherwise normal relations can justify sexual intercourse which is deliberately contraceptive and so intrinsically wrong.” (Humanae Vitae, n. 14)
Compendium of the Catechism: “What are immoral means of birth control? Every action — for example, direct sterilization or contraception — is intrinsically immoral which (either in anticipation of the conjugal act, in its accomplishment or in the development of its natural consequences) proposes, as an end or as a means, to hinder procreation.” (Compendium, n. 498)
Cardinal Stafford: “the unitive and procreative meanings of marriage cannot be separated. Consequently, to deprive a conjugal act deliberately of its fertility is intrinsically wrong.” (Francis Cardinal Stafford, Major Penitentiary of the Apostolic Penitentiary, speech to American Academy of Fertilitycare Professionals, 11 June 2008)
Pope John Paul II: “This is the reason for the intrinsic unlawfulness of contraception: it introduces a substantial limitation into this reciprocal giving, breaking that ‘inseparable connection’ between the two meanings of the conjugal act, the unitive and the procreative, which, as Pope Paul VI pointed out, are written by God himself into the nature of the human being (n. 12).” (Speeches, 27 Feb. 1998)
Pope John Paul II: “With regard to intrinsically evil acts, and in reference to contraceptive practices whereby the conjugal act is intentionally rendered infertile, Pope Paul VI teaches: ‘Though it is true that sometimes it is lawful to tolerate a lesser moral evil in order to avoid a greater evil or in order to promote a greater good, it is never lawful, even for the gravest reasons, to do evil that good may come of it (cf. Rom 3:8) – in other words, to intend directly something which of its very nature contradicts the moral order, and which must therefore be judged unworthy of man, even though the intention is to protect or promote the welfare of an individual, of a family or of society in general’.” (Veritatis Splendor, n. 80; inner quote from Humanae Vitae, n. 14).
Intrinsically evil acts are never justified by intention (purpose) or circumstances.
The Catechism of the Catholic Church: “Legitimate intentions on the part of the spouses do not justify recourse to morally unacceptable means (for example, direct sterilization or contraception).” (CCC, n. 2399).
Catechism of the Catholic Church: “It is therefore an error to judge the morality of human acts by considering only the intention that inspires them or the circumstances (environment, social pressure, duress or emergency, etc.) which supply their context. There are acts which, in and of themselves, independently of circumstances and intentions, are always gravely illicit by reason of their object; such as blasphemy and perjury, murder and adultery. One may not do evil so that good may result from it.” (CCC, n. 1756)
Pope Pius XI: “But no reason, however grave, may be put forward by which anything intrinsically against nature may become conformable to nature and morally good.” (Casti Connubii, n. 54.)
Pope John Paul II: “If acts are intrinsically evil, a good intention or particular circumstances can diminish their evil, but they cannot remove it. They remain irremediably evil acts; per se and in themselves they are not capable of being ordered to God and to the good of the person…. Consequently, circumstances or intentions can never transform an act intrinsically evil by virtue of its object into an act ‘subjectively’ good or defensible as a choice.” (Veritatis Splendor 81)
Pope John Paul II: “No circumstance, no purpose, no law whatsoever can ever make licit an act which is intrinsically illicit, since it is contrary to the Law of God which is written in every human heart, knowable by reason itself, and proclaimed by the Church.” (Evangelium Vitae 62)
The above teaching of the Roman Catholic Church is infallible under the ordinary and universal Magisterium.
May God rebuke the many false teachers and anonymous online commentators who say otherwise.