But if one defines Calvinism as belief in the "doctrines of grace," the five-point system of theology first articulated by the Synod of Dort, commonly known by the acronym TULIP (Total Depravity, Unconditional Election, Limited Atonement, Irresistable Grace, and Perseverance of the Saints), then there is no doubt that Spurgeon was a Calvinist.
Here is proof.
I have my own private opinion that there is no such thing as preaching Christ and Him crucified, unless we preach what nowadays is called Calvinism. It is a nickname to call it Calvinism; Calvinism is the gospel, and nothing else. I do not believe we can preach the gospel, if we do not preach justification by faith, without works; nor unless we preach the sovereignty of God in His dispensation of grace; nor unless we exalt the electing, unchangeable, eternal, immutable, conquering love of Jehovah; nor do I think we can preach the gospel, unless we base it upon the special and particular redemption of His elect and chosen people which Christ wrought out upon the cross; nor can I comprehend a gospel which lets saints fall away after they are called, and suffers the children of God to be burned in the fires of damnation after having once believed in Jesus. Such a gospel I abhor.
"If ever it should come to pass,
That sheep of Christ might fall away,
My fickle, feeble soul, alas!
Would fall a thousand times a day."
If one dear saint of God had perished, so might all; if one of the covenant ones be lost, so may all be; and then there is no gospel promise true, but the Bible is a lie, and there is nothing in it worth my acceptance. I will be an infidel at once when I can believe that a saint of God can ever fall finally. If God hath loved me once, then He will love me for ever. God has a master-mind; He arranged everything in His gigantic intellect long before He did it; and once having settled it, He never alters it, "This shall be done," saith He, and the iron hand of destiny marks it down, and it is brought to pass. "This is My purpose," and it stands, nor can earth or hell alter it. "This is My decree," saith He, "promulgate it, ye holy angels; rend it down from the gate of Heaven, ye devils, if ye can; but ye cannot alter the decree, it shall stand for ever." God altereth not His plans; why should He? He is Almighty, and therefore can perform His pleasure. Why should He? He is the All-wise, and therefore cannot have planned wrongly. Why should He? He is the everlasting God, and therefore cannot die before His plan is accomplished. Why should He change? Ye worthless atoms of earth, ephemera of a day, ye creeping insects upon this bay-leaf of existence, ye may change your plans, but He shall never, never change His. Has He told me that His plan is to save me? If so, I am for ever safe.
"My name from the palms of His hands
Eternity will not erase;
Impress'd on His heart it remains,
In marks of indelible grace."
Follow this link if you would like to read more of Spurgeon's "Defense of Calvinism".
[Note: I do have one caveat to make. I disagree slightly with Spurgeon's rhetoric, in that I do think a person can preach "the gospel" without ascribing to the full five-point system of Calvinism. I would define the gospel more narrowly than Spurgeon does, as essentially the substitutionary death of Christ for our sins and his resurrection from the dead, through which we are justified by faith. But the point of this post is just to show that Spurgeon made no bones about being a Calvinist.]