The difference between Essential and Indispensable

When used as nouns, essential means a necessary ingredient, whereas indispensable means a thing that is not dispensable.

When used as adjectives, essential means necessary, whereas indispensable means not admitting ecclesiastical dispensation.

check bellow for the other definitions of Essential and Indispensable

Essential as an adjective:

Necessary.
Essential as an adjective:

Very important; of high importance.
Essential as an adjective (biology):

for survival but not by the organism, thus needing to be ingested
Essential as an adjective:

Being in the basic form; showing its essence.

Examples:

"Don’t mind him being grumpy. That’s the essential Fred."
Essential as an adjective:

Really existing; existent.
Essential as an adjective (of a [[lamination]] of a 3-[[manifold]]):

Such that each complementary region is irreducible, the boundary of each complementary region is incompressible by disks and monogons in the complementary region, and no leaf is a sphere or a torus bounding a solid torus in the manifold.

Examples:

"rfex difference between 1 and 2"
Essential as an adjective (medicine):

Idiopathic.

Indispensable as an adjective (ecclesiastical, obsolete):

Not admitting ecclesiastical dispensation; not subject to release or exemption; that cannot be allowed by bending the canonical rules.
Indispensable as an adjective (of duties, rules etc.):

Unbendable, that cannot be set aside or ignored.

Examples:

"The law was moral and indispensable.'' -Bp. Burnet"
Indispensable as an adjective:

Absolutely necessary or requisite; that one cannot do without.

Examples:

"An indispensable component of a heart-healthy diet."

Indispensable as a noun:

A thing that is not dispensable; a necessity.
Indispensable as a noun (in the plural, colloquial, dated):

Trousers.