fixed costs vs fixed cost

fixed costs and fixed cost both are nouns.

Word	Noun	Adjective	Verb	Adverb
fixed costs	Yes	No	No	No
fixed cost	Yes	No	No	No

As nouns, fixed costs and fixed cost are synonyms defined as:

fixed costs and fixed cost: a periodic charge that does not vary with business volume (as insurance or rent or mortgage payments etc.)

Other synonyms of fixed costs include fixed charge.

fixed costs (noun)	fixed cost (noun)
a periodic charge that does not vary with business volume (as insurance or rent or mortgage payments etc.)	a periodic charge that does not vary with business volume (as insurance or rent or mortgage payments etc.)