What are the 4 types of contracts?

The 4 types of contracts most guides mean are express, implied, bilateral, and unilateral. Express contracts are stated in words, written or spoken. Implied contracts arise from behavior, like ordering food. Bilateral contracts trade promise for promise, and unilateral ones trade a promise for an act, like a reward offer.

You will also see the four main types sliced by form instead: written, verbal, standard form, and period contracts. Both lists are correct; they answer different questions.

For client work, the only type worth using is express and written. Verbal agreements can bind, but proving their terms is miserable. Put the scope, price, and dates on paper and the category question stops mattering.

A vetted legal contract template gives you the written kind with every essential clause in place.