Contracts 101: Make a Legally Valid Contract

All you need is a clear agreement and mutual promises to exchange things of value.

By , Attorney · UC Law San Francisco

Lots of contracts are filled with mind-bending legal gibberish, but there's no reason why this has to be true. For most contracts, legalese is not essential or even helpful. On the contrary, the agreements you'll want to put into a written contract are best expressed in simple, everyday English.

Most contracts only need to contain two elements to be legally valid:

  • All parties must be in agreement (after an offer has been made by one party and accepted by the other).
  • Something of value must be exchanged -- such as cash, services, or goods (or a promise to exchange such an item) -- for something else of value.

Does a contract have to be in writing? In a few situations, contracts must be in writing to be valid. State laws often require written contracts for real estate transactions or agreements that will last for more than one year. You'll need to check your state's laws to determine exactly which contracts must be in writing. But even if it's not legally required, it's always a good idea to put business agreements in writing, because oral contracts can be difficult or impossible to prove.

Let's take a closer look at the two required contract elements: agreement between the parties, and exchange of things of value.

Agreement Between the Parties

Although it may seem like stating the obvious, an essential element of a valid contract is that all parties must agree on all major issues. In real life, there are plenty of situations that blur the line between a full agreement and a preliminary discussion about the possibility of making an agreement. To help clarify these borderline cases, the law has developed some rules defining when an agreement legally exists.

Offer and Acceptance

The most basic rule of contract law is that a legal contract exists when one party makes an offer and the other party accepts it. For most types of contracts, this can be done either orally or in writing.

Let's say, for instance, you're shopping around for a print shop to produce brochures for your business. One printer says (or faxes, or emails) that he'll print 5,000 of your two-color flyers for $300. This constitutes his offer.

If you tell the printer to go ahead with the job, you've accepted his offer. In the eyes of the law, when you tell the printer to go ahead you create a contract, which means you're liable for your side of the bargain (in this case, the payment of $300). But if you tell the printer you're not sure and want to continue shopping around (or don't even respond, for that matter), you haven't accepted the offer, and no agreement has been reached.

But if you tell the printer the offer sounds great except that you want the printer to use three colors instead of two, no contract has been made. This is because you have not accepted all of the important terms of the offer. You have actually changed one term of the offer. (Depending on your wording, you have probably made a counteroffer, which is discussed below.)

When Acceptance Occurs

In day-to-day business, the seemingly simple steps of offer and acceptance can become quite convoluted. For instance, sometimes an offer isn't quickly and unequivocally accepted; the other party may want to think about it for a while, or try to get a better deal. And before the other party accepts your offer, you might change your mind and want to withdraw or amend it. Delaying acceptance of an offer and revoking an offer, as well as making a counteroffer, are common situations that may lead to confusion and conflict. To minimize the potential for a dispute, here are some general rules you should understand and follow.

How Long an Offer Stays Open

Unless an offer includes a stated expiration date, it remains open for a "reasonable" time. What's reasonable, of course, is open to interpretation and will vary depending on the type of business and the particular fact situation.

To leave no room for doubt as to when the other party must make a decision, the best way to make an offer is to include an expiration date.

If you want to accept someone else's offer, the best approach is to do it as soon as possible, while there's no doubt that the offer is still open. Keep in mind that until you accept, the person or company who made the offer -- called the offeror -- may revoke the offer.

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