Clear your doubts between BY and UNTIL

By and Until (“por” and “hasta”) are not interchangeable in English. Although their meaning is similar, we use them differently. By “por” introduces a deadline, while “hasta” gives information on when an action ends or a period of time.

Take a look at the examples below to learn more about when to use by and when to use until in English, then test your knowledge by practicing exercises.

Some examples of BY are

Please be home by 6:00 pm so we can eat dinner on time.”– This means that the latest you should be home is 6:00 pm.  This is a set deadline.
Por favor, llegue a casa a las 6:00 pm para que podamos cenar a tiempo. – Esto significa que lo más tarde que debe estar en casa es a las 6:00 pm. Este es un plazo establecido.

Every day Sean must be at work by 8:30 am or he will miss the daily morning budget meeting.– Sean can get to work earlier, but he must not get to work after 8:30 am because that is when the daily meeting begins.
Todos los días, Sean debe estar en el trabajo a las 8:30 am o se perderá la reunión diaria de presupuesto de la mañana. – Sean puede ir a trabajar más temprano, pero no debe hacerlo después de las 8:30 am porque es entonces cuando comienza la reunión diaria.

I must hand in my essay on Hemingway by Friday. – I need to finish writing my essay and give it to the teacher on or before Friday. This is a set deadline. “Until” is used to express how long a situation continues.
Debo entregar mi ensayo sobre Hemingway el viernes. – Necesito terminar de escribir mi ensayo y entregárselo al profesor el viernes o antes. Este es un plazo establecido. “Hasta” se usa para expresar cuánto tiempo continúa una situación.

Some examples of UNTIL are:

We have to stay at work until our boss comes back from the meeting. – This means that even if our boss returns after the workday should have ended, we must stay and wait for him.  If our usual work hours are 9:00 am – 5:00 pm, and he will return at 6:15 pm, we must stay in the office and wait for him.
Tenemos que quedarnos en el trabajo hasta que nuestro jefe regrese de la reunión. – Esto significa que incluso si nuestro jefe regresa después de que la jornada laboral debería haber terminado, debemos quedarnos y esperarlo. Si nuestro horario habitual de trabajo es de 9:00 am a 5:00 pm, y él regresará a las 6:15 pm, debemos quedarnos en la oficina y esperarlo.

Grandma said she will stay until it stops raining so she doesn’t get her hair wet.– Grandma doesn’t want to have wet hair, so she will stay wherever she is and wait for the rain to stop.  She will not leave before that happens.
La abuela dijo que se quedará hasta que deje de llover para no mojarse el pelo. – La abuela no quiere tener el pelo mojado, así que se quedará donde esté y esperará a que cese la lluvia. Ella no se irá antes de que eso suceda.

I will wait until they get here before I start cooking.– I will not start cooking before they get here, so after they arrive I will start cooking.
Esperaré hasta que lleguen antes de empezar a cocinar. – No empezaré a cocinar antes de que lleguen, así que después de que lleguen empezaré a cocinar.

The difference between “by” and “until”

Use “by” when referring to a deadline. “Until” means until a certain time.

Example:

• We have until Friday to send out the documents.
  Tenemos hasta el viernes para enviar los documentos.

You must use “until” when referring to the period of time before a deadline. While “by” should be used to describe an action or an event that occurs at or before a particular moment.

Example:

• We expect to know the judgment by the end of November.
  Esperamos conocer la sentencia a finales de noviembre.

“Until” is used to describe a state or situation in the period of time up to a particular moment.

Example:

• The court proceedings are expected to last until November.
  Se espera que los procedimientos judiciales duren hasta noviembre.

You can think of using “until” as a reference to when a state or situation changes.

Example:

• Comments on the draft may be submitted until 30 April 2012.
  Los comentarios sobre el borrador pueden enviarse hasta el 30 de abril de 2012.

In summary

It is true that by and until can be easily confused, however they are used differently and after a little study of this article, you should have no problem using them, keep in mind that By is used to mean “at the latest”. It is used as follows: by + (a time) to express this.