By vs With: Who Did It, and What Did They Use?

"The cake was made with my grandmother." Wait, was your grandmother the baker, or was she one of the ingredients? Welcome to the by vs with problem, where a single preposition decides whether your sentence is touching or accidentally horrifying.

Quick Answer

By tells you who did something or how it happened at a method level (transport, payment, channel). With tells you what tool was used or who came along. If you can answer "by whom?" — use by. If you can answer "using what?" or "alongside whom?" — use with.

The Simple Rule

  • By = agent ("The novel was written by Murakami") and method ("I came by train," "I'll pay by card," "Reach me by email").
  • With = instrument or tool ("Cut it with scissors," "She wrote with a pencil") and accompaniment ("I went with a friend").

Quick mental test: if removing the preposition turns the noun into a doer, use by. If the noun is a thing being used or a companion, use with.

Natural Examples

Agent (the doer) — by

  • The painting was finished by a student.
  • This song was written by a teenager.
  • The window was broken by the storm.

Method of transport, payment, communication — by

  • I usually go to work by bike.
  • Can I pay by card?
  • Just send the document by email.
  • She contacted me by phone.

Tool or instrument — with

  • He opened the bottle with a coin.
  • She drew the diagram with a red pen.
  • I cleaned the screen with a soft cloth.

Accompaniment — with

  • I had dinner with my parents.
  • He arrived with two enormous suitcases.
  • She left the party with a headache. (Not literally a companion, but the same accompaniment pattern.)

The interesting case: pay by vs pay with

Both of these are correct, and natives use both:

  • "I paid by credit card." — talks about the method of payment, like checking a box on a form.
  • "I paid with my credit card." — talks about the physical instrument you used at that moment.

In careful business writing and on forms, by sounds slightly more formal and abstract ("Payment by card accepted"). In everyday spoken English, with sounds more concrete ("I'll just pay with my card"). Both are natural. This is one of the few places where the line between by and with genuinely softens.

Common Mistakes

  • "The book was written with Hemingway." → "The book was written by Hemingway." · Hemingway is the author (the agent), not a tool.
  • "I cut the paper by scissors." → "I cut the paper with scissors." · Scissors are the tool in your hand, so use with.
  • "I'll go to the airport with bus." → "I'll go to the airport by bus." · Mode of transport takes by, with no article.
  • "She came at the meeting by her boss." → "She came to the meeting with her boss." · A companion takes with, not by.
  • "We talked with phone for an hour." → "We talked by phone for an hour." (or "on the phone") · Channel of communication takes by.

One nice trick: when by is followed by a method of transport, English usually drops the article. We say "by car," "by bus," "by plane" — no "a" or "the." But the moment you switch to in/on (see our transport article), the article comes back: "in the car," "on the bus."

Exam Trap

Reading and listening sections love sentences that pile by and with into the same line so test-takers blur them. Example pattern: "The report was prepared by the marketing team with input from external consultants." A comprehension question may then ask who prepared the report and who contributed. If you don't separate by (the doer) from with (the helper or instrument), you'll mix them up. TOEIC Part 5 and Part 6 also hide this in passive constructions: a sentence like "The proposal was reviewed ___ a panel of experts" must be by because "a panel of experts" is the agent, not a tool. Slow down, ask "who did it?" versus "what was used?", and the answer falls out.

Mini Practice

  1. The email was sent _____ the project manager last night.
  2. She fixed the chair _____ a screwdriver and some glue.
  3. We can confirm the booking _____ email or phone.
  4. He traveled across the country _____ his best friend.
  5. Most students get to campus _____ bike.

Answer Key

  1. by — The project manager is the agent of the passive verb was sent.
  2. with — A screwdriver and glue are tools.
  3. by — Email and phone are channels of communication, so use by.
  4. with — A companion takes with.
  5. by — Mode of transport takes by, no article.

Tiny Summary

  • By = who did it (agent) or how it was done at a method level (by train, by email, by card).
  • With = what tool was used (with a knife) or who came along (with a friend).
  • Pay by card vs pay with a card are both fine; by leans formal, with leans concrete.
  • Always drop the article after by for transport ("by bus" not "by the bus").

Two questions to ask before you choose: Who is doing it? and What are they using? Answer those, and by versus with stops being a guessing game.