Arrow Lab

Organic chemistry mechanisms, one curved arrow at a time Stuck on a mechanism? Snap it. Then draw it, every arrow checked.

Photograph a reaction from your Orgo 1, Orgo 2 or MCAT homework. Arrow Lab builds its mechanism and you draw every curved arrow, with feedback on each move.

Scan your homework freeor try a mechanism now →

1 free scan, no sign-up. Then Scan Standard · cancel anytime, full refund · Plans & pricing

SN2 · Step 1 ✓ Backside attack, bromide leaves

How it works

  1. Snap

    Take a photo of one reaction from your homework, notes or textbook.

  2. Confirm

    Arrow Lab shows what it read. Fix anything before the mechanism is built.

  3. Draw

    Draw each step yourself. Every arrow is checked, with a hint when you get stuck.

Most popular

Scan Standard

For the problem set due this week, and the one after.

  • Snap any reaction from your homework and draw its mechanism, every arrow checked
  • 40 scan credits a month, about 36 problems
  • The whole practice library for Orgo 1 and Orgo 2
  • A scan that fails uses no credits

$15 / month

Scan Standard

Cancel anytime - full refund

Not sure yet? Scan 1 problem free, no sign-up.

Practice every mechanism free

3-day money-back guarantee on your first payment (14 days in the EU and UK). Cancel anytime.

Compare plans. Secure checkout by Stripe, no account needed to pay.

Or keep the 30 greatest hits for $5, one payment.

Or start free

The whole practice library, free

5,349 problems, every arrow checked. Free with an account, no card.

Every mechanism and practice question in Orgo 1 and Orgo 2, with feedback on each arrow, worked solutions, quiz mode and search. Free with an account, no card.

Practice every mechanism free

Try the 4-minute demo → Draw a real mechanism in your browser. No account needed. Scan a reaction free → Snap a reaction and practice it arrow by arrow. 1 free scan now, no sign-up; 1 more with a free account. Open the mechanism editor → Draw any mechanism yourself, arrow by arrow. Read the free Orgo 1 study guide → One printable guide, open to everyone. No email needed to read it.

Reaction mechanisms, step by step

Browse 5349 free practice problems with worked solutions →

Learn IUPAC naming: rules with worked examples for every functional group

Show all 29 mechanisms

All reaction mechanisms · All topics

Questions before you pay

What is a scan credit?

A credit is the unit a scan is metered in: a typical mechanism uses about 1, a long or tricky one 2–4, and you see the estimate before you build.

What if the scan reads my problem wrong?

You check what Arrow Lab read before anything is built, and you can correct it. A scan that fails uses no credits.

Can I cancel or get a refund?

Yes. Cancel anytime from Manage subscription in your account and you won’t be charged again. Email us within 3 days of your first payment (14 days in the EU and UK) and we refund it in full, no questions asked. Read the full refund policy · See pricing

Does it work in Spanish and Portuguese?

Yes. Arrow Lab works in English, Spanish and Brazilian Portuguese: pick your language in the menu or at the bottom of any page. You can scan homework written in Spanish or Portuguese too.

Who answers if I get stuck?

A small team, not a big company: a real person reads every email and usually replies within two business days. Write to support@arrowlabchem.com, send a suggestion or request a feature.

Stuck on a mechanism? Snap it.

Your first scan is free: no sign-up, no card. Good luck with orgo. You’ve got this.

Scan your homework freeor try a mechanism now →

Then Scan Standard for $15/month · cancel anytime, full refund