How much money do you need to start day trading?
It depends on what you trade and how you trade it. Here's the honest picture for the most common routes.
Stocks
In the US, frequent day trading of stocks in a margin account has historically required a $25,000 minimum under FINRA's pattern day trader rule. Below that, you're limited in how many day trades you can make. Check the current rule with your broker; it has been under review. Cash accounts avoid the rule but come with settlement limits.
Futures
Futures aren't subject to the pattern day trader rule, and micro contracts make small accounts workable. A Micro E-mini Nasdaq-100 (MNQ) moves $2 per point, so a 20-point stop risks $40 per contract. Brokers set the margin you need per contract, and it varies, so check yours. The catch: a small account can only take a few losses before it's gone, so risk per trade has to be small (lesson 5).
Prop firm evaluations
Instead of risking your own capital, you can pay a fee to trade a firm's account under its rules. The median list price of a 50K futures evaluation at the firms we track is $170. Most people don't pass on the first try, so budget for several attempts. Lesson 10 and our prop firm vs your own money guide cover this in detail.
Can you start with $100?
You can open some accounts with very little, but $100 leaves no room to survive the normal losing streaks every trader has, and fees take a bigger bite of a small account. What costs nothing is practice: simulated trading and market replay (lesson 7) let you learn the mechanics and test a plan before any money is at risk.
The rule that matters most
Only trade money you can afford to lose completely. Whatever the amount, what decides whether it lasts is how much of it you risk on each trade, not how big it is.