A discount on a or convertible note is a percentage reduction off the price-per-share at the next priced round. The discount is the early investor's reward for putting cash in before the round was priced. Together with the , it's one of the two standard mechanisms for converting an unpriced early check into shares.
Say an investor wires $200K on a SAFE with a 20% discount. Eighteen months later, the company prices a Series Seed at $2.00 per share. The discount lets the SAFE-holder buy in at 80% of that price, or $1.60 per share. Their $200K converts into 125,000 shares ($200K / $1.60), versus 100,000 shares ($200K / $2.00) for an investor who joined fresh at the priced round.
The market-standard SAFE discount is between 10% and 25%, with 20% the most common pre-seed default. Discounts below 10% rarely show up in modern SAFEs because the YC post-money template normalized the higher numbers; discounts above 25% are unusual and start to look more like pre-money cap territory.
Most SAFEs include both a discount and a cap. At conversion, the SAFE-holder gets the better of the two outcomes: the cap-adjusted price or the discounted round price. If the round prices well above the cap, the cap binds and the discount doesn't matter. If the round prices near or below the cap, the discount usually delivers the better number. From the founder's perspective, every SAFE with both terms is essentially a "lower-of" instrument that costs more dilution than either term in isolation.
Stacked SAFEs at different discount levels (one with 10%, another with 20%) all convert at the priced round at once. Each tier dilutes the founders separately, and the math gets non-obvious quickly. Any time you sign a new SAFE (whether to a friend, an angel, or an accelerator), model the cap table at the next priced round including all current SAFEs at their actual cap and discount terms.