SAFE & Convertible Note Conversion Calculator

Raising on SAFEs? See what they cost you at conversion, before the term sheet makes it real. Enter each instrument’s cap and discount, add your round terms, and get the conversion price, shares issued and ownership per instrument — plus total founder dilution. Notes accrue interest day-for-day (ACT/365); every instrument converts at the lower of its cap price and its discount price.

Round pre-money valuation

New money raised in the round

Pre-round fully-diluted shares

Founder shares (of the above)

Conversion date (notes accrue interest to it)

Converting instruments

SAFE 1

Instrument

Investment amount

SAFE type

Valuation cap (blank = none)

Discount % (blank = none)

MFN — no cap, no discount; inherits the best terms of the other SAFEs in this scenario

Output

Conversion preview

No value yet

Planning estimate — not financial or legal advice.

How this is calculated

Round price per share: Pre-money valuation ÷ pre-round fully-diluted shares (outstanding shares plus the reserved option pool, excluding the converting instruments).
Conversion price — the lower-of rule: Each instrument converts at the LOWER of its cap price and its discount price. Discount price = round price × (1 − discount %). An instrument with neither converts at the round price.
Post-money SAFE cap price: Post-money cap ÷ company capitalization immediately before the priced round, including all converting SAFEs and the option pool but excluding new-money shares. With t = Σ(investment ÷ cap) over capped post-money SAFEs, cap price = cap × (1 − t) ÷ pre-round fully-diluted shares.
Pre-money SAFE cap price: Pre-money cap ÷ pre-money fully-diluted capitalization, excluding converting instruments.
Convertible note interest (ACT/365): Simple: principal × rate × days ÷ 365. Compound (annual): principal × ((1 + rate)^(days ÷ 365) − 1). Principal plus accrued interest converts at the same lower-of rule. Example: $300,000 at 8% for 367 days accrues $24,131.51.
MFN (most favored nation): An uncapped, undiscounted MFN SAFE takes the lowest conversion price of the other SAFEs converting in the same scenario, if lower than the round price; with none, it converts at the round price.
Shares and dilution: Shares issued = floor(converting amount ÷ conversion price). Ownership = shares ÷ post-round fully-diluted shares. Founder dilution = founder % before the round − founder % after conversions and new money.

Planning estimate — not financial or legal advice.