SAFE & Convertible Note Calculator

Simulate YC Post-Money SAFE conversions, valuation cap mechanics, and founder dilution in priced Series A equity rounds.

SAFE & Convertible Note Cap Table Calculator

Simulate Y Combinator Post-Money SAFE, Pre-Money SAFE, and valuation cap conversions into Series A priced equity.

1. SAFE Instrument Terms

2. Converting Series A Priced Round

Post-Series A Ownership Breakdown

Founders & Common Stock:73.47%
SAFE Investor Conversion:8.16%
Series A New Investors:18.37%

Cap Table Conversion Metrics

Effective SAFE Price Per Share:$0.5625
SAFE Shares Issued:888,889
Series A Shares Issued:2,000,000
Post-Series A Company Valuation:$15,000,000

How Startup SAFE Conversions Work

For tech startups and venture-backed founders, SAFEs offer unmatched speed and low legal overhead when closing angel and seed rounds. However, failing to model how multiple notes convert can lead to severe and unexpected founder dilution upon closing a Series A.

YC Post-Money SAFE Ownership Formula

Target Ownership % = SAFE Investment Amount ÷ Post-Money Valuation Cap

Venture Fundraising Scenarios

  • Pre-Seed & Seed Fundraising Strategy

    Understand exactly how much of your startup you are giving away before signing YC Post-Money SAFE agreements with angel investors.

  • Multiple SAFE Stacking Dilution Analysis

    Simulate the compounding dilution effect of raising multiple rolling SAFE notes at different valuation caps.

  • Series A Term Sheet Negotiations

    Forecast how existing convertible instruments will convert into preferred stock alongside new lead institutional venture capital checks.

  • Founder Cap Table Ownership Protection

    Ensure founders maintain controlling voting equity and adequate employee option pool buffers through subsequent funding rounds.

Key Calculator Features

Post-Money vs Pre-Money SAFE Logic

Implements the official Y Combinator Post-Money SAFE formula as well as legacy pre-money convertible debt conversion mechanics.

Cap vs Discount Price Comparison

Automatically determines whether the valuation cap or the discount rate yields the more favorable conversion share price for investors.

Visual Post-Round Ownership Bar

Instant visual breakdown of founder common stock, early SAFE noteholders, and new Series A lead venture investors.

Complete Client-Side Confidentiality

Model sensitive cap table shares and confidential pre-money valuations 100% locally with zero server transmission.

Frequently Asked Questions

What is a SAFE (Simple Agreement for Future Equity)?

A SAFE is a financing instrument created by Y Combinator in 2013 to streamline early-stage startup fundraising. It allows investors to inject capital today in exchange for the contractual right to receive equity in a future priced round (such as a Series A) at a pre-agreed valuation cap or discount.

What is the difference between a Pre-Money and Post-Money SAFE?

In a Pre-Money SAFE, the investor's ownership is calculated against the company's valuation before the investment, meaning each subsequent SAFE dilutes earlier SAFEs. In a Post-Money SAFE (the current YC standard), the investor's ownership percentage is fixed immediately (Investment ÷ Valuation Cap) and only founders/common shareholders absorb the dilution until the priced round.

How does a Valuation Cap work?

A Valuation Cap sets a maximum ceiling valuation at which the SAFE converts into equity. If the Series A valuation exceeds the cap, the SAFE investor converts at the lower cap price, receiving more shares per dollar than new Series A investors as a reward for taking early risk.

What happens if a priced round never occurs?

If a priced equity round does not occur before a liquidity event (like an acquisition or IPO), SAFEs typically convert at the valuation cap or are repaid the original investment amount prior to common stockholders receiving proceeds.

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