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YC SAFE & Valuation Calculator
Model how the YC $125K + $375K MFN SAFE converts, and what a new post-money SAFE does to your ownership.
YC SAFE
Implied post-money cap: $1,785,714
New SAFE
New investor ownership: 10.00%
Ownership after conversion
The MFN note has no cap, so its ownership depends on the next priced round's terms. It will match any better terms offered before that round.
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Next step
Now understand the paperwork behind the numbers
The calculator shows dilution; the SAFE guide explains the valuation cap, discount, MFN and pro-rata clauses you’ll actually sign.
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How to use this tool
Step 1
Enter the YC terms
$125K for 7% is the standard starting point.
Step 2
Add a new SAFE
Enter the investment amount and post-money cap.
Step 3
Read the ownership
See founder, YC, and new investor ownership after conversion.
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Index
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FAQ
What is a post-money SAFE?
A Simple Agreement for Future Equity that converts into shares after the next priced round, based on the company's valuation immediately after that round (post-money).
How does the YC $500K deal work?
YC invests $125K on a post-money SAFE for 7% ownership, plus a $375K MFN SAFE that has no cap but gets the same terms as the most favorable future SAFE.
Is this legal advice?
No. This is a simplified model for planning. Always have a lawyer review your actual SAFE documents.
Is this SAFE calculator free?
Yes. All the dilution math runs in your browser, with no signup and no data stored.
Does it model the YC standard deal?
Yes — $125K for 7% on a post-money SAFE plus the $375K uncapped MFN SAFE, so you can see the combined dilution at your next priced round.
Is this legal or financial advice?
No. It's an estimate to help you understand the mechanics. Have a startup lawyer review any SAFE before signing.
Keep reading
Deep dive
The YC SAFE, Explained →
Post-money SAFE mechanics, cap tables, and what founders actually sign.
Fundraising
Post-Money SAFE Explained →
Cap math, dilution tables, MFN clauses and the four standard forms.
Deep dive
The $500K YC Deal →
How the standard $125K + $375K SAFE actually works.
Playbook
YC Equity Split for Co-Founders →
Why YC pushes 50/50 splits, when to deviate, and vesting basics.
New here? Start on the YCInsight homepage — every YC database, founder story and Q&A in one place. Or jump straight to the free YC databases.