Startup Post-Money Valuation Calculator
Use this tool to estimate post-money valuation, investor ownership, and dilution after a fundraising round.
What is post-money valuation?
Post-money valuation is the value of a company immediately after a new investment is made. It is one of the most important startup finance numbers because it directly determines ownership percentages, dilution, and implied value for founders and investors.
In simple terms, post-money tells you what the whole pie is worth after cash comes in. Once you know the size of that pie, you can calculate how big each slice is for existing shareholders and new investors.
The core formula
The most common formula is:
- Post-money valuation = Pre-money valuation + New investment
- Investor ownership % = New investment / Post-money valuation
Example: If pre-money is $8M and an investor puts in $2M, the post-money is $10M. The investor owns 20% ($2M / $10M), and previous shareholders own 80% collectively.
How this calculator helps founders
1) See dilution before signing a term sheet
Dilution is not automatically bad. Taking capital can increase total company value dramatically. But dilution should be intentional. A quick calculation helps you understand whether a round gives away too much for too little.
2) Run scenario planning
You can test multiple round sizes and valuation assumptions in minutes. This lets you compare options such as:
- Raise less now and preserve ownership
- Raise more now to extend runway
- Accept a lower valuation with strategic investor value-add
3) Translate valuation into cap table mechanics
If you include shares outstanding, you can estimate implied price per share and number of shares to issue. This is useful for board conversations, internal planning, and communicating with counsel before legal docs are drafted.
Reverse calculation: investment needed for target ownership
Many founders negotiate toward a target dilution number, such as 15% or 20%. The reverse formula estimates how much capital corresponds to that ownership target at a given pre-money valuation:
- Required investment = (Pre-money × Target ownership) / (1 − Target ownership)
If pre-money is $6M and investor target ownership is 25%, required investment is $2M. Post-money would be $8M. This gives both sides a straightforward way to align terms.
Common mistakes in valuation math
- Mixing pre and post-money numbers during negotiation and accidentally overstating ownership.
- Ignoring option pool changes, which can create additional dilution.
- Confusing ownership with control; governance rights also matter.
- Focusing only on headline valuation instead of liquidation preferences and other terms.
Beyond the formula: what sophisticated investors review
Burn multiple and runway
A round that looks attractive on valuation can still be risky if burn is too high. Investors care about how efficiently capital turns into growth and milestones.
Milestone-based value creation
Strong founders connect round size to specific milestones: product launch, revenue targets, retention thresholds, or regulatory progress. This improves future fundraising leverage.
Long-term ownership strategy
Founders should model not just this round, but the next two rounds as well. Preserving enough ownership for the team can be crucial for motivation and strategic flexibility.
Quick practical workflow
- Enter your pre-money valuation estimate.
- Enter proposed investment amount.
- Optional: add current shares outstanding for per-share estimates.
- Optional: add target ownership % to see reverse sizing guidance.
- Compare scenarios and discuss terms with legal and finance advisors.
Final thought
A post-money calculator does not replace legal advice or a full cap table model, but it gives founders a clear first-pass framework for negotiation. When you understand how valuation, ownership, and dilution interact, you make better financing decisions with far fewer surprises.