Pre-Money & Post-Money Valuation Tool
Enter any two values to compute the third. You can also use investment + target ownership to back into valuation.
What are pre-money and post-money valuations?
Pre-money valuation is what your startup is worth immediately before a new investment. Post-money valuation is what it is worth immediately after the investment is added.
The relationship is simple:
- Post-money = Pre-money + Investment
- Investor ownership = Investment / Post-money
Even though the equations are straightforward, founders often make mistakes when negotiating dilution, option pools, or target ownership. A calculator helps you see the impact quickly and avoid surprises.
Why this matters for founders and investors
For founders
- Understand how much equity you give up for a specific check size.
- Model multiple raise scenarios before term sheet discussions.
- Set realistic expectations for current and future dilution.
For investors
- Verify ownership outcomes based on invested capital.
- Compare opportunities with consistent valuation math.
- Estimate share count outcomes when fully diluted shares are known.
How to use this calculator
Most common workflow
Enter pre-money valuation and investment amount. The tool computes:
- Post-money valuation
- Investor ownership percentage
- Founder/previous shareholder remaining ownership
Reverse workflow
If you know the desired ownership target (for example 20%) and the check size, enter:
- Investment amount
- Target ownership percentage
The calculator backs into implied post-money and pre-money valuations.
Example scenarios
Example 1: Classic seed round
Pre-money = $8,000,000 and investment = $2,000,000.
- Post-money = $10,000,000
- Investor ownership = 20%
- Existing shareholders = 80%
Example 2: You know post-money and check size
Post-money = $12,000,000 and investment = $3,000,000.
- Pre-money = $9,000,000
- Investor ownership = 25%
Example 3: Ownership-first negotiation
You want to raise $1,500,000 and offer 15% ownership.
- Implied post-money = $10,000,000
- Implied pre-money = $8,500,000
Common mistakes to avoid
- Mixing up pre and post: this causes incorrect dilution calculations.
- Ignoring option pool changes: option pool expansion can increase founder dilution.
- Using inconsistent numbers: pre + investment must equal post.
- Forgetting fully diluted basis: always clarify whether percentages are fully diluted.
Practical fundraising tips
Model several rounds, not just one
A “good” valuation today can still lead to heavy dilution later. Build a multi-round view (seed, Series A, Series B) to understand long-term ownership.
Pair valuation with milestones
Valuation is easier to defend when linked to traction milestones: revenue growth, user retention, gross margin, and pipeline quality.
Use clean cap table assumptions
If you know fully diluted shares, this calculator can estimate share price and new shares issued. Keep these assumptions documented during negotiations.
Quick FAQ
Is a higher pre-money always better?
Not always. A valuation should be realistic relative to stage, traction, and market conditions. Overpricing can make future rounds harder.
What if my inputs conflict?
If pre-money, post-money, and investment do not satisfy the core equation, the calculator flags the mismatch so you can correct values.
Can this replace legal or financial advice?
No. This is a decision-support tool for planning and education. Final deal terms should be reviewed with legal and finance professionals.