Startup valuation arithmetic.

Pre-money/post-money valuation calculator computes the core arithmetic of every venture capital deal. Pre-money valuation = company value before investment. Post-money valuation = pre-money + investment. Investor ownership % = investment / post-money. Founder dilution = same as investor ownership.

Example: founders raise 2M at 10M post-money valuation. Pre-money = 8M. Investor gets 2M / 10M = 20% ownership. Founders diluted from 100% to 80%. If founders held 1M shares pre-round, price per share = 8M / 1M = 8. Investor receives 250,000 new shares (2M / 8).

Watch for valuation games: 'we raised at 10M valuation' could mean either pre or post. Pre-money is the headline founders prefer (sounds bigger). Post-money is what investors track. Always clarify which. Down rounds (post-money lower than previous post-money) trigger anti-dilution provisions, often punishing founders heavily through ratchet adjustments.

Run it with sensible defaults

Using investment amount of 2,000,000, post-money valuation of 10,000,000, founder shares pre-round of 1,000,000, the calculation works out to 8,000,000.00. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Investment Amount, Post-Money Valuation, and Founder Shares Pre-Round — do not pull with equal force. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

How the math works

Pre-money = post-money - investment. Investor % = investment / post-money. Price per share = pre-money / founder shares pre-round. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

Why investors run this

Most people's intuition for compounding is wrong — not because the math is hard, but because linear thinking doesn't account for curves. Running numbers through a calculator like this one is the cheapest way to recalibrate that intuition before making an irreversible decision about contribution rate, asset mix, or retirement age.

What this doesn't capture

Steady-rate math ignores real-world volatility. Actual returns are lumpy; sequence-of-returns risk matters most in drawdown; fees and taxes drag on compound growth; and behaviour changes in drawdowns can reduce outcomes below the projection. Treat the number as one scenario, not a forecast.