IndexTool
The dilution modeler. Pre-seed to A, in plain English.
Plug in your rounds. See exactly what each one costs you, why, and what you walk into Series B owning. Every number is annotated, the math is shown, and the URL is the save file — copy it, share it, send it to your co-founder.
Preset
The rounds
Stage 1
Pre-money
$8.5M
New investor stake
15.0%
Stage 2
Pre-money
$21.0M
New investor stake
16.0%
Stage 3
Pre-money
$48.0M
New investor stake
20.0%
Glossary, in plain English
- Pre-money
- What investors agree the company is worth before their cash arrives. Post-money − raise.
- Post-money
- Pre-money plus the new round. The denominator for the new investor's stake.
- ESOP top-up
- Refreshing the option pool to a target % of the post-close cap, almost always carved pre-money. Founders absorb the dilution.
- Carved pre-money
- The pool sits inside the pre-money valuation. Translation: it costs founders, not new investors.
- Dilution
- Your % shrinks because new shares were issued. The company can be worth more even as your slice gets thinner.
The waterfall
Founders own at exit of Series A
46.7%
Total raised
$17.5M
Final post-money
$60M
Per-founder paper
$14.0M
2 founders, equal split
01After Pre-seed
$1.5M @ $10M post
Founders
76.5%
ESOP
8.5%
Investors
15.0%
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Pre-money
$8.5M = $10M − $1.5M
New investor stake
15.00% = $1.5M ÷ $10M
ESOP top-up (pre-money)
+10.00pp to reach 10%
Founder cost this round
−23.50pp (23.5% of prior stake)
02After Seed
$4M @ $25M post
Founders
61.8%
ESOP
10.1%
Investors
28.1%
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Pre-money
$21.0M = $25M − $4M
New investor stake
16.00% = $4M ÷ $25M
ESOP top-up (pre-money)
+3.50pp to reach 12%
Founder cost this round
−14.70pp (19.2% of prior stake)
03After Series A
$12M @ $60M post
Founders
46.7%
ESOP
12.0%
Investors
41.3%
Show the mathHide the math
Pre-money
$48.0M = $60M − $12M
New investor stake
20.00% = $12M ÷ $60M
ESOP top-up (pre-money)
+4.92pp to reach 15%
Founder cost this round
−15.07pp (24.4% of prior stake)
Investor read
Standard outcome.
This is roughly the median founder ownership at Series A in the public datasets. Not a problem on its own, but every subsequent round is now expensive in absolute terms — push pre-money valuation harder than ESOP %.
- Total dilutionFounders went from 100% to 46.7% — a 53.3pp drop over 3 rounds.
- Costliest roundPre-seed took 23.5pp off the founders (23.5% of prior stake), driven by a 10.0pp ESOP top-up plus the 15.0% new-investor stake.
- Paper valueAt $60M post-money, each of 2 founders is holding ~$14.0M of paper. Liquidation preferences and option vesting will move this in real life.
- ESOP at exitPool sits at 12.0%. Anything below 10% going into B usually triggers another top-up; anything above 18% is harder to defend without a hiring plan to back it.
Assumptions: ESOP top-up is carved pre-money, so existing holders absorb the dilution. SAFEs and convertible notes aren't modeled — assume they've already converted into the priced round above. Per-founder paper value is shown at final post-money and assumes equal split; real splits and liquidation preferences will move the answer.
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