Worksheet
Ownership Percentage Calculator
What this is: A step-by-step worksheet for calculating exactly how much of your company you're giving away in an equity deal, before you sign anything. Steps 1 through 4 walk through the formula by hand with a worked example; Step 5 is a live calculator that does the same math instantly with your own numbers.
Step 1: Work Out the Pre-Money Valuation
Pre-Money Valuation = what the business is worth before the new money comes in.
Pre-Money Valuation = ______________________
Worked example (MANIAC MINDZ): ₦20,000,000
Step 2: Add the Investment
Post-Money Valuation = Pre-Money Valuation + Investment Amount
| Amount | |
|---|---|
| Pre-Money Valuation | ₦20,000,000 |
| + Investment Amount | ₦5,000,000 |
| = Post-Money Valuation | ₦25,000,000 |
Step 3: Calculate the Investor's Percentage
Investor % = Investment Amount ÷ Post-Money Valuation × 100
| Amount | |
|---|---|
| Investment Amount | ₦5,000,000 |
| ÷ Post-Money Valuation | ₦25,000,000 |
| = Investor % | 20% |
Notice this used the post-money valuation, not the pre-money valuation. This is the single most common calculation mistake founders make, see Common Mistakes.
Step 4: Calculate the Founder's Remaining Percentage
Founder % = 100% − Investor %
100% − 20% = 80%
Step 5: Calculate It Live
Type your own numbers in, the post-money valuation and both percentages update as you type, using exactly the formulas from Steps 1 through 4 above.
Step 6: Dilution Check (If This Isn't the First Investor)
If you already gave away shares before, your remaining percentage, not 100%, is what gets diluted.
Your New % = Your Old % × (Pre-Money Valuation ÷ Post-Money Valuation)
Worked example: Mr A already gave 20% to Mr B last year. He now has 80%. A new investor, Mr C, joins on terms where Mr C receives 15%.
Mr A's New % = 80% × (85% remaining pool ÷ 100%) = 68% Mr B's New % = 20% × 85% = 17% Mr C's New % = 15% Total = 68% + 17% + 15% = 100%
Run your own dilution numbers here:
Once you finish this worksheet, transfer the final numbers into your Cap Table Template.