Post-money valuation is what your company is worth right after new investment comes in. It equals the pre-money valuation plus the money raised.
Formula
Post-money valuation = pre-money valuation + investment
Example
You raise $500K on a post-money SAFE with a $5M cap. That investor is set to own $500K ÷ $5M = 10% when the SAFE converts, before any later round dilutes them.
Why it matters for early-stage founders
Post-money SAFEs, now the most common pre-seed instrument, are priced on the post-money cap. Each SAFE you add dilutes founders, not earlier SAFE holders, so the number adds up faster than many founders expect.
The common mistake
Adding SAFEs without tracking the total. Three post-money SAFEs at 7% each already mean founders give up over 20% before the first priced round.
Model how each round dilutes you
Run your SAFEs and priced round through the dilution calculator to see what founders own at the end.
Try the dilution calculator