startzero.money

Seed funding calculator

How much to raise for the runway you need, and how much of your company the round costs.

Your numbers

$

After raising

$

Today

%

Each month

$

Already in the bank

%

For surprises

$

After the round

Amount to raise
$695.2K
$579.3K for 18 months, plus a 20% buffer
Share you sell
13.9%
at $5.0M after the round
Monthly burn today
$35,000
costs minus revenue
The money lasts
22 months
Revenue covers costs from month 44

Cash in the bank after the raise

−$100.0K$0$100.0K$200.0K$300.0K$400.0K$500.0K$600.0K$700.0KM1M4M7M10M13M16M19M2218-month targetRuns out
How it’s calculated
  • monthly burn = monthly costs − monthly revenue; revenue grows by your growth rate each month
  • cash needed = the lowest point your cash reaches over the months you chose, starting from zero
  • amount to raise = cash needed × (1 + buffer) − cash you already have
  • share you sell = amount to raise ÷ valuation after the round (post-money)

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Guides that use this calculator

Questions

How many months of runway should a seed round buy?

Many founders aim for 18 to 24 months, because the next raise usually takes longer than planned. Carta’s data shows a median of about two years between a seed round and a Series A.

What valuation should I use?

The post-money valuation you expect: the valuation cap on your SAFE, or the agreed pre-money valuation plus the new money. If you don’t know yet, try a few values and watch how the share you sell changes.

How much of my company should I sell at seed?

Many seed rounds sell between 15% and 25%. Selling much more early leaves less room for later rounds and an employee option pool, so raise for a clear milestone rather than the biggest amount on offer.