Updated April 20, 2026 · Startup & VC · Educational use only ·

SAFE Note Calculator

SAFE note conversion math.

Calculate SAFE note conversion ownership and return based on valuation cap, discount rate, and the round's pre-money valuation.

What this tool does

This calculator models how a SAFE note converts to equity when a qualified funding round occurs. It compares two conversion prices—one based on the valuation cap and one based on the discount percentage—and applies the more favorable to the investor. The result shows your ownership percentage post-conversion and the return multiple on your initial investment relative to the qualified round valuation. The conversion price is the primary driver of ownership; changes to the valuation cap or discount percentage directly shift this calculation. A typical scenario involves an early investor holding a SAFE who sees their instrument convert during a Series A or later round. Note that this calculation assumes conversion occurs and doesn't account for subsequent dilution, employee option pools, or other securities that may affect final ownership stakes. Results are for illustrative purposes only.

Enter Values

Currency($)

Investment Amount($)

Valuation Cap($)

Discount %

Qualified Round Valuation($)

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Formula Used

O = I / min (C, V (1 - d)) \times 100

I

Investment

C

Cap

V

Round

d

Discount (entered as a percentage value)

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Calculations or display — let us know.

Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

SAFE (Simple Agreement for Future Equity) is a startup investment instrument that converts to equity at the next priced round. Two key terms: valuation cap (max valuation for conversion) and discount (% off the round price). Investor gets the better of the two. Common structure pioneered by Y Combinator.

100,000 SAFE with 5M cap and 20% discount. Series A round at 8M valuation. Cap conversion: 100k / 5M = 2.0% ownership. Discount conversion: 100k / (8M × 80%) = 100k / 6.4M = 1.56%. Investor takes better deal: 2.0% via cap. Series A shares worth 160k. Return multiple: 1.6x at conversion. Future upside if startup continues growing.

SAFE benefits: simpler than convertible notes (no interest, no maturity), founder-friendly (no debt, faster closing), VC-friendly (clear conversion mechanics). Drawbacks: investor takes risk if no priced round happens (SAFEs sit indefinitely). Most startups raise priced round within 18-24 months of SAFE - those that don't often fail.

Run it with sensible defaults

Using investment amount of 100,000, valuation cap of 5,000,000, discount of 20%, qualified round valuation of 8,000,000, the calculation works out to 2.00%. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Investment Amount, Valuation Cap, Discount %, and Qualified Round Valuation — do not pull with equal force. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

How the math works

Cap price = investment / cap. Discount price = investment / (round × (1 - discount)). Use lower (better for investor). Ownership = investment / conversion val × 100.

Using this well

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. The number represents one scenario rather than a forecast.

Example Scenario

££100,000 SAFE with ££5,000,000 cap, 20% discount, round ££8,000,000 = 2.00%.

Inputs

Investment Amount:£100,000

Valuation Cap:£5,000,000

Discount %:20

Qualified Round Valuation:£8,000,000

Expected Result2.00%

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

This calculator computes SAFE note conversion ownership by determining the effective conversion price and applying it to the investment amount. The conversion price is the lower of two prices: the valuation cap divided into the investment, or the qualified round valuation reduced by the discount percentage, then divided into the investment. The model assumes the investor converts at whichever price is more favourable. Ownership percentage is then calculated by dividing the investment amount by this conversion price and multiplying by 100. The calculator does not model dilution from future funding rounds, the timing of conversion, tax treatment, or fees associated with the instrument.

References

Y Combinator - SAFE Documents

Frequently Asked Questions

Cap vs discount - which matters more?

Both. Cap protects against high-valuation round (you don't get diluted from huge round). Discount protects against low-valuation round (you get bonus shares). Most SAFEs include both. Cap usually more impactful when company grows fast.

Pre-money vs post-money SAFE?

Older 'pre-money SAFE': dilution comes after conversion. Current 'post-money SAFE' (2018+): your % is locked at conversion. Post-money simpler for everyone, more common today. Same investment, same cap can produce different ownership depending on which type - check carefully.

What if no priced round?

SAFE sits indefinitely. Some convert at: M&A exit, IPO, dissolution. Most startups raise within 18-24 months or fail. SAFEs in startups that fail without conversion typically worth zero. Risk is real - SAFE investors should expect 50%+ failure rate.

Convertible note vs SAFE?

Convertible note: debt with interest + maturity date, more complex, must convert or repay. SAFE: not debt, simpler, can sit indefinitely. SAFE much more common in 2020+ for early stage. Convertible notes still used for bridge rounds and complex situations.

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