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Convertible Note Calculator

A convertible note through to conversion, with the accrued interest converting alongside the principal. Unlike a SAFE, a note is debt: it accrues interest, it has a maturity date, and both of those are real terms rather than formalities.

Also called: convertible debt calculator, note conversion calculator.

$
%
$
%
$
Interest basis
Amount converting
$5,600,000.00

$5,600,000.00 converts, being 5,000,000 of principal plus $600,000.00 of interest, into 1,400,000 shares at $4.00. 600000 of interest accrued at 8% simple over 1.5 years, and it converts rather than being repaid. It buys 150000 of the shares issued. The cap governed at 4 a share against 6.4 after the discount.

Interest accrued
$600,000.00
Shares issued
1,400,000
Conversion price a share
$4.00
Stake on conversion
12.28%
Price at the cap
$4.00
Price after the discount
$6.40
On the interest
600000 of interest accrued at 8% simple over 1.5 years, and it converts rather than being repaid. It buys 150000 of the shares issued.
Which term applied
The cap governed at 4 a share against 6.4 after the discount.

An estimate, not an offer or a guarantee. Projected returns assume the rate you entered holds for the whole term, which no market does.

Method and background

How this is calculated

The note accrues interest, usually simple rather than compound, and at conversion the entire balance including that interest buys shares at the lower of the cap price and the discounted round price. The interest is therefore not repaid, it is converted, which makes an eight percent rate over eighteen months worth about twelve percent more equity to the investor. The maturity date is the other difference from a SAFE: if no qualifying round happens before it, the note becomes repayable, and a startup that cannot repay is negotiating from a weak position. That is the risk a SAFE was invented to remove.

the note accrues interest and the whole balance converts, so the interest buys equity rather than being repaid
P
Principal
r
Interest rate
t
Years

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

a note converting after eighteen months

Principal
$5,000,000.00
Interest rate
8%
Years to conversion
1.5
Valuation cap
$40,000,000.00
Discount
20%
Pre-money valuation of the round
$80,000,000.00
Shares outstanding before
10,000,000
Interest basis
Simple

Amount converting$5,600,000.00

5m x 8% x 1.5, converting at the 4 cap price

Open this example

compounding adds a little more

Principal
$5,000,000.00
Interest rate
8%
Years to conversion
1.5
Valuation cap
$40,000,000.00
Discount
20%
Pre-money valuation of the round
$80,000,000.00
Shares outstanding before
10,000,000
Interest basis
Compounded annually

Amount converting$5,611,844.62

boundary: 1.08^1.5 against 1 + 0.08 x 1.5

Open this example

Method and limits

What it assumes

  • A qualifying priced round occurs before maturity.

What it deliberately does not model

  • Maturity, repayment and change of control terms often matter more than the conversion arithmetic.
  • Interest treatment varies between notes and some accrue only until a stated date.

Formula version 1.0.0 · definition 1.0.0 · United States · Report a problem with this calculator

Frequently asked questions

Is the interest paid back in cash?
Usually not. It converts into equity along with the principal, so the rate buys the investor more shares rather than producing a cash return.
How does a note differ from a SAFE?
A note is debt with interest and a maturity date. If no qualifying round happens before maturity it becomes repayable, which is a real risk a SAFE does not carry.