← Back to articles

Interest Rate on Convertible Notes: Impact on Eventual Equity

What Is Convertible Note Interest?

Convertible note interest is a small percentage yield that accrues over time until the note converts or the company repays it. Unlike bonds where interest is paid in cash, convertible note interest is typically added to the principal and converted into equity along with the original investment.

Standard interest rates range from 0-8%, with 2-5% being market typical. The interest is not profit-taking—it's compensation for the investor's capital being tied up for years without regular dividend payments.

How Interest Accrues

Interest accrues annually on the note balance. With simple interest (most common), a $100,000 note at 3% annual interest accrues $3,000 per year. After two years, you owe $106,000 at conversion. After three years, $109,000.

Some notes specify compound interest, where interest is calculated on the principal plus previously accrued interest. This is less common in startup convertible notes but more punitive if it appears. A $100,000 note at 3% compound interest becomes $103,000 after year one, then $106,090 after year two (interest on $103,000). By year five, you owe $115,927 instead of $115,000 with simple interest.

Always check whether your note specifies simple or compound interest. Most founder-friendly notes use simple.

Real Example: How Interest Affects Conversion

Imagine you raise a $250,000 convertible note at 4% interest. You convert to equity at Series A after 2.5 years.

Principal: $250,000

Accrued interest: $250,000 × 4% × 2.5 years = $25,000

Total amount converting: $275,000

If the conversion price (after applying any cap or discount) is $3.33 per share, you issue 82,582 shares. If there were no interest, you'd issue 75,075 shares. Interest creates about 7,507 extra shares—roughly 0.3-0.5% of fully diluted cap table, depending on company size.

On a percentage basis, that's not massive. But on an absolute basis, interest is additional dilution that sneaks in often without founders fully considering it.

When Interest Matters Most

Interest matters most when conversion is delayed. A 3% rate over 1.5 years is roughly 4.5% total dilution. Over 4 years, it's 12% of principal. If you raise multiple notes with delayed conversions, interest compounds across all of them.

Interest also matters when combined with caps and discounts. An investor already getting a 20% discount plus a favorable cap is also earning 4% annual interest on top. Multiple benefits stack.

Interest matters least when you convert quickly (within 1-2 years) or when the company growth is dramatic (the interest becomes rounding error in the cap table).

Interest Rate Negotiation Strategies

Some investors propose interest rates as standard. Others are willing to negotiate. Here's what works:

Argue that caps and discounts are sufficient incentive. If you're already giving a 20% discount and a $2.5M cap, additional interest seems greedy. Many investors will accept 0-2% if other terms are favorable to them.

Propose a tiered structure. "We'll do 2% interest if you convert within two years. If conversion is delayed beyond year three, it steps up to 4%." This incentivizes faster conversion and limits founder dilution if you exit early.

Cap interest accrual at a maximum. "Interest accrues up to 5% total, then stops." This prevents runaway interest on old notes.

Tie interest to milestones. "Interest accrues at 2% annual if revenue is below $100K. At $100K+ revenue, it increases to 3%." This is investor-friendly (they earn more as you grow) but protects founders from excessive rates before you hit traction.

Zero Interest Notes

Some notes have zero interest. This is founder-friendly but rare unless you have strong negotiating position. Why would an investor accept zero interest when they could get 2-4%?

Reasons it happens: You have multiple investors and one agrees to 0% to win your attention. Your cap and discount are exceptionally favorable to the investor. You're in a highly competitive fundraise where investors concede on interest to get in.

If you have leverage, push for zero interest. It's only a few percent over a few years, but it's foundational—every little bit helps in your cap table.

Interest and Series A Due Diligence

Series A investors will scrutinize the terms on your convertible notes, including interest rates. If you have multiple notes with varying rates, that looks chaotic. If you have very high rates (7-8%), it signals desperation to investors—why were you paying such expensive debt?

Market-standard rates (2-4%) look clean. When discussing with Series A investors, have this conversation: "Our convertible notes have accrued interest of $X, which will convert as equity at Series A. We factored this into our dilution models."

Interest vs. Warrant Coverage

Some convertible notes include warrant coverage instead of interest. A warrant is an option to buy shares at a set price in the future. For example: "$100K note with 10% warrant coverage" means you get $100K now and warrants to buy shares equivalent to 10% of the note's value at Series A.

Warrants are often more dilutive than interest because they can last years beyond conversion. They're also more complex to model. Traditional interest is simpler and more founder-friendly than warrant coverage.

What Happens to Interest if the Note Doesn't Convert

Most convertible notes specify a maturity date (typically 3-5 years). If they haven't converted by maturity, the company usually must repay principal plus accrued interest in cash. This is the nightmare scenario—you owe real money.

In practice, if maturity is approaching without Series A, you either convert the note (a forced conversion), extend it (with the investor's agreement), or raise a bridge round. Repaying cash is rarely feasible for startups.

Make sure you have a clear path to conversion (Series A plan) before maturity. If Series A looks uncertain, renegotiate the maturity date or interest terms before time pressure forces unfavorable deals.

Modeling Interest in Your Pro Formas

Include accrued interest in your cap table projections. For each note, calculate interest based on your expected conversion timeline. If you're modeling Series A at year 2.5, include 2.5 years of accrued interest in the conversion amount.

Interest might not change your dilution picture dramatically, but it should be accounted for. A $500K round of convertible notes with 4% interest could add $20-40K to the total amount converting depending on timeline—that's measurable equity.

The Psychology of Interest

Founders often accept interest without question because it seems small. A 4% rate feels negligible compared to a 20% discount. But interest is "hidden" dilution—it doesn't show up visibly in cap table discussions, it just silently increases the conversion amount.

Don't ignore it. Fight for low interest rates (0-2%) just like you fight for caps and discounts. Investors expect to negotiate on all three terms.

Key Takeaways

• Convertible note interest typically ranges 0-8%, accruing annually until conversion
• Interest increases the total amount converting, resulting in additional founder dilution
• Effect is modest (usually 0.5-2% additional dilution) but worth negotiating
• Negotiate for low rates (0-3%) or tiered structures that tie rates to company milestones
• Include accrued interest in your pro forma models for accurate dilution projections

Frequently Asked Questions

Q: Is 5% interest considered high?
A: No, it's within market range. But 2-3% is more common for founder-friendly terms.

Q: Can interest be deferred until conversion?
A: Yes, that's standard. It's added to principal and converts into equity.

Q: What if the note matures before Series A?
A: You typically extend the note, convert it forcefully, or refinance with new capital. Repaying cash is rarely an option.

Q: Does interest count toward my annual cash burn rate?
A: No—it's not cash expense. It only matters at conversion when it increases the equity issued.

Q: Can I negotiate interest down after signing?
A: Not typically. Interest terms are fixed. Negotiate thoroughly before signing.