Convertible Note & Cap Table Math Guide for Massachusetts

What this calculator does

Run this scenario in DocketMath using the Convertible Note Cap Table calculator.

DocketMath’s Convertible Note & Cap Table Math Guide (calculator: convertible-note-cap-table) helps you translate the key economic terms of a convertible note into concrete ownership outcomes and updated cap table math—using the mechanics founders, investors, and counsel typically model for Massachusetts startups.

In plain terms, the calculator is designed to compute (and show the math behind) questions like:

• How many shares the note converts into at a given conversion price
• How a valuation cap changes the conversion price
• How the discount rate changes the conversion price
• What happens when both a cap and discount apply (the usual “more favorable to the note” approach is what you’ll model)
• How dilution flows through:

  • pre-money valuation assumptions
  • option pool / reserved shares (if you include them in your model)
  • existing shareholders
  • the noteholders post-conversion

Because you’re in Massachusetts, you may also be dealing with time-based obligations (e.g., documenting, enforcing, or litigating claims tied to documents). Massachusetts’ general civil limitation period is a helpful backdrop for planning, even if the calculator itself focuses on cap table outcomes.

For timing context (non-cap-table), Massachusetts generally provides a 6-year statute of limitations for contract-related claims:

• Mass. Gen. Laws ch. 277, § 63 — 6 years

  • Exception referenced in your jurisdiction data: exception V1
• Massachusetts appellate guidance also reflects shorter periods in specific contexts (jurisdiction data indicates):

  • Jenkins v. Jenkins, 15 Mass. App. Ct. 934, 935 (1983) — 3 years (exception M5)

You’ll see later how to keep your models internally consistent when documents, conversion triggers, and enforcement timelines matter.

When to use it

Use DocketMath’s convertible-note-cap-table when you have a convertible instrument and you need to model how it affects ownership. The calculator is most useful in these situations:

• **You’re raising a priced equity round (Series Seed, Series A, etc.)

  • You want to estimate how the note will convert at the round’s terms.
• You have both a valuation cap and a discount

  • You need to compare conversion prices and determine the more favorable result to noteholders (based on your note terms).
• You’re updating your cap table before investor due diligence

  • Many rounds require evidence that option pool assumptions, cap mechanics, and dilution are internally coherent.
• You’re reconciling multiple notes

  • Several notes may convert differently if they have different caps, discounts, or original issue prices.
• You’re planning for a scenario analysis

  • Example scenarios include: “cap binds,” “discount binds,” or “neither binds.”

A practical checklist to decide whether to run the calculator:

One more Massachusetts-specific reason to use a disciplined model: documentation and enforcement timelines can matter in disputes. Since Mass. Gen. Laws ch. 277, § 63 provides a 6-year general limitation period (with noted exceptions in your data), you’ll want your records to support the conversion math you’re asserting when agreements are later challenged.

If you’re ready to run the calculations, use the calculator here: /tools/convertible-note-cap-table.

Step-by-step example

Below is a worked example you can replicate in DocketMath. I’ll use numbers that match common convertible note structures and show how the outputs change as inputs change.

Example setup (single convertible note)

Assume:

• Startup is raising a priced round
• Note principal: $500,000
• Note has:

  • Valuation cap: $5,000,000
  • Discount: 20%
• Priced round terms:

  • Pre-money valuation: $8,000,000
  • Round price implies a $1.00 per share conversion basis (you can model price-per-share directly, or DocketMath can derive conversion price from valuation inputs depending on your input fields)
• Current capitalization (pre-money, prior to this round):

  • Common shares outstanding: 4,000,000
  • Preferred investors in the priced round (as part of the round financing): modeled via the round price and capitalization math (we’ll focus on note conversion into post-round fully diluted numbers)

Step 1: Compute the cap-based conversion price outcome

If the cap is $5,000,000 and the note converts as if the company were valued at the cap, then the note effectively receives shares as though the conversion valuation is $5,000,000 rather than the actual $8,000,000.

In a price-per-share framework:

• Conversion price at cap = (conversion valuation basis) / (fully diluted share basis used by the model)

How this appears in practice:

• If your model inputs are valuation-based, DocketMath will produce a cap conversion price (or directly a cap conversion share count) from the cap valuation relative to the post-money / share basis you provide.

Step 2: Compute the discount-based conversion price outcome

A 20% discount means the note converts at 80% of the price paid by new investors in the priced round.

So:

• Discount conversion price = round price × (1 − 0.20) = 0.80 × round price

Again, depending on your DocketMath input mode, you may either:

• Provide price-per-share for the round, or
• Provide enough capitalization detail for DocketMath to infer the round price

Step 3: Choose the note’s conversion price based on the note terms

Most convertible note agreements use a rule like “the holder receives the more favorable of the cap or discount conversion.” Because terms vary, DocketMath’s calculator is built to reflect the conversion logic consistent with the inputs you enter.

Your model comparison typically becomes:

• Cap conversion price = ___
• Discount conversion price = ___
• Final conversion price = the lower price (more favorable to noteholders)

Step 4: Convert principal into shares

Once the calculator has the final conversion price, it computes:

• Note conversion shares = note principal ÷ final conversion price

Example intuition (no need to guess exact share basis):

• If cap binds, the note likely converts more favorably (often more shares).
• If discount binds, the note converts at a discount to the round price (could be more or less favorable than cap depending on valuations).

Step 5: Update the cap table and compute ownership percentages

Now DocketMath updates the cap table:

• Add the converted note shares to the existing share pool (on the fully diluted basis the model uses).
• Recompute ownership percentages for:

  • common holders
  • preferred holders
  • noteholders (after conversion)

You’ll see outputs such as:

• Post-conversion share counts by holder/class
• Post-conversion % ownership
• Dilution percentages relative to pre-conversion ownership

Step 6: Validate the model assumptions

Before you finalize the cap table numbers:

• Confirm whether the option pool is included in the relevant share basis (many conflicts arise here).
• Confirm whether conversion uses:

  • original principal
  • adjusted principal (e.g., accrued interest, fees)
  • any conversion mechanics in your note

Common scenarios

Convertible notes don’t all behave the same way. Here are scenario patterns that commonly change the outcome you care about—along with how DocketMath helps you stress-test your assumptions.

1) Valuation cap binds (cap is more favorable than discount)

When the priced round valuation is high relative to the cap:

• The cap usually produces a lower effective conversion price than the discount.

What you’ll typically see:

• Larger share issuance to noteholders
• Noteholders’ ownership % rises
• Greater dilution to common/other holders

2) Discount binds (discount is more favorable than cap)

If the priced round valuation is low enough:

• The discounted round price can be better than the cap.

Result:

• Conversion shares may be smaller than the cap scenario
• Dilution impacts shift accordingly

3) Neither binds “as expected” (term mechanics or input mismatch)

Sometimes the math surprises you because:

• You entered the wrong pre-money valuation basis
• You double-counted an option pool
• You assumed a price-per-share that doesn’t align with the valuation inputs

Quick self-check using the calculator:

• Run the same scenario with option pool included/excluded
• Compare output changes—if results swing wildly, your share basis likely needs reconciliation

4) Multiple notes with different caps/discounts

If you have, for example:

• Note A: cap $5M, discount 20%, principal $500k
• Note B: cap $3M, discount 15%, principal $250k

You’ll likely see:

• Note B converts at a more favorable effective price, sometimes dominating dilution
• Post-conversion ownership varies significantly across noteholders

DocketMath is most valuable here because you can model each note’s conversion independently and observe their combined impact on the cap table.

5) Conversion trigger timing and documentation

While the calculator is cap table math, conversion disputes often become disputes about:

• how the triggering event was defined
• whether notice was provided
• whether amounts included principal only or principal plus accrued items

Massachusetts’ general 6-year limitation period provides a broader time horizon for many

Sources and references

Start with the primary authority for Massachusetts and confirm the effective date before relying on any output. If the rule has been amended, update the inputs and rerun the calculation.

• Mass. Gen. Laws ch. 156D, § 7.32

Related reading

• Inputs you need for convertible note cap table math in United States (Federal) — Input checklist with sourcing guidance
• Worked example: convertible note cap table math in North Carolina — Worked example with real statute citations
• Convertible note cap table math in California — Full how-to guide with jurisdiction-specific rules