Whole Share Dividend Reinvestment
Model fixed dividends per payment, whole share purchases and retained cash over three years, with an estimate of the first purchase time.
How whole share reinvestment works
Enter a fixed share price, dividend per share for one payment, starting shares and payment frequency. Each payment pays the shares held immediately before that payment. The available dividend cash buys as many whole shares as the model permits at the fixed price.
Cash too small for another whole share remains in the model and joins the next payment, without interest. Newly purchased shares first contribute dividend income at the following payment. The projection shows all payments across three years, with payment number and elapsed months kept separate.
First purchase timing assumes the next payment arrives after one complete interval. Before the first purchase, holdings and each payment's income are unchanged. The required payment count is rounded up and converted to months. A first payment already large enough to buy a share still waits one interval.
This is a hypothetical whole share and retained cash policy, not a simulation of every dividend reinvestment plan. Some real plans support fractional shares. Actual purchase prices, eligibility, charges, taxes and payment dates depend on the plan. The fixed price model also omits any price adjustment when a dividend is paid.
Step by step
- Enter a fixed purchase price, dividend per share per payment, starting shares and payment frequency.
- Review the first payment, optional rounding top up and first purchase timing.
- Follow every projected payment to see whole share purchases and the cash carried into the next payment.
Worked example
Use a fixed price of 150 USD, a dividend of 0.50 USD per share per payment, 100 starting shares and quarterly payments. The first income is 50 USD, buying zero shares and leaving 50 USD cash. The optional top up is 100 USD, but the projection does not add it.
The second payment raises cash to 100 USD. The third raises it to 150 USD, buys one share and leaves zero cash at month nine. The fourth income is 101 × 0.50 = 50.50 USD. After twelve quarterly payments, month thirty six has 104 shares and 9 USD retained cash. Zero discarded cash keeps the timing and projection consistent.
When to use this calculator
Inspect how fixed per payment dividends and retained cash accumulate into whole share purchases under a stated hypothetical policy.
Use the payment table to check units and cash handling. Compare actual plan terms, dividend uncertainty and investment returns separately.
Common interpretation errors
Do not put annual dividends or a yield percentage into the per payment dividend field. Changing frequency does not automatically convert that amount to preserve an annual total.
Do not call every payment number a month, assume a zero top up guarantees a share, or treat fixed dividend cash as risk free profit without considering share price changes.
Payment and retained cash formulas
Payment income = shares before purchase × dividend per share per payment
Available cash = retained cash from prior payments + current payment income
Whole shares purchased = floor(available cash / fixed share price)
Ending shares = prior shares + whole shares purchased
Retained cash = available cash − purchased shares × fixed price
First purchase months = ceil(fixed price / first payment income) × months per payment, when income is positive
Optional first payment top up = ceil(first payment income / fixed price) × fixed price − first payment income
Payments per year are twelve, four or one; months per payment are one, three or twelve. The optional top up only describes rounding the first payment's purchase up and is never contributed. A zero first income has no finite first purchase time. Whole share quantities use decimal division of modeled cash and price amounts; monetary results are rounded only for display. Purchases and aggregate shares must remain within the supported numeric range.
Scope and limitations
Price and dividend per payment are fixed assumptions, not quotes or payout forecasts. The model ignores dividend cuts or growth, price movements and dividend price adjustments, taxes, fees, cash interest, fractional new purchases, actual payment eligibility and external contributions. It is not total investment return, a broker execution model or a recommendation to reinvest. Three year rows use hypothetical regular intervals. Unsupported purchase quantities, share totals and numeric projections are withheld.
Key terms
- Dividend per payment
- The assumed cash distribution per existing share at each modeled payment, before taxes or charges.
- Retained dividend cash
- Unused dividend money carried to the following payment without interest after whole share purchases.
- First purchase time
- The number of hypothetical months from now until accumulated dividends first buy a whole share, assuming the first payout follows one full interval.
Related comparisons
Yield on Cost compares annual dividends with original and current prices. This tool instead uses a per payment dividend and whole share cash mechanics; it does not calculate a complete investment yield.
A compound savings model can assume fractional growth or interest. Here only whole share purchases change future dividend income, and leftover cash earns nothing.
FAQ
Is the dividend input an annual amount or one payment?
It is the dividend per share for one payment. Quarterly 0.50 means four assumed payments of 0.50 each year, not an annual 0.50 split into four. Changing frequency while holding this input constant changes the annual dividend assumption.
What happens to cash that cannot buy a whole share?
It is retained without interest and combined with the next dividend payment. The projection does not discard it. This makes waiting for the first purchase consistent with the modeled cash account.
Why does the first purchase take time even if one payment is enough?
The timeline begins before the first payment, which arrives after one full monthly, quarterly or annual interval. It is not a model of cash already received today or a known next payment date.
Does a zero optional top up mean I can buy a share?
No. It means the first payment's calculated purchase is already a whole number. That includes a zero dividend and zero shares purchased. Check the actual whole share count and the timing output separately. The top up is not added to any projected payment.
Does this match my broker's reinvestment plan?
Not necessarily. This model purchases only whole shares and retains unused cash. Real plans may buy fractional shares and apply different timing, prices, eligibility or charges. Check the plan's terms before comparing its actual transactions.
Related tools
Compare annual dividend yields, explore savings growth with different assumptions, or separate investment return from cash distributions.