How Many Shares Can I Buy?
Share Affordability Calculator.
Enter your budget and a share price to instantly see the maximum shares you can buy, the total cost including brokerage, and how much cash is left over.
How Many Shares Can I Buy?
Enter your budget and the share price
Shares You Can Afford
Whole shares, cost, and leftover cash
Enter your budget and share price to see how many shares you can buy
How Many Shares Can I Buy With My Budget?
The number of shares you can buy is simply your available cash divided by the price of one share, rounded down to a whole share (unless your broker supports fractional shares). Any flat brokerage fee is taken out of your budget first, so a commission reduces the cash left for shares.
Shares Affordability Formula
Shares = floor((Budget − Brokerage Fee) ÷ Share Price)Round down to a whole share unless your broker allows fractional buying.
Worked Example
- Budget: $5,000
- Share price: $187.50
- Brokerage fee: $0 (zero-commission broker)
- Shares = floor(5000 ÷ 187.50) = 26 shares
- Total cost = 26 × $187.50 = $4,875, leaving $125 in cash
Whole Shares vs Fractional Shares
Traditional brokers sell shares in whole units. You buy as many full shares as your budget allows and keep the rest as cash.
Brokers like Robinhood, Fidelity and Interactive Brokers let you invest an exact dollar amount, so you can put your whole budget to work with no leftover cash.
Frequently Asked Questions
How do I calculate how many shares I can buy?▾
Divide your available budget (after any brokerage fee) by the current share price, then round down to the nearest whole share. Formula: Shares = floor((Budget − Fee) ÷ Share Price). For example, with a $5,000 budget, a $187.50 share price and a $0 fee, you can buy floor(5000 ÷ 187.50) = 26 shares, costing $4,875 and leaving $125 in cash.
Can I buy a fraction of a share?▾
Many brokers (such as Robinhood, Fidelity, and Interactive Brokers) now support fractional shares, letting you invest an exact dollar amount rather than a whole number of shares. The calculator shows both the maximum whole shares and the fractional-share equivalent so you can use whichever your broker supports.
Do brokerage fees change how many shares I can buy?▾
Yes. Any flat commission or brokerage fee is deducted from your budget before shares are counted, so a fee reduces the cash available for shares. Most large US brokers are now zero-commission for stocks, but some markets and brokers still charge per-order fees — enter yours in the optional fee field for an accurate result.
Should I invest my whole budget in one stock?▾
Concentrating an entire budget in a single stock raises risk. Many investors spread a budget across several positions, or buy in tranches over time (dollar-cost averaging) rather than all at once. Use this calculator to size each position, then the Stock Averager to model averaging in over multiple buys.