How to Track Your Investment Portfolio’s Asset Allocation in a Spreadsheet

You’ve got money invested across a few accounts, and you have a rough idea you should be “diversified” — but if someone asked what percentage of your portfolio is actually in stocks versus bonds versus cash right now, you couldn’t say. And you definitely couldn’t say whether a strong run in one holding has quietly left you more concentrated and more exposed than you meant to be. This guide shows you how to see your exact asset allocation in a spreadsheet, and how to know when it’s drifted far enough that you should rebalance.

Allocation is the part of investing you actually control. You can’t control returns, but you can control how your money is split — and that split drives most of your risk. A portfolio you think is balanced but is really 85% in one asset class is taking risk you never signed up for. Tracking allocation turns that from a blind spot into a number you glance at once a quarter.

Step 1: Give Every Holding an Asset Class

List each investment with its current value and tag it with an asset class. Keep the classes simple — for most people, four buckets are enough:

• Stocks — individual shares, stock ETFs and mutual funds, the equity portion of target-date funds
• Bonds — bond funds, individual bonds, the fixed-income side of target-date funds
• Cash — money market, high-yield savings you count as part of your investing, settlement cash
• Other — crypto, commodities, REITs, anything that doesn’t fit the first three

If a holding is a blended fund (like a target-date fund that’s 80% stocks / 20% bonds), you can split it across two rows for precision, or just tag it by its dominant class if you want to keep things simple.

Step 2: Calculate the Percentages

Sum the total value, then divide each holding by that total. Group by class and you have your allocation. A worked example:

Roll those up by class and your actual allocation is: Stocks 76.8%, Bonds 10.5%, Cash 8.1%, Other 4.7%. That’s the number you couldn’t have named a minute ago.

Step 3: Put Your Target Next to Your Actual

A percentage on its own doesn’t tell you whether to act. The magic is comparing your actual allocation to your target. Add a target column:

Now it’s obvious. This investor is over-weighted in stocks and well under their bond target — they’re carrying more risk than they intended, probably because stocks ran up. The “drift” column is the whole point: it converts a vague feeling into a clear signal.

Step 4: Use a Threshold, Not a Calendar

You don’t need to rebalance on a schedule. A common, low-effort rule is the 5% threshold: only act when an asset class drifts more than about 5 percentage points from its target. In the example above, stocks (+6.8%) and bonds (−9.5%) have both crossed that line, so this portfolio is due for a rebalance; cash and other are close enough to leave alone.

Threshold rebalancing means you check periodically — quarterly is plenty for most long-term investors — but only trade when the drift actually warrants it. That keeps you from fiddling with your portfolio every time the market twitches, which is where most people quietly hurt their returns.

Step 5: Always Look Across All Accounts

The single most common allocation mistake is looking at one account in isolation. Your true allocation is across everything combined — 401(k), IRA, brokerage, HSA. A conservative 401(k) and an aggressive brokerage account might average out to exactly your target, or they might stack up in the same direction and leave you far off. You only find out by pulling every investment account into one allocation view.

That’s exactly what a combined net worth and investment tracker spreadsheet does: its portfolio tab totals your holdings across all accounts and shows the allocation percentages automatically, so the mix you see reflects your whole portfolio. The Net Worth & Investment Tracker keeps that allocation view right alongside your net worth, so the same monthly update tells you both where you stand and whether your investments are still balanced.

For the full system this fits into, see the pillar: how to track net worth and investments in one spreadsheet. And if your accounts are scattered across several institutions, here’s how to pull them all into one tracker.

The Bottom Line

Asset allocation is the part of investing you control, and it’s the biggest driver of your risk — so it’s worth actually looking at. Tag every holding with an asset class, calculate each one’s percentage, and put your target next to your actual so the drift is obvious. Use a threshold like 5% to decide when to rebalance instead of trading on a calendar, and always run the numbers across all your accounts at once. A spreadsheet turns “am I diversified?” from a hopeful guess into a number you can check in ten seconds.