Portfolio Rebalancing Calculator

Put each month's new money only into the parts of your mix that are below target, and buy nothing of what is above it, until every part is back on target.

In the example above, $50,000 holds 80% US stocks against a 60% target; adding $2,000 a month as VXUS $1,451 + BND $549 brings it back to 60/30/10 in 9 months, without selling anything.

Selling a fund that has grown can trigger capital gains tax, and every trade can cost a fee and a spread. Buying only with new money avoids both; how fast it works depends on how large your monthly amount is compared with the drift.

The plan reads each fund from its published asset mix and country split and places it in three parts: US stocks, international stocks and bonds. A fund that is 98% bonds counts as 98% bonds, a world fund that is 62% United States counts 62% of its stocks as US, and the cash inside a fund counts toward none of the three.

Each month, your new money goes only to the parts below target, in proportion to how far below they are, so every part reaches its target in the same month, usually with the same buys every month. In the last month, once the gaps are smaller than your monthly amount, the rest is split by your target mix. On target means every part within half a point of its target.

Prices are assumed flat: the plan shows what your purchases do on their own. Markets will move your mix along the way, so check it again every few months.

The sector cap (it starts at 30%) limits your largest sector, usually technology, which a market-cap index fund can hold a lot of. When two of your funds fill the same part of your mix, the plan buys the one with less of that sector; when no choice of fund brings the sector under the cap, the plan says so.

To see the countries and companies behind the three parts, see where your money really is.

Where the numbers come from

Each fund's place in the three parts and its sectors come from the funds' published country splits and asset mix via our market-data providers. Data as of October 23, 2026 for the example; funds you add are looked up when you add them.

Selling is the usual tool when a drift is too large for new money to close in a reasonable time, or when a sale costs no tax.

Many investors use tolerance bands instead of a calendar. A common one is the 5/25 rule: act when a part drifts 5 points from its target or a quarter of its target, whichever is smaller, so a 60% target allows 55–65% and a 10% target allows 7.5–12.5%.

A large drift against a small monthly amount can take years to close with new money alone. The calculator shows how long, and its 3- and 6-month amounts show what closing it sooner would take.

Inside a tax-advantaged account such as an IRA, a 401(k) or an ISA, a sale triggers no capital gains tax, so rebalancing there costs only the trade. In a taxable account, selling a fund that has grown can trigger tax.

They are three common target mixes, and the calculator starts from any of them.

• Three-fund: 60% US stocks, 30% international stocks and 10% bonds, the classic mix of a US total-market fund, an international fund and a bond fund such as VTI, VXUS and BND.
• 60/40: 60% stocks and 40% bonds, with the stocks split 60/40 between US and international: 36% US, 24% international, 40% bonds.
• All-world: 62% US and 38% international stocks with no bonds, roughly the country split of a global market-cap index.

Funds that fill the same part of a mix can cost very different amounts: check your portfolio's weighted expense ratio.

Investing from the EU, where most US-listed ETFs cannot be bought by private investors? Find the UCITS equivalent of a US ETF.