Vanguard Portfolio Watch

Vanguard Portfolio Watch is a tool in the Vanguard website for Vanguard clients. It breaks down your asset allocation (including non-Vanguard funds if you list them), and gives cautions if your portfolio is too far from Vanguard's recommendations (too much in tax-inefficient funds in taxable accounts, unusually high or low weight to international stocks, overweight of large-cap, small-cap, growth, or value). A caution from Portfolio Watch does not mean that you are doing something wrong, but that you should be sure that what you are doing is deliberate.

The tool can be accessed from here (Portfolio analysis), but you must have an account to use the tool.

Cautions
Vanguard Portfolio Watch does not break down most funds into subclasses properly as it treats most funds as being entirely in their primary stock category rather than breaking the fund down into its component sub-classes. For example, if you have a fund which is 70% large-cap stocks and 30% mid-cap and small-cap stocks, Portfolio Watch may treat the fund as 100% large-cap and incorrectly conclude that you are overweighting large-caps.