Free tool

NAV File Validator

Check your CSV files for correct headers, date formats, and values before uploading. PortBlend processes all files locally in your browser.

Headers Check

Your file needs exactly two columns. We match aliases like date, nav, close, and value.

Date Check

Dates must be sorted ascending with no duplicates. Standard ISO format (YYYY-MM-DD) is highly recommended.

Numeric Values

Values must be clean numbers. Remove any currency symbols, commas, or empty cells before uploading.

CSV File Validator— paste up to 10 rows to check your file

Accepted column names

Type	Aliases
Date column	date, date_time, tradedate, trade_date, datetime, timestamp, period, week, month
NAV column	nav, nav_value, equity, cum_nav, cumnav, cumulative_nav, close, value, portfolio_value

Accepted date formats

Format	Example	Status
`YYYY-MM-DD`	2015-01-01	Recommended
`DD-Mon-YYYY`	01-Jan-2015	Accepted
`DD-MM-YYYY`	01-01-2015	Accepted
`DD/MM/YYYY`	01/01/2015	Accepted
`YYYY/MM/DD`	2015/01/01	Accepted
`DD-Mon-YY`	01-Jan-15	Accepted

Why file validation matters

Different brokerages and charting tools export portfolio historical data in wildly different layouts. Some include multiple columns (like open, high, low, close, volume), some use custom header names, and others format dates in ambiguous ways.

By validating your files using this browser tool before trying to upload them, you can pinpoint issues like misplaced columns, duplicate dates, or non-numeric cells immediately.

Run your portfolio analysis now

Once your NAV files are formatted correctly, upload them to run Drawdown Dynamics or blend them together to analyze combined historical drawdowns.

Go to PortBlend App View File Format Docs

Completely free. Guest uploads require no email registration.