Fill null (empty) cells in CSV data with a custom fill value. Clean datasets for analysis and migration — local processing, free, no signup.
Content reviewed October 2026 · About Toolzum
Validate CSV structure — flag rows with wrong column counts and empty cells before import. Catch bad rows locally — free, no signup.
Analyze CSV structure — column types, counts, unique values, and empty cells. Spot malformed rows and mixed types before import.
Generate arithmetic, geometric, and custom number sequences with sums. Fill spreadsheets and test series — free, local, no signup.
Profile CSV datasets — row counts, column types, null rates, value distributions. Scope data quality before analysis — local parsing, free, no signup.
Clean messy CSVs — trim whitespace, fix encodings, deduplicate rows, standardize blanks. Make client exports analysis-ready — local processing, free, no signup.
Empty and whitespace-only cells. Literal strings like 'null' or 'NA' are left untouched — only truly blank cells are filled.
One custom fill text applied to every empty cell — type your own or pick a preset like N/A, NULL, or 0. No mean/median or forward-fill modes.
No. Every empty cell in every column gets the same fill value. Split out columns you want to preserve first.
No — comma-separated values only. Semicolon, tab, or pipe files need converting to commas first.
No. All processing happens locally in your browser. No CSV data is sent to any server.
3: a missing phone, a missing email, and another missing phone across the demo rows — each replaced by the chosen token (N/A by default). Only whitespace-empty cells count; literal null text is left alone.
CSV Deduplicator
Remove duplicate rows from CSV data based on a specific column. Keep only unique values for cleaner datasets — local processing, free, no signup.
CSV Format Validator
Validate CSV structure — flag rows with wrong column counts and empty cells before import. Catch bad rows locally — free, no signup.
Data Format Converter
Convert data between JSON, CSV, XML, YAML, and TSV with structure preserved. Migrate configs across stacks without rewriting — local PapaParse/xml2js/yaml parsing, free, no signup.