mol/L (M) to wt% conversion
Converting M and wt% requires both molar mass and solution density. If density is missing, the tool still returns any density-free results first.
Concentration Converter (Density-aware)
Convert M (mol/L), m (mol/kg solvent), wt%, vol%, and ppm at the same time.
When a conversion needs density or molar mass, the result area tells you exactly what is missing and which basis was used.
Explicit ppm basis and assumptions
Shows results that do not need density first
Batch paste for lab, manufacturing, and QC work
Copy, CSV export, and share URL
What this page covers
ppm conversion with explicit basis
ppm can mean mg/kg, mg/L, or uL/L depending on context. This page makes you choose the basis and keeps that basis visible in the result.
Molality converter: mol/kg to M
Molality and molarity depend on both molar mass and density. Missing inputs are shown as actionable reasons instead of generic errors.
Batch conversion for pasted tables
Paste TSV or CSV rows, apply shared defaults when columns are blank, and export the converted table again as CSV.
How to use
- Choose the input format and enter the value.
- Select the ppm basis you want to use in the result.
- Add molar mass or density only if the result tells you it is needed.
- Review all five outputs together and check the assumptions chips above the results.
- Switch to Batch mode when you want to paste TSV or CSV rows from a spreadsheet.
Examples
M to wt% and ppm
Input
0.1 M, MW = 58.44, solution density = 1.00 g/mL, ppm basis = w/w
Output
wt% = 0.584, ppm = 5844
wt% to ppm(w/w)
Input
1 wt%
Output
10000 ppm (w/w)
ppm(w/v) to M
Input
500 ppm (w/v), MW = 58.44
Output
0.00856 M
Batch paste
Input
Paste rows from Excel or Google Sheets
Output
Each row returns M, m, wt%, vol%, ppm, and any missing inputs
Glossary
M (molarity)
Moles of solute per liter of solution.
m (molality)
Moles of solute per kilogram of solvent.
wt% (w/w)
Mass fraction of solute in the whole solution, shown as percent.
vol% (v/v)
Volume fraction of solute in the final solution, shown as percent.
ppm
A concentration label whose exact meaning depends on the chosen basis, such as mg/kg, mg/L, or uL/L.
Formulas and assumptions
wt% = 100 × (M × MW) / (rho × 1000)M = (w × rho × 1000) / MWm = 1000 × M / (1000 × rho − M × MW)ppm(w/w) = 1e6 × wM = (rho_solute × v × 1000) / MW
Frequently Asked Questions
What happens if I do not know the density?
The converter still shows any results that do not need density, such as wt% to ppm(w/w). For results that do need density, it shows a reason such as "Needs: solution density" instead of failing the whole calculation.
What ppm definition does this tool use?
ppm can be defined as w/w (mg/kg), w/v (mg/L), or v/v (uL/L). This tool lets you choose the basis and displays that basis in the result area and copied output.
Can I convert many rows at once?
Yes. Batch mode accepts TSV and CSV paste. If row columns are blank, the shared defaults above the paste area are used.
How accurate is vol% conversion?
vol% (v/v) is converted with the density of the pure solute. If the mixture is non-ideal or shows volume contraction, the result can differ from the real system.
Notice
- ppm has multiple definitions. Always confirm whether your source means w/w, w/v, or v/v.
- Density depends on temperature. If precision matters, enter the density measured at the relevant temperature.
- vol% (v/v) conversions use the density of the pure solute and ignore non-ideal mixing effects such as volume contraction.
- This tool assumes a single solute. Multi-component systems need a different treatment.