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About this tool
Density from mass and volume, with common unit conversions.
The Density Calculator divides mass by volume (ρ = m / V) to return density in g/cm³, converts the same figure to kg/m³, and tells you whether the material sinks or floats in water. Enter mass in grams and volume in cubic centimetres (millilitres) and you get the density to three decimal places plus the SI equivalent. It is built for students working physics and chemistry problems, makers checking a material sample, and anyone who has a weight and a displaced-water volume and needs the number in between.
Open Density Calculator on AltFTool — it loads instantly in your browser.
Enter the mass of the substance in grams in the Mass (g) field, which starts at 100
Enter the volume in the Volume (cm³ / mL) field, which starts at 50 — a volume of 0 replaces the result with the message Volume can't be zero
No calculate button is needed: the Result panel recomputes as you type, showing the density to three decimals in g/cm³ alongside a kg/m³ conversion and a vs water card reading sinks or floats, and the Copy or Download button saves that summary as density-calculator.txt
Reports g/cm³ and kg/m³ together, so lab work and SI-format answers come from the same measurement.
Compares the result against water at 1 g/cm³ and states outright whether the sample sinks or floats.
A volume of zero returns a clear message instead of an infinite or NaN result you might copy into a report.
Divide mass by volume: density = mass ÷ volume. With mass in grams and volume in cubic centimetres the answer comes out in g/cm³ — 100 g in 50 cm³ is 2.000 g/cm³.
Yes, one millilitre equals exactly one cubic centimetre, so you can enter a water-displacement reading in mL directly into the volume field. That equivalence is why the field is labelled cm³ / mL.
Multiply by 1000 — 1 g/cm³ is 1000 kg/m³. The calculator shows that conversion on its own row so you do not have to shift the decimal yourself.
It floats if its density is below about 1 g/cm³ and sinks above it, since fresh water is roughly 1 g/cm³ (1000 kg/m³) at room temperature. The comparison assumes a solid object in fresh water and ignores trapped air, hollow shapes and salinity, all of which change real-world buoyancy.
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