What is the difference between density and specific gravity?

Density is mass per unit volume and carries units (kg/m³ or g/cm³). Specific gravity (also called relative density) is the ratio of a substance's density to a reference — water at 4 °C, 1000 kg/m³ — so it is a pure number with no units. Numerically, an object's specific gravity equals its density in g/cm³: aluminium at 2700 kg/m³ = 2.7 g/cm³ = specific gravity 2.7. This tool shows you the floats-or-sinks ratio against water, which is exactly specific gravity, so divide the kg/m³ result by 1000 to read it off.

Why does an object float or sink in water?

An object floats when its average density is less than the fluid it sits in. Fresh water is 1000 kg/m³, so anything below that floats (ice at 917, ethanol at 789, cork at 240) and anything above sinks (aluminium 2700, iron 7874, gold 19320). It is average density that matters, not the material alone — a steel ship floats because its hull encloses air, dropping the whole vessel's average density below water even though solid steel sinks. The tool's verdict uses the SI density of your case and compares it against 1000 kg/m³.

How do I convert g/cm³ to kg/m³?

Multiply by 1000: 1 g/cm³ = 1000 kg/m³, because a gram is 0.001 kg and a cubic centimetre is 0.000001 m³, and dividing those gives a factor of 1000. So water is 1 g/cm³ = 1000 kg/m³, and aluminium is 2.7 g/cm³ = 2700 kg/m³. g/mL is identical to g/cm³ (1 mL ≡ 1 cm³). Just pick the density unit from the dropdown and the tool does the conversion exactly — it normalizes to kg/m³ internally so you never multiply by the wrong power of ten.

Does temperature affect density?

Yes. Most substances expand when heated, so their volume rises while mass stays fixed, which lowers density. Water is the famous exception: it is densest at about 4 °C (1000 kg/m³) and gets less dense both above and below that, which is why ice (917 kg/m³) floats. The presets here use room-temperature or 4 °C reference values for clean comparison; for precise lab work at another temperature, look up the density at that temperature and type it in directly rather than relying on the preset.

Can I solve for mass or volume, not just density?

Yes — that is the whole point of the solve-for tabs. Pick 'Mass (m)' and enter a density and a volume to get m = ρ·V (useful for 'how heavy is this block of aluminium'). Pick 'Volume (V)' and enter a mass and a density to get V = m/ρ ('what volume does 500 g of gold occupy'). Pick 'Density (ρ)' for the classic m/V. The input you are solving for is hidden so you only ever fill the two knowns, and each field has its own unit dropdown.

Check a physics lab density measurement

You measured a metal cylinder at 500 g and 185 cm³ in lab. Pick the density mode, enter 500 g and 185 cm³, and read ~2703 kg/m³ — about 2.7 g/cm³. Click the aluminium preset (2700) to confirm you have an aluminium sample, not a heavier alloy. Because the tool normalizes g and cm³ to SI before dividing, your reported figure matches what the marker computes by hand, with no unit slip.

Find how heavy a block of a known material is

You need the mass of a 0.5 m³ concrete slab. Switch to the mass mode, click the concrete preset (2400 kg/m³), enter the volume as 0.5 m³, and get 1200 kg = 1.2 tonnes. Swap the preset to oak (750) to see how much lighter the same volume of wood would be. The unit dropdowns let you read the answer in kg without converting from grams by hand.

Work out the volume a given mass occupies

A jeweller has 100 g of gold and wants its volume for a mould. Use the volume mode, click the gold preset (19320 kg/m³), enter 100 g, and read ~5.18 cm³ — gold is dense, so even 100 g is a small lump. Compare with silver (10490) by clicking that preset: the same mass takes nearly twice the volume, which is why counterfeit "gold" bars are often too big.

Predict whether something floats before testing it

A student wonders if a chunk of ice will float in seawater. Enter ice's density (917 kg/m³) or click the preset, and the verdict says it floats and shows the ratio to fresh water (0.917×). Seawater (1025) is denser still, so ice floats even higher in the sea — the tool's water reference plus the seawater preset lets you reason about both fluids in seconds.

Teach the ρ = m / V triangle in class

When teaching the density triangle, switch between the three solve-for tabs to show that the same relation gives density, mass, or volume depending on what is unknown. Project the page, type 1000 g and 1000 mL for water, and the result lands on 1000 kg/m³ — a clean confirmation that one litre of water is one kilogram, which students remember better than the formula alone.

Density Calculator — solve ρ = m / V for any unknown, with units & substance presets

Solve ρ = m / V for density, mass, or volume · mixed units (g, kg, lb, mL, L, cm³, gallon) · 20 substance presets · floats-or-sinks verdict — all browser-only

Runs locally
Category Calculator
Best for Getting a realistic range before a purchase, plan, workout, or schedule decision.

ρ = m / V

Mass

Volume

Result

2702.7 kg/m³

Sinks in water · 2.7027× the density of water

Common substances (click to fill density)

What this tool does

A density calculator built around the relation ρ = m / V, where you pick which of the three quantities you want and supply the other two. Solving for density divides mass by volume; solving for mass multiplies density by volume (m = ρ·V); solving for volume divides mass by density (V = m/ρ). The part that actually saves you from arithmetic mistakes is the unit handling: enter mass in mg, g, kg, oz, or lb, volume in mL, L, cm³, m³, or US gallons, and density in g/cm³, kg/m³, or g/mL, and every value is normalized to SI base units (kg, m³, kg/m³) before the single divide or multiply, then the answer is converted back into the output unit you chose. No more silently mixing g/cm³ with mL. Twenty substance presets — water, ice, ethanol, olive oil, aluminium, steel, iron, gold, mercury, lead, and more — fill a known density with one click so you can check your result against a reference. A floats-or-sinks verdict compares the result against fresh water (1000 kg/m³) and tells you the ratio. The full calculation lives in a shareable URL, and a copy button hands you the formatted answer. Everything runs client-side.

Tool details

Input: Text + Numbers; The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output: Live result + Copy; The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy: Browser-side processing; The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share: Shareable URL state; Key settings are encoded in the URL so another person can reopen the same setup.
Performance budget: Initial JS <= 11 KB; No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit: Calculator · Student; Category and role tags drive related tools, internal links, and quick fit checks.

How to use

1. Input

Paste or drop your content into the tool panel.
2. Process

Click the button. All processing is local in your browser.
3. Copy / Download

Copy the result or download to disk in one click.

How Density Calculator fits into your work

Use it for fast estimates, comparisons, and planning numbers before you make the final call.

Calculation jobs

Getting a realistic range before a purchase, plan, workout, or schedule decision.
Comparing scenarios by changing one input at a time.
Turning rough assumptions into a number you can discuss.

Calculation checks

Double-check units, dates, rates, and rounding assumptions.
Treat health, finance, tax, and legal outputs as planning aids, not professional advice.
Save the inputs that produced an important result so you can reproduce it later.

Good next steps

These links move the current task into a more complete workflow.

Real-world use cases

Check a physics lab density measurement
You measured a metal cylinder at 500 g and 185 cm³ in lab. Pick the density mode, enter 500 g and 185 cm³, and read ~2703 kg/m³ — about 2.7 g/cm³. Click the aluminium preset (2700) to confirm you have an aluminium sample, not a heavier alloy. Because the tool normalizes g and cm³ to SI before dividing, your reported figure matches what the marker computes by hand, with no unit slip.
Find how heavy a block of a known material is
You need the mass of a 0.5 m³ concrete slab. Switch to the mass mode, click the concrete preset (2400 kg/m³), enter the volume as 0.5 m³, and get 1200 kg = 1.2 tonnes. Swap the preset to oak (750) to see how much lighter the same volume of wood would be. The unit dropdowns let you read the answer in kg without converting from grams by hand.
Work out the volume a given mass occupies
A jeweller has 100 g of gold and wants its volume for a mould. Use the volume mode, click the gold preset (19320 kg/m³), enter 100 g, and read ~5.18 cm³ — gold is dense, so even 100 g is a small lump. Compare with silver (10490) by clicking that preset: the same mass takes nearly twice the volume, which is why counterfeit "gold" bars are often too big.
Predict whether something floats before testing it
A student wonders if a chunk of ice will float in seawater. Enter ice's density (917 kg/m³) or click the preset, and the verdict says it floats and shows the ratio to fresh water (0.917×). Seawater (1025) is denser still, so ice floats even higher in the sea — the tool's water reference plus the seawater preset lets you reason about both fluids in seconds.
Teach the ρ = m / V triangle in class
When teaching the density triangle, switch between the three solve-for tabs to show that the same relation gives density, mass, or volume depending on what is unknown. Project the page, type 1000 g and 1000 mL for water, and the result lands on 1000 kg/m³ — a clean confirmation that one litre of water is one kilogram, which students remember better than the formula alone.

Common pitfalls

Mixing units silently — entering grams but cubic metres. Use the per-field unit dropdowns; the tool converts everything to SI before computing so you never multiply by the wrong power of ten.
Confusing density with weight. Density is mass per volume and does not depend on object size; a small lead pellet and a big lead brick share the same density.
Assuming a material's solid density decides if a shape floats. Floating depends on average density — a hollow steel hull floats because it encloses air, even though solid steel sinks.

Privacy

Every calculation — the divide or multiply for ρ = m/V, all unit conversions, and the floats-or-sinks check — is plain JavaScript running in your browser tab. No mass, volume, or density value is sent anywhere, there is no logging, and there is no external API call. The shareable URL encodes your inputs and chosen units in the query string so a "share link" reproduces the exact calculation; for ordinary physics or engineering figures that is harmless, and your last-used units are remembered only in this browser's local storage.

FAQ

Tool combos

Folks in your role tend to reach for these alongside this tool.

Browse all tools for this role

Density Calculator — solve ρ = m / V for any unknown, with units & substance presets

Result

Common substances (click to fill density)

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How Density Calculator fits into your work

Calculation jobs

Calculation checks

Good next steps

Real-world use cases

Check a physics lab density measurement

Find how heavy a block of a known material is

Work out the volume a given mass occupies

Predict whether something floats before testing it

Teach the ρ = m / V triangle in class

Common pitfalls

Privacy

FAQ

Unit Converter

Scientific Calculator

Percentage Calculator

Air Conditioner BTU Calculator

Scientific Notation Converter

24-Point Solver & Game

555 Timer Calculator

A1C to Blood Glucose Calculator

Add Days to Date Calculator

Age Calculator

Age Difference Calculator

AI Token Counter