Molarity Calculator — Moles, Mass and Solutions

← Research ReefThe Creative Island · Island 13

How many grams make a 1 M solution? Mass ↔ moles ↔ molarity, any direction.

Solve for Mass of solute (g) Molarity (M) Volume (L)

Molar mass (g/mol)

Molarity (mol/L)

Volume (L)

Mass (g)

Common molar masses: NaCl 58.44 · glucose 180.16 · KOH 56.11 · CaCO₃ 100.09 (g/mol).

How to use this tool

1. Choose what to solve for — mass, molarity or volume.
2. Enter the molar mass from the label (or the sum of atomic weights).
3. Fill the two known remaining fields and press Calculate.

Example

0.5 L of 0.1 M NaCl: mass = 0.1 × 0.5 × 58.44 = 2.92 g — weigh 2.92 g, dissolve, top up to exactly 500 mL.

The formula

moles = molarity × volume  |  mass = moles × molar mass

What the result means

Molarity counts particles, not grams — one mole is 6.022 × 10²³ molecules, which is why chemists weigh by molar mass: it makes different substances comparable by the number of molecules, not by the number on the scale.

Frequently asked questions

Where do I find the molar mass?

On every reagent bottle label. Or compute it: sum the atomic weights from the formula (NaCl = 22.99 + 35.45 = 58.44 g/mol).

Why does volume use litres?

Because molarity is defined as moles per litre. Working in mL everywhere is fine — just convert: 250 mL = 0.25 L.

Molarity vs molality?

Molarity is per litre of solution; molality is per kilogram of solvent. Molarity rules the typical bench; molality appears when temperature changes volume.

Is my lab data private?

Yes — the calculation happens in your browser.

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Explore the island world

• Research Reef — the island where this tool lives.
• The Main Island — drive the boat, explore the whole world.
• The 90s Kids Island — where most of us started.

Privacy & data: this tool runs entirely in your browser — nothing you type is uploaded, saved or sent anywhere. · Disclaimer: calculations use standard scientific formulas — for lab, safety or field decisions, always double-check with official protocols. · Privacy Policy · Disclaimer

Dilution Calculator — C1V1 = C2V2 Solver

← Research ReefThe Creative Island · Island 13

The lab's favorite equation — solve C1V1 = C2V2 for whatever you're missing.

Solve for Volume of stock needed (V1) Final volume to prepare (V2) Achieved concentration (C2)

C1 (stock conc.)

V1 (stock volume)

C2 (target conc.)

V2 (final volume)

How to use this tool

1. Choose what to solve for — that field is disabled and the others feed it.
2. Enter the known values — keep units consistent (all mL, or all L; all M or all mg/mL).
3. Press Calculate — the answer includes the practical instruction (how much stock, how much diluent).

Example

10 M stock into 0.5 M, final volume 100 mL: V1 = 100 × 0.5 ÷ 10 = 5 mL stock + 95 mL water — a 1:20 dilution.

The formula

C1 × V1 = C2 × V2 (the amount of solute is identical before and after diluting)

What the result means

Dilution conservs solute: whatever molecules were in the stock are all still there after you add water — spread through a bigger volume, hence a smaller concentration. The dilution factor (C1/C2) tells you the ratio at a glance, which is how bench protocols are usually written ('make 1:20').

Frequently asked questions

Does it matter which units I use?

Only consistency does: V1 and V2 in the same unit, C1 and C2 in the same unit. The equation is pure ratios.

Why does 5 mL stock + 95 mL water, not + 100 mL?

Because the final volume is what counts. 5 mL + 95 mL = 100 mL total; adding 100 mL of water would give 105 mL and a wrong concentration — the classic beginner's error.

Can it handle serial dilutions?

Not in one step — compute each stage separately, chaining the output C2 into the next C1. That's also the honest way to catch pipetting-error accumulation.

Is this lab data uploaded?

No — everything is computed in your browser.

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• Research Reef — the island where this tool lives.
• The Main Island — drive the boat, explore the whole world.
• The 90s Kids Island — where most of us started.

Privacy & data: this tool runs entirely in your browser — nothing you type is uploaded, saved or sent anywhere. · Disclaimer: calculations use standard scientific formulas — for lab, safety or field decisions, always double-check with official protocols. · Privacy Policy · Disclaimer

Scientific Calculator — Free Online with sin, cos, log

← Research ReefThe Creative Island · Island 13

A proper scientific calculator in your browser — trigonometry, logarithms, powers and pi, all computed locally.

Expression

Functions in radians: sin(1.5708) ≈ 1. Use deg conversions like sin(30×3.14159÷180) for degrees, or type sin(0.5236) for sin(30°).

How to use this tool

1. Type an expression or use the function buttons to insert sin, cos, log and friends.
2. Press = (or Enter). Angles are in radians.
3. Press a function button while your cursor is placed to insert exactly there.

Example

sqrt(2) + ln(2.718281828) → 1.4142 + 1 ≈ 2.4142. For degrees: sin(30°) = sin(0.5236 rad) ≈ 0.5.

The formula

expression evaluated with whitelisted Math functions; radians assumed (multiply degrees by π/180)

What the result means

This is real floating-point math with standard library functions — the same results a handheld calculator gives, including the radian convention for trigonometry. Angles in mathematics and physics default to radians; degrees are a convenience of daily life.

Frequently asked questions

Why radians and not degrees?

Radians are the natural unit of mathematics — derivatives and series only work cleanly in radians. Multiply your degrees by π/180 (or 0.01745) before feeding trig functions.

What is the difference between log and ln?

log is base-10 (log(100) = 2), ln is natural base-e (ln(e) = 1). Chemistry uses both; spreadsheets call them LOG10 and LN.

Can I use it for exams?

Use it to check your work — most exams want the method shown, and this tool deliberately shows you only the answer. Learning happens in the steps.

Is my input recorded?

No — evaluation happens locally in your browser.

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Explore the island world

• Research Reef — the island where this tool lives.
• The Main Island — drive the boat, explore the whole world.
• The 90s Kids Island — where most of us started.

Privacy & data: this tool runs entirely in your browser — nothing you type is uploaded, saved or sent anywhere. · Disclaimer: calculations use standard scientific formulas — for lab, safety or field decisions, always double-check with official protocols. · Privacy Policy · Disclaimer

Print Size Calculator — Pixels to CM/Inches at Any DPI

← Darkroom IsleThe Creative Island · Island 12

How big can I print this? Pixels → cm/inch at any DPI — both directions.

Width (px)

Height (px)

DPI

Reverse: target print width (cm) → pixels needed

How to use this tool

1. Enter your image's pixel dimensions and the print DPI (300 for professional print).
2. Read the maximum print size in cm and inches — with a quality verdict.
3. Or reverse it: enter a target width in cm to learn the pixels you need.

Example

3000 × 2000 px at 300 DPI → 25.4 × 16.9 cm — a crisp A4-ish print. To print 21cm wide at 300 DPI you need 2,480 px — so a 3000px file has room to spare, while an 800px screenshot does not.

The formula

inches = pixels ÷ DPI  |  cm = inches × 2.54  |  pixels = cm ÷ 2.54 × DPI

What the result means

DPI is the density argument of the print, not a property of the file — the same pixels print bigger at 150 DPI and sharper at 300. 300 DPI is the professional standard viewed at arm's length; large posters tolerate 150 because distance forgives softness.

Frequently asked questions

Is 300 DPI always necessary?

For photos and brochures, yes. For billboards, no — viewed from 20 meters, 30 DPI can pass. Match DPI to viewing distance.

My file says 72 DPI — is it bad?

That tag is metadata, not destiny. Change the DPI interpretation and the same pixels print at a different size — which is exactly what this calculator shows.

What size file do I need for an A4 photo print?

A4 is 21 × 29.7 cm; at 300 DPI that's 2480 × 3508 px — about 8.7 megapixels.

Is anything uploaded?

No — pure arithmetic, in your browser.

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• Darkroom Isle — the island where this tool lives.
• The Main Island — drive the boat, explore the whole world.
• The 90s Kids Island — where most of us started.

Privacy & data: this tool runs entirely in your browser — nothing you type is uploaded, saved or sent anywhere. · Disclaimer: your images are opened and processed by your own browser only — files never leave your device, and originals are never modified. · Privacy Policy · Disclaimer

Image Dimension Checker — Size, Ratio & Megapixels

← Darkroom IsleThe Creative Island · Island 12

Drop in any image — see width, height, exact ratio, megapixels and file size at once.

Choose an image

How to use this tool

1. Choose any image from your device.
2. Read the full report: dimensions, simplified ratio, megapixels, format, file size and max print size.
3. The image preview confirms you're inspecting the right file.

Example

A photo reports 4032 × 3024, ratio 4:3, 12.2 MP — the classic smartphone shot. At 300 DPI it prints up to 34 × 26 cm (13×10 inch), and as a full-width web image it is three times wider than needed: resize to 1200px and save the bandwidth.

The formula

ratio = W:W÷gcd(W,H) · megapixels = W × H ÷ 1,000,000 · print cm = pixels ÷ 300 DPI × 2.54

What the result means

The dimension report answers the three questions every image task asks: is it the right shape (ratio), is it big enough for the job (pixels → print size at 300 DPI), and is it heavier than it needs to be (KB per pixel). A 12 MP photo on a webpage is a delivery truck carrying one letter.

Frequently asked questions

What do I check before uploading a form photo?

Two numbers from this report: the pixel dimensions (some forms demand minimums like 132×170) and the KB size (many cap at 20–100KB — the compressor bench handles that).

What counts as 'high resolution'?

For screens, anything at or above the display size is perfect. For print, use the DPI line: 300 DPI is professional print; 150 DPI is usually acceptable for large posters viewed from distance.

Why does my 12MP photo look worse than a 6MP one?

Megapixels measure quantity, not quality — lens, sensor and compression decide quality. Two very different questions.

Is my image uploaded?

No — it's opened locally by your browser; the report is generated on your device.

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• Darkroom Isle — the island where this tool lives.
• The Main Island — drive the boat, explore the whole world.
• The 90s Kids Island — where most of us started.

Privacy & data: this tool runs entirely in your browser — nothing you type is uploaded, saved or sent anywhere. · Disclaimer: your images are opened and processed by your own browser only — files never leave your device, and originals are never modified. · Privacy Policy · Disclaimer

Image Converter — JPG to PNG, PNG to JPG, WebP

← Darkroom IsleThe Creative Island · Island 12

JPG to PNG, PNG to JPG, anything to WebP — converted locally, no upload queues.

Choose an image

Convert to JPG — smallest, photosPNG — lossless, transparencyWebP — modern, smallest of all

Background (for transparent → JPG)

How to use this tool

1. Choose your image (JPG, PNG or WebP in).
2. Pick the target format — and a background color if a transparent PNG is heading to JPG (JPG can't hold transparency).
3. Press Convert & download.

Example

A 1.8 MB PNG screenshot → WebP at 90% quality: typically ~200 KB, pixel-crisp, and supported by every modern browser. A transparent logo PNG → JPG comes out on the white background you chose.

The formula

canvas re-encode: image → canvas → toBlob(target format, quality)

What the result means

Each format has a job: JPG for photographs, PNG for crisp graphics and transparency, WebP for the best of both at 25–35% smaller than JPG. Converting transparent PNG to JPG 'flattens' it onto your chosen background — that's why the color picker exists.

Frequently asked questions

Does converting reduce image quality?

JPG and WebP re-compress at the quality you choose (90 here keeps things visually clean). PNG conversion is lossless — identical pixels, different container.

Can it convert to WebP for my website?

Yes — and you should: WebP cuts 25–35% off JPG sizes with the same look, and every modern browser supports it.

What about HEIC (iPhone) photos?

Modern browsers decode HEIC in file inputs on most platforms; if yours doesn't, export the photo as JPG from your gallery first.

Are my files uploaded?

No — conversion happens entirely in your browser.

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Image CompressorShrink to any KBImage ResizerExact pixels or percentagesImage CropperRatios & passportsImage Dimension CheckerSize, ratio, megapixels

Explore the island world

• Darkroom Isle — the island where this tool lives.
• The Main Island — drive the boat, explore the whole world.
• The 90s Kids Island — where most of us started.

Privacy & data: this tool runs entirely in your browser — nothing you type is uploaded, saved or sent anywhere. · Disclaimer: your images are opened and processed by your own browser only — files never leave your device, and originals are never modified. · Privacy Policy · Disclaimer

Image Cropper — Ratios & Passport Sizes, In-Browser

← Darkroom IsleThe Creative Island · Island 12

Crop to the ratio you need — square for profiles, 16:9 for video, 3.5:4.5 for passports — position it, download it.

Choose an image Crop ratio 1:1 — square / profile 4:5 — portrait post 16:9 — video / cover 3:2 — classic photo Passport 35×45mm (BD/India) 2:2 — US visa 2×2 inch Vertical position: center

How to use this tool

1. Choose your photo — the preview shows the live crop.
2. Pick the ratio: square, portrait, video, or exact passport standards (35×45mm is the Bangladesh/India standard).
3. Slide the vertical position to frame the face where it should be, then download.

Example

Passport applications: select Passport 35×45mm, position the face center-top, download — the file comes out at 413×531px, which prints at exactly 35×45mm at 300 DPI.

The formula

crop window = largest rectangle of the chosen ratio that fits inside the photo, centered horizontally, slider-controlled vertically

What the result means

Cropping to a ratio is what official forms and social platforms actually enforce — they take your square or your 16:9 whether you chose it or not. Doing it yourself means the subject stays framed instead of guillotined. Passport crops come out at 300 DPI-ready pixels, so printing shops get an exact file.

Frequently asked questions

Can I crop to a free size, dragging corners?

This bench crops by fixed ratios — deliberately, because ratios are what forms and platforms demand. Free-form crops belong in a full editor.

Is 35×45mm the right passport size for Bangladesh?

Yes — the standard Bangladesh/India passport photo size (the US uses 2×2 inches instead, also in the list). Always double-check the specific form's instructions before printing.

Does cropping reduce quality?

No — it cuts pixels away, it doesn't stretch them. The remaining area is full original resolution.

Are my photos uploaded?

No — the crop happens on a canvas in your browser and the download is generated locally.

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Image ResizerExact pixels or percentagesImage CompressorShrink to any KBImage Dimension CheckerSize, ratio, megapixelsPrint Size CalculatorPixels to print size

Explore the island world

• Darkroom Isle — the island where this tool lives.
• The Main Island — drive the boat, explore the whole world.
• The 90s Kids Island — where most of us started.

Privacy & data: this tool runs entirely in your browser — nothing you type is uploaded, saved or sent anywhere. · Disclaimer: your images are opened and processed by your own browser only — files never leave your device, and originals are never modified. · Privacy Policy · Disclaimer