Percent Dilution Calculator: % w/v, v/v, w/w Solutions

Percent Dilution Calculator

Work out how much stock solution and how much water to combine when you dilute a percent concentration. Handles % w/v, % v/v, and % w/w, plus dilution factor, ratio, and grams of solute using C1V1 = C2V2.

🧪Real Dilution Presets

📝Dilution Inputs

What do you want to solve for?

Choose whether the final volume is fixed or you are mixing a known stock volume with water.

Percent concentration type

Stock concentration (%)

The stronger solution you start from.

Target concentration (%)

The weaker solution you want to make. Must be below the stock.

Final volume needed

Total finished volume. Used in stock and diluent modes.

Known stock volume (for mix mode)

Only used when solving for final concentration.

Volume unit

Result rounding

Stock solution needed 0 volume of stock (V1)

Diluent to add 0 water or solvent

Dilution factor 0× stock ÷ target

Solute in final 0 mass or volume of active

🔢Formula Snapshot

C1Stock percent

V1Stock volume

C2Target percent

V2Final volume

📊Dilution Factor Reference

Stock %	Target %	Factor	Ratio (Stock:Diluent)	Per 100 mL Final
100%	50%	2×	1 : 1	50 mL stock + 50 mL water
70%	10%	7×	1 : 6	14.3 mL stock + 85.7 mL water
30%	6%	5×	1 : 4	20 mL stock + 80 mL water
10%	1%	10×	1 : 9	10 mL stock + 90 mL water
8.25%	1%	8.25×	1 : 7.25	12.1 mL stock + 87.9 mL water
5%	0.5%	10×	1 : 9	10 mL stock + 90 mL water
25%	5%	5×	1 : 4	20 mL stock + 80 mL water

🔗Percent to Ratio Conversion

Percent	Fraction	Dilution Ratio	Factor	1 mL Stock Makes
50%	1/2	1:2	2×	2 mL final
25%	1/4	1:4	4×	4 mL final
20%	1/5	1:5	5×	5 mL final
10%	1/10	1:10	10×	10 mL final
5%	1/20	1:20	20×	20 mL final
2%	1/50	1:50	50×	50 mL final
1%	1/100	1:100	100×	100 mL final
0.5%	1/200	1:200	200×	200 mL final

The ratio 1:N here means one part of a 100% source diluted to N parts total. When diluting an already-weaker stock, use the stock ÷ target factor from the calculator instead.

🧴Common Dilution Recipes

Recipe	Stock %	Target %	Type	Per 1 L Final
Disinfecting bleach	8.25%	0.1%	% v/v	12 mL bleach + 988 mL water
Sanitizing bleach	8.25%	1%	% v/v	121 mL bleach + 879 mL water
Hand rub alcohol	99%	70%	% v/v	707 mL alcohol + 293 mL water
Surface alcohol	91%	70%	% v/v	769 mL alcohol + 231 mL water
Saline rinse	10%	0.9%	% w/v	90 mL stock + 910 mL water
Peroxide wound	30%	3%	% v/v	100 mL stock + 900 mL water
Cleaning concentrate	25%	2.5%	% v/v	100 mL stock + 900 mL water

Always add the concentrate to the water, not the other way around, and confirm the label percent before mixing anything for disinfection.

⚖w/v vs v/v vs w/w Reference

Type	Means	1% Equals	Solute	Best For	Example
% w/v	Weight in volume	1 g / 100 mL	Solid in liquid	Salts, sugars, powders	0.9% saline
% v/v	Volume in volume	1 mL / 100 mL	Liquid in liquid	Alcohols, acids	70% ethanol
% w/w	Weight in weight	1 g / 100 g	Mass in mass	Creams, alloys	3% peroxide w/w
% w/v dilute	Keep g fixed	Same g, more mL	Solid stays	Buffer prep	10% to 1% w/v
% v/v dilute	Add solvent	Same mL active	Liquid stays	Alcohol prep	99% to 70% v/v
% w/w dilute	Add by mass	Same g, more g	Weigh diluent	Powder blends	50% to 10% w/w

For w/w work the same C1V1 = C2V2 logic applies, but you weigh the diluent in grams instead of measuring milliliters.

⚙Full Formula Breakdown

Core equationC1 × V1 = C2 × V2. The amount of active ingredient is conserved before and after adding diluent.

Stock volume V1V1 = (C2 × V2) / C1 = (target% × final volume) / stock%. This is how much concentrate to measure out.

Diluent to addWater = V2 – V1 = final volume minus stock volume. It must be zero or positive.

Dilution factorDF = C1 / C2 = stock% / target%. A factor of 10 means the stock is diluted ten-fold.

Parts ratioStock : diluent = 1 : (C1 / C2 – 1). At 70% to 10% that is 1 part stock to 6 parts water.

Grams of solute (w/v)For % w/v, grams in final = target% / 100 × final volume in mL, since 1% w/v is 1 g per 100 mL.

Impossible dilutionIf the target percent is higher than the stock, no amount of water helps. You would need a stronger source.

Final concentration modeMixing a known stock volume V1 into total V2 gives C2 = C1 × V1 / V2.

📋Reference Values

Item	Common Range	How It Is Used	Notes
Stock percent (C1)	5% to 100%	Divides into target × volume	Read from the concentrate label
Target percent (C2)	0.1% to 50%	Sets the working strength	Must stay below the stock
Final volume (V2)	10 mL to 20 L	Total finished batch	Choose the size you will store
Stock volume (V1)	Calculated	Measured from concentrate	Add this to the diluent
Diluent	Calculated	Water or solvent to add	Equals final minus stock volume

💡Practical Dilution Tips

Order tip: Measure the calculated stock volume first, then top up to the final mark with diluent. Adding concentrate to water keeps mixing gentle and the final percent accurate.

Type tip: The math is identical for w/v, v/v, and w/w, but the units differ. Use grams per 100 mL for w/v, mL per 100 mL for v/v, and grams per 100 g for w/w.

The recipe say to use seventy percent alcohol, and you’ve got a bottle labeled ninety-five percent. Half a cup of each doesn’t cut it; percentage is a relative measure but the volume of liquid are absolute.

To dilute something correctly, it’s less about arithmetic and more about tracking what stay constant while everything else change. Whether you begin with a concentrated batch of stock syrup or bleach, the pure active ingredient in there will be the same amount. Adding a solvent such as water stretch that amount over a greater volume. Most people struggle to visualize how much concentrate goes into how much finished product. They also struggle to know how to avoid making too little or wasting extra ingredient.

How to Dilute Correctly

Without all the jargon, it’s actualy a pretty simple equation: Target concentration x Final Total Volume = Concentration of Starting Material x Volume of Starting Material. It doesn’t matter if it’s weight/weight or volume/volume, or even weight/volume; the same relationship hold. And beauty of calculator is that it does the algebra for you, allowing you to get precise measurements while understanding why those inputs matter. But knowing why they go in help avoid expensive errors in the kitchen (or the lab).

Selecting which kind of concentration you’re working with tells it how to evaluate relationship between mass and density. If you use a volume-based recipe for one ingredient but measure it by weight, you will get something other than what you expect when it come time to bake (in this case, flour:water). The ratio won’t be correct and the bread won’t taste right.

Here’s where people go wrong: they mistake the dilution factor for volume of liquid to be added. That number doesn’t tell you how much water to add; the factor indicates simply how many times more diluted (or less concentrated) the resulting solution will be compared to original concentration. To determine exact volume required to bridge the gap from what you have to what you want, you must know just how many solute molecules remain intact. For instance, if I’m taking a ten percent stock and making it into a one percent, then my factor is ten; that means one part of that stock need nine parts of water to reach desired strength.

It works because it keeps the active ingredient intact. That is also why, when laid out in this chart with common household chemicals, we see that most cleaning solution use precise small amounts of concentrated chemical instead of a generous glug.

Consider wound care and contact lens solutions. How hard could it be? You put salt into water, right? Wrong. Precision is important. How hard could it be? You put salt into water, right? Wrong. Precision is important. Osmotic pressure fluctuations affect your body quite strongly, so a few percent difference between what you intended and actualy made will really sting.

That’s where this thing comes in; it computes the exact number of grams of solute to use, given target volume of final product. No more eyeballing things when doubling or tripling a recipe. The mixing ratio stay the same whether you are working with 5 liters or 50 milliliters (a large task versus a small experiment). The only thing that change is how much you has to measure.

The math is one part, but actually doing it correctly is another. If you’re worried about safety (and you should be), then use common sense: add the concentrate to the water; don’t pour water onto concentrated acids/bases. For weak ones such as bleach/alcohol, order doesn’t matter much except for how well they mix. To ensure a good mix, swirl gently, you want everything distributed evenly without generating too much foam which can mess up your volume measurement. Many folks get in a hurry here and end up with a poorly mixed solution in which the bottom of the bottle have a different concentration than what’s in the rest of the mixture.

Before closing the lid, double check numbers. It sounds trivial but it makes a huge difference when you need consistent results each time.

All this leads back to one point: dilution is a balancing act. Start strong; add water; use it. Your focus make it right, while the numbers tell your fingers where to go. You should of used more care with measurement. What are those numbers? They’re what lets you know that there’s as much of the initial goodness left in the end. It doesn’t matter if you are making a scientific reagent or cleaning a countertop. The idea is the same: start strong, add nothing, and end with exactly what you need.