Whether you are new to refillable vapes or already comfortable mixing shortfills, an e-liquid calculator is one of the most useful tools you can use. Getting your numbers wrong can waste liquid, weaken the flavour, make the nicotine strength inaccurate, or leave you with a vape juice that does not suit your device.

This guide explains how an e liquid mixing calculator works, how to calculate nicotine in e liquid, how PG/VG ratios affect your vape, and how to mix more accurately without making the common mistakes many vapers make.

This guide is for adult vapers only. Nicotine products should always be handled carefully and kept away from children and pets.

What Is an E-Liquid Calculator and Why Do You Need One?

An e-liquid calculator is a tool that helps you work out the correct amount of each ingredient in your finished vape juice. Instead of guessing how much nicotine shot, VG, PG, or flavour concentrate to add, you enter your target details and the calculator gives you accurate measurements.

Most e-liquid calculators ask for:

• Final bottle size
• Target nicotine strength
• Nicotine shot strength
• PG/VG ratio
• Flavour percentage
• Current liquid volume
• Number of nicotine shots added

A good e liquid calculator helps you keep every mix consistent. This is useful when you find a flavour and strength you like and want to repeat it again without changing the result.

Understanding E-Liquid Ingredients Before You Mix

Before using an e liquid mixing calculator, it helps to understand the main ingredients in vape juice.

Propylene Glycol, Also Called PG

PG is a thinner base liquid. It carries flavour well and gives more throat hit. Many flavour concentrates and some nicotine shots contain PG, so it can affect the final PG/VG ratio of your mix.

If you use a pod kit or mouth-to-lung device, a balanced PG/VG ratio such as 50/50 is often easier for the coil to absorb.

Vegetable Glycerine, Also Called VG

VG is thicker than PG and helps create more vapour. High-VG e-liquids are usually smoother and better suited to sub-ohm vape kits.

The downside is that very thick liquid may not work well in small pod kits or low-powered devices. If the liquid is too thick for the coil, you may get dry hits, weak flavour, or faster coil wear.

Nicotine Shots

Nicotine shots are commonly used to add nicotine to shortfill e-liquids. In the UK, nicotine-containing e-liquids sold to consumers are limited to a maximum strength of 20mg/ml, and nicotine refill containers are limited to 10ml.

Common nic shot strengths include:

• 18mg/ml nicotine shots
• 20mg/ml nicotine shots

Shortfills are usually sold without nicotine and leave space in the bottle for nicotine shots. For example, a 50ml shortfill bottle often has enough space for one 10ml nic shot.

Flavour Concentrates

Flavour concentrates give e-liquid its taste. They are strong and should be measured carefully. More flavour does not always mean better flavour. Too much concentrate can make the liquid harsh, overly sweet, chemical-tasting, or muted.

Most flavour concentrates are used between 5% and 20%, depending on the flavour type and brand recommendation.

UK Rules Vapers Should Know Before Mixing

For UK vapers, it is important to follow current vape product rules when buying and using nicotine products.

The main points are:

• Nicotine-containing e-liquid sold to consumers must not exceed 20mg/ml.
• Nicotine refill containers are limited to 10ml.
• Nicotine products should be child-resistant and tamper-evident.
• E-liquids should only be purchased from reputable vape retailers.
• Do not use ingredients that are not made for vaping.
• Keep nicotine products away from children, pets, heat, and direct sunlight.

This matters because online DIY advice from other countries may mention high-strength nicotine bases that are not suitable for normal UK consumer mixing. For UK vapers, shortfills and compliant nic shots are the safer and more practical route.

How to Calculate Nicotine in E Liquid: Simple Formula

This is the part many vapers search for first: how to calculate nicotine in e liquid.

The simple formula is:

Final nicotine strength = total nicotine amount ÷ final liquid volume

To find the total nicotine amount:

Nicotine shot strength × amount of nicotine shot added

Example 1: 50ml Shortfill With One 18mg Nic Shot

You have:

• 50ml nicotine-free shortfill
• 1 x 10ml nicotine shot at 18mg/ml
• Final bottle volume: 60ml

Calculation:

18mg × 10ml = 180mg total nicotine

180mg ÷ 60ml = 3mg/ml

So, a 50ml shortfill plus one 10ml 18mg nic shot gives around 3mg e-liquid.

Example 2: 100ml Shortfill With Two 18mg Nic Shots

You have:

• 100ml nicotine-free shortfill
• 2 x 10ml nicotine shots at 18mg/ml
• Final bottle volume: 120ml

Calculation:

18mg × 20ml = 360mg total nicotine

360mg ÷ 120ml = 3mg/ml

So, a 100ml shortfill plus two 10ml 18mg nic shots gives around 3mg e-liquid.

Example 3: 50ml Shortfill With One 20mg Nic Shot

You have:

• 50ml nicotine-free shortfill
• 1 x 10ml nicotine shot at 20mg/ml
• Final bottle volume: 60ml

Calculation:

20mg × 10ml = 200mg total nicotine

200mg ÷ 60ml = 3.33mg/ml

So, a 50ml shortfill plus one 10ml 20mg nic shot gives around 3.3mg e-liquid.

Shortfill Nicotine Calculator Formula

Use this formula if you want to calculate how much nic shot you need:

Nic shot amount = target strength × shortfill volume ÷ nicotine shot strength minus target strength

Example:

You have 50ml nicotine-free shortfill and want 3mg strength using an 18mg nic shot.

3 × 50 ÷ 18 - 3

150 ÷ 15 = 10ml

So, you need 10ml of 18mg nicotine shot.

This is why many 50ml shortfills are designed to take one 10ml nic shot.

Quick Shortfill Nicotine Calculator Chart

Shortfill Liquid

Nic Shot Used

Final Volume

Approx Final Strength

50ml shortfill

1 x 10ml 18mg shot

60ml

3mg

100ml shortfill

2 x 10ml 18mg shots

120ml

3mg

50ml shortfill

1 x 10ml 20mg shot

60ml

3.3mg

100ml shortfill

2 x 10ml 20mg shots

120ml

3.3mg

40ml shortfill

1 x 10ml 18mg shot

50ml

3.6mg

This chart is useful for common shortfill setups. However, an e-liquid calculator is still better if your bottle size, nicotine shot strength, or target nicotine level is different.

How to Use an E-Liquid Mixing Calculator: Beginner Walkthrough

Using an e liquid mixing calculator is simple once you know the numbers you need.

Step 1: Set Your Final Bottle Size

Choose how much finished e-liquid you want. If you are testing a new flavour, start small. A 30ml or 50ml test bottle is better than wasting a large batch.

Step 2: Enter Your Target Nicotine Strength

This is the final nicotine strength you want after mixing. Common strengths include:

• 0mg
• 3mg
• 6mg
• 10mg
• 12mg
• 18mg
• 20mg

Lower nicotine strengths are often used in sub-ohm kits. Higher nicotine strengths are more common in pod kits and mouth-to-lung devices.

Step 3: Enter Your Nicotine Shot Strength

Check the label on your nic shot. Most UK nic shots are 18mg/ml or 20mg/ml.

Do not guess this number. The nicotine strength of the shot directly changes the final result.

Step 4: Set Your PG/VG Ratio

Choose the ratio that suits your device. For example:

• 50/50 for pod kits and MTL devices
• 60VG/40PG for balanced smoothness and flavour
• 70VG/30PG for sub-ohm vaping
• 80VG/20PG for thicker liquid and bigger vapour

Step 5: Add Your Flavour Percentage

Enter the flavour concentrate percentage. If you are using a one-shot concentrate, follow the recommended mixing percentage on the bottle.

Step 6: Calculate and Measure

The calculator will show how much of each ingredient to use. Measure carefully, shake well, label the bottle, and allow steeping time if needed.

PG/VG Ratio Guide: Which One Should You Choose?

Ratio

Throat Hit

Vapour Production

Best For

50PG/50VG

Medium

Medium

Pod kits, MTL devices

40PG/60VG

Medium

Medium to high

Balanced vaping

30PG/70VG

Low to medium

High

Sub-ohm tanks

20PG/80VG

Low

Very high

High-powered devices

Max VG

Minimal

Maximum

Advanced cloud setups

The right ratio depends on your vape kit. A high-VG liquid may not wick properly in a small pod kit, while a thin 50/50 liquid may feel too sharp in a powerful sub-ohm tank.

Flavour Concentrate Percentages: Quick Reference

Flavour Type

Typical Usage Rate

Light fruit flavours

5% to 10%

Strong fruit blends

10% to 15%

Menthol and mint

3% to 8%

Dessert and bakery

10% to 18%

Custard and cream

12% to 20%

Tobacco flavours

5% to 15%

One-shot concentrates

Follow brand guidance

These are starting points, not fixed rules. Always test a small batch first. Some concentrates are strong at 5%, while others need more time and a higher percentage to develop.

Mixing by Weight vs Mixing by Volume

Most beginners measure e-liquid by volume using syringes, pipettes, or bottle markings. This can work, but it is not always the most accurate method.

Mixing by weight uses a digital scale. Many experienced mixers prefer this because it is cleaner, faster, and more consistent.

Why Weight-Based Mixing Can Be Better

• Less mess than syringes
• Better accuracy for thicker VG
• Easier for larger batches
• More repeatable results
• No air bubbles affecting measurements

VG is thicker and heavier than PG, so weight-based calculators use ingredient density to give better measurements. If your e liquid mixing calculator has a weight mode, it can be useful once you understand the basics.

Common E-Liquid Mixing Mistakes and How to Avoid Them

Mistake 1: Not Checking Final Bottle Volume

If you add a 10ml nic shot to 50ml shortfill, the final volume is 60ml, not 50ml. Your nicotine calculation must be based on the finished bottle volume.

Mistake 2: Forgetting That Flavour Concentrates Affect PG/VG Ratio

Many flavour concentrates are PG-based. If you add 15% flavour, you are also adding PG to your final mix. This can change the final ratio.

Mistake 3: Adding Too Much Flavour

Over-flavouring is one of the most common mistakes. It can make the vape harsh, too sweet, or dull. Start low and increase slowly if needed.

Mistake 4: Not Allowing Steeping Time

Some liquids taste better after resting. Fruit and menthol flavours may be ready quickly, but desserts, custards, creams, and tobacco blends often need longer.

Mistake 5: Not Labelling Your Bottles

Always label your bottle with:

• Flavour name
• Nicotine strength
• PG/VG ratio
• Mix date
• Flavour percentage

This helps you repeat good mixes and avoid confusion later.

Mistake 6: Poor Nicotine Safety

Nicotine should be handled carefully. Avoid skin contact, close bottles tightly, and keep all vape liquids away from children and pets.

Steeping Your E-Liquid: Does It Really Matter?

Yes, steeping can make a big difference. Steeping means letting your e-liquid rest so the flavour becomes smoother and more balanced.

Simple Steeping Guide

Flavour Type

Suggested Steeping Time

Fruit flavours

1 to 3 days

Menthol flavours

Usually ready quickly

Candy flavours

3 to 7 days

Dessert flavours

1 to 2 weeks

Custard and cream

2 to 4 weeks

Tobacco flavours

1 to 3 weeks

Shake the bottle well after mixing. Store it in a cool, dark place. Do not leave e-liquid in direct sunlight, near heat, or inside a hot car.

E-Liquid Calculator Example: Full Manual Mix

Let’s say you want to make 100ml of e-liquid with:

• 3mg nicotine strength
• 70VG/30PG ratio
• 15% flavour concentrate
• 18mg nicotine shot

First, calculate the nicotine:

3mg × 100ml = 300mg total nicotine needed

300mg ÷ 18mg = 16.7ml nicotine shot

So, you need around 16.7ml of 18mg nicotine shot.

Next, calculate the flavour:

100ml × 15% = 15ml flavour concentrate

Now the calculator helps adjust the remaining VG and PG based on whether your nic shot and flavour concentrate are VG-based or PG-based.

This is where an e-liquid mixing calculator becomes very useful because it handles the smaller details that are easy to miss manually.

Choosing the Right Nicotine Strength for Your Device

The right nicotine strength depends on how you vape and what device you use.

Vaper Type

Common Nicotine Strength

Sub-ohm vaper

3mg to 6mg

Light smoker switching to vaping

3mg to 6mg

Medium smoker switching to vaping

6mg to 12mg

Heavy smoker switching to vaping

12mg to 20mg

Pod kit or MTL vaper

10mg to 20mg

High-powered devices produce more vapour per puff, so lower nicotine strengths are usually more comfortable. Low-powered pod kits produce less vapour, so higher strengths are often used by adult smokers switching from cigarettes.

Is an E-Liquid Calculator Better Than Guessing?

Yes. Guessing can lead to weak nicotine, harsh liquid, poor flavour, incorrect VG/PG balance, or wasted ingredients.

An e-liquid calculator gives you:

• Better nicotine accuracy
• More consistent flavour
• Better PG/VG control
• Less wasted liquid
• Easier recipe testing
• More repeatable results

For shortfill users, it helps confirm final nicotine strength. For DIY mixers, it is essential because every ingredient affects the final result.

Important Safety Tips for Adult Vapers

Before mixing or adjusting any e-liquid, follow these safety steps:

• Only buy vape ingredients from trusted retailers.
• Do not use oils, food syrups, essential oils, or random flavourings.
• Do not mix near children or pets.
• Wear gloves if handling nicotine shots.
• Wash skin immediately if nicotine liquid spills.
• Store bottles upright in a cool, dark place.
• Do not vape a liquid if it smells unusual, separates badly, or looks contaminated.

Vape juice should be treated carefully. Accurate mixing is not only about flavour. It is also about responsible nicotine handling.

Final Word: Mix Smarter, Not Harder

An e-liquid calculator removes guesswork and helps you mix with more control. Whether you are topping up a shortfill, adjusting nicotine strength, testing a new flavour, or working out a PG/VG ratio, getting the numbers right makes a major difference.

Start with a small batch. Use a reliable calculator. Write down every mix. Let the liquid steep when needed. Most importantly, do not guess your nicotine strength.

That is how better e-liquid is made.

Looking for shortfills, nic shots, and vape essentials? Explore the full range at VapeKitUK.

FAQs: Vapers Ask About E-Liquid Calculators

1. What is the easiest way to calculate nicotine in e-liquid?

The easiest way is to multiply the nicotine shot strength by the amount added, then divide it by the final bottle volume.

Example:

18mg × 10ml = 180mg total nicotine

180mg ÷ 60ml = 3mg/ml

So, one 10ml 18mg nic shot added to 50ml shortfill gives around 3mg e-liquid.

2. How many nic shots do I need for a 100ml shortfill?

Most 100ml shortfills need two 10ml 18mg nicotine shots to make around 3mg finished e-liquid. This gives a final volume of 120ml.

If you use 20mg nic shots instead, the final strength will be around 3.3mg.

3. Can I make 6mg e-liquid from a shortfill?

Yes, but it depends on bottle space, nic shot strength, and final volume. A standard 50ml shortfill with one 10ml 18mg nic shot usually makes around 3mg. To reach 6mg, you need more nicotine, which may require a different bottle size or a different mixing method.

Always use an e-liquid calculator before trying to increase nicotine strength.

4. What PG/VG ratio should I use?

For pod kits and mouth-to-lung vaping, 50/50 is usually a good choice. For sub-ohm vaping, 70VG/30PG is more common because it creates more vapour and feels smoother.

Use the ratio that suits your device, not just the ratio that sounds popular.

5. Why does my e-liquid taste weak after mixing?

Your e-liquid may taste weak because the flavour percentage is too low, the mix needs steeping, your coil is old, or the PG/VG ratio does not suit your device. Before adding more flavour, let the bottle rest and test it again with a fresh coil.

6. Is DIY e-liquid mixing cheaper?

DIY mixing can be cheaper for experienced adult vapers, but only when done correctly. You need accurate measurements, safe nicotine handling, proper storage, and a clear understanding of nicotine strength, PG, VG, and flavour percentages.