WooCommerce Price Calculator – Free Plugin to Calculate Product Prices by Weight, Volume & Dimensions

WooCommerce Price Calculator is essential if you want to sell products based on weight, volume, length, area or custom units instead of simple item quantities. With our free plugin, you can easily create dynamic price calculations in WooCommerce, letting customers buy exactly the amount they need — in kg, liters, square meters, or any custom measurement you set. Build your own WooCommerce price calculator in minutes and start selling products with flexible, measurement-based pricing.

What Is a WooCommerce Price Calculator?

A WooCommerce price calculator is a tool or plugin that automatically calculates a product’s price based on measurement units such as weight, volume, length, area, or dimensions (L×W×H). Instead of selling items per piece, you can let customers enter the exact quantity they need — for example kg of produce, liters of liquid, meters of fabric, or custom cubic measurements — and WooCommerce will calculate the final price dynamically.

A WooCommerce measurement price calculator goes a step further than a simple quantity field — it lets you define entirely custom units of measure that match how your products are actually sold, whether that's kilograms of coffee beans, meters of ribbon, or square meters of tile. Instead of forcing every product into WooCommerce's default "per item" logic, a measurement price calculator recalculates the total price in real time as customers adjust the quantity, so what they see on the product page always matches what they'll pay at checkout.

Why Offer Pricing Based on Weight, Size or Volume?

You need a WooCommerce price calculator if your products cannot be sold as simple “per item” quantities. This applies to businesses that sell by weight (kg, lbs), volume (liters, gallons), length (meters, yards), area (sq ft, sq m), or dimensions (L×W×H). A price calculator helps you:

• provide accurate prices based on measurements
• sell customizable product quantities
• reduce manual calculations
• prevent pricing errors
• automate shipping cost adjustments

A reliable WooCommerce price calculator isn't just about convenience — it directly protects your margins. Manually estimating prices for weight- or volume-based products almost always leads to under- or overcharging, especially when orders combine multiple units or custom quantities. By automating the calculation with Flexible Quantity, every price shown to the customer is exact, consistent, and based on rules you define once — whether you're running a food store selling produce by kg, a fabric shop charging by the meter, or a service business billing by distance or area.

How WooCommerce Price Calculator Works (Default vs Custom Units)

As you know, by default, WooCommerce uses the standard units of measure & dimensions (kg, g, lbs, oz for the weight and m, cm, mm, in, yd for the dimension). You may use those units for setting the weight and dimensions of the product for shipping purposes.

But you can offer products by their quantity (stock) only. Now, what if you'd like to sell based on more units of measure and calculate the price accordingly? Then, you're in the right place!

Today, I'll show you how to sell lemons by weight and lemon juice by volume. You'll learn how to offer products with the new units of measure (weight and volume).

It's worth noting that switching to a measurement-based price calculator doesn't mean giving up WooCommerce's standard inventory tools. Stock levels, low-stock notifications, and backorder settings still work as expected — the plugin simply changes how the quantity a customer selects translates into a price and a stock deduction. This makes the transition low-risk: you can enable a price calculator on a handful of products first, see how it performs, and expand it across your catalog once you're confident it fits your workflow.

WooCommerce Price Calculator — Free Plugin Setup Guide

To calculate product prices based on new units of measure:

1. First, download and install the Flexible Quantity free plugin from the WordPress repository,Flexible Quantity plugin for FREE →
2. Then, go to the product edit screen and enable the new unit of measure (for example, km for transportation services),
   
3. Finally, set the new unit for dynamic price calculations.
   

Letting customers enter smaller units also reduces friction at the point of purchase. Few shoppers think in exact liters or kilograms when buying something like lemon juice or spices — they're far more used to entering values in milliliters or grams. By allowing input in these familiar, smaller units while calculating the final price in the main unit behind the scenes, a WooCommerce price calculator matches the way customers naturally think about quantity, which reduces input errors and makes the buying decision feel more intuitive.

Using WooCommerce Price Calculator for Weight-Based Pricing

Now, you can use weight as a new unit of measurement as well. The plugin lets you define the unit name, prices, increment value, or minimum and maximum unit quantity. Let's see how the plugin helps you build your WooCommerce price calculator for the weight units.

1. The initial steps are similar as shown above: open the product edit screen and enable the new unit of measure,
2. Set kg for our lemons as a new unit of measurement, and choose its parameters,
   
3. Finally, see our lemons sold per kg in your WooCommerce store.
   

As you see, WooCommerce will show the final price per kg based on the dynamic price calculations.

Weight-based pricing is particularly common in grocery, garden, and building-material stores, where the cost of goods themselves scales directly with weight. A WooCommerce price calculator removes the need to pre-package products into fixed weight tiers just to keep pricing simple — customers can order 1.3 kg of lemons instead of being forced to round up to a 2 kg bag, which usually means less food waste for the seller and a fairer price for the buyer.

How to Let Customers Buy Products by Volume Online

Let's see now how to sell lemon juice by volume.

1. First, add a new WooCommerce product and enable the new unit of measure (liters),
2. Set the new unit and its parameters,
   
3. That's it! We've just added lemon juice to the store's shelves.
   

Moreover, there are additional options for inventory below the unit settings. You can decide that the new unit will change the product stock based on the quantity (e.g. kg, or l). You may also allow customers to buy one product only, for example, 3 kg of lemons, without the option to select more 3kg "bags".

The above options are included in the Flexible Quantity - Measurement Price Calculator for WooCommerce free plugin.

WooCommerce Price Calculator PRO — Calculate Price from Smaller Units (ml, g)

There is a way to sell lemons per kilograms or liters, but also let customers enter the smaller units (here grams and milliliters) to calculate the unit quantity and the product prices.

Let's suppose you want to sell lemon juice: for $7 per liter, but let your clients enter the volume every 100 ml up to 10000 ml (10 liters).

To set that option for your WooCommerce product with the price calculator plugin:

1. Enable the unit dimensions,
   
2. Choose the dimension's properties (the ml as a smaller unit of measure, the increment, the unit label, and minimum and maximum values too),
   
3. Done! Your customers can now enter the volume in milliliters. The plugin will calculate the price in full liters dynamically.
   

Advanced WooCommerce Price Calculator Options — Dynamic Pricing & Shipping Tables

Sometimes you may want the product price to depend on the quantity of the new unit of measure. The plugin gives you 2 options: the pricing table and the shipping class table.

Beyond simple per-unit pricing, a well-configured WooCommerce price calculator can adapt to how your customers actually buy. For example, a bulk buyer purchasing 20 kg of lemons might qualify for a lower per-kg rate than someone ordering just 1 kg — and with the pricing table, you can set those quantity-based tiers without creating separate products or variations for each range. This keeps your product catalog clean while still rewarding larger orders, which is especially useful for wholesale, B2B, or farm-to-table stores where order sizes vary widely from one customer to the next.

Shipping costs are one of the most overlooked parts of measurement-based selling, but they matter just as much as the product price itself. A store selling fabric by the meter or produce by the kilogram often faces shipping costs that scale directly with quantity — a 1 kg order and a 20 kg order simply cost different amounts to ship. With the shipping class table, you can tie shipping rates to the same measurement unit used for pricing, so customers always see accurate delivery costs upfront instead of a flat rate that under- or overcharges depending on how much they order.

Price calculator based WooCommerce product quantity

The pricing table lets you set the ranges for different prices and sale prices based on the quantity.

The product price will now depend on the product quantity (based on your new unit of measurement).

Flexible shipping costs depend on the unit quantity

You can also enable and set the shipping class table. Choose the quantity ranges and choose the shipping classes.

The shipping cost will depend on the quantity of the new unit of measure of your WooCommerce product.

That will give you flexible shipping costs in your WooCommerce store based on the product quantity (and the new unit of measure).

Summary

In this article, you've learned how to use a free measurement price calculator for WooCommerce to sell products based on new units of measure. I've shown you weight and volume-based products with prices based on the new units. Also, how to use the pricing table and shipping class table for dynamic prices of new products with the PRO version of the plugin.

Visit Flexible Quantity - Measurement Price Calculator for WooCommerce PRO to see all features, check the plugin documentation, and run your tests in a free demo!

If you have more questions, just let us know!

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