--- title: "UK parcel shipping cost calculator in kg and cm | AumnI tools" description: "Enter a box in centimetres and kilograms to get its billable weight at divisor 5000, compare rates you type in, add cover and estimate import duty and VAT in pounds." url: https://aumnitools.com/uk/tool/shipping-cost-calculator category: "Lifestyle" country: "United Kingdom" updated: 2026-11-08 --- # Shipping Cost Calculator A UK parcel is measured in centimetres and kilograms, and the courier bills whichever is larger: the scale weight or the box volume divided by a divisor. This page opens in metric with divisor 5000, prices the parcel against rates you enter in pounds, and can add an import duty and VAT estimate at the 20% standard rate. ## United Kingdom rules and figures - On the GOV.UK VAT rates page, the standard rate is 20%, reduced goods carry 5% and zero-rated goods carry 0%. The VAT box on the customs tab fills in 20 for you. - Parcels in the UK settings are measured in kilograms and centimetres, which is why this version starts in metric at divisor 5000 and not in inches and pounds. - Goods value, threshold and duty on the customs tab are sample entries you can overwrite. None of them is an HMRC figure. Sources: [GOV.UK: VAT rates](https://www.gov.uk/vat-rates) (checked 2026-11-08) ## How the shipping cost calculator works Volume in cubic centimetres is divided by the divisor to give dimensional weight in kilograms. The larger of that and the scale weight is billable, and each service charges its per-kilogram rate on it, plus a fee per parcel and a surcharge. Formula: `dimensional kg = L × W × H ÷ 5000; billable = max(actual, dimensional); price = (billable × rate + fee × parcels) × (1 + surcharge %) + cover` - The divisor menu offers 5000, 6000 and 4000 for centimetres and kilograms. 5000 is selected to begin with, and a smaller number charges more for light, bulky boxes. - The Economy, Standard and Express rows are illustrative: £2.20, £3.40 and £7.80 per kilogram, with parcel fees and surcharges beside them. They are not any courier's prices, so overwrite them with a real quote. - Billable weight is exact to the gram and is not rounded up to a courier's next band. There are no zones or minimum charges. - The length-plus-girth figure for each box is shown and flagged above 330 cm, but it never changes a price. - On the Customs tab, duty applies only when the goods value is above the threshold you type, and VAT is charged on goods plus the cheapest shipping plus duty. The VAT box starts at 20 and all three inputs can be changed. ## How to use the shipping cost calculator 1. **Check the units and divisor.** The page starts in centimetres and kilograms with divisor 5000. Change either if your courier's terms say otherwise. 2. **Describe the parcel.** Enter length, width, height and weight, and a count if you are sending several identical boxes. 3. **Type in the rates you were quoted.** Replace the three illustrative rows with the courier's rate per kilogram, the fee per parcel and any surcharge. 4. **Add cover for the goods.** Switch insurance on and enter its percentage and the value to cover. The amount is added to each service. 5. **Estimate import charges.** For a parcel arriving from abroad, turn the border switch on and type the goods value, a threshold, the duty rate and the VAT rate. 6. **Copy or export the quote.** Use Copy for a short text quote you can paste into an email, or Export for a CSV file that lists the boxes and the services. ## Example: Posting 4 kg in a 50 × 35 × 20 cm carton Multiplying the sides gives 35,000 cm³. Divide by 5000 and the carton counts as 7.00 kg, which beats the 4.00 kg shown on the scale, so 3.00 kg of the charge is air. Using the illustrative rates, Economy costs £22.29, Standard £33.97 and Express £78.59. Now suppose the contents are worth £200 and arrive from abroad, with a threshold typed as £150: duty at 4% is £8.00, VAT at 20% is £46.06 on a base of £230.29, and the landed price using Economy is £276.35. ## When to use the shipping cost calculator - **Seeing if a smaller carton saves money.** When dimensional weight is higher than scale weight, the box card says you are paying for air and by how many kilograms. - **Setting two quotes side by side.** Enter each courier's rate, fee and surcharge, and the services list cheapest first with a price per kilogram. - **Working out what a delivery from abroad will cost.** Type the goods value and duty to see the VAT and the total landed cost in pounds. - **Pricing an order of several cartons.** Add a card per box size and the totals add up scale, dimensional and billable weight. ## What the shipping cost calculator does not do - The rates are placeholders typed into a table. Nothing is fetched from Royal Mail or any courier, so use a real quote before relying on a total. - There are no zones, weight bands, residential charges or minimum prices. - Cover is a single percentage of the declared value, and it lands on each service after the surcharge has been applied. - Duty uses a single rate for the whole parcel, although real duty depends on the commodity code. - Courier handling fees for clearing a parcel are not included in the landed cost. - There is one currency symbol and no exchange conversion. ## When something else is a better fit - **When you need a price you can actually book**, use the courier's own quote page, then type its figures in here. - **When you need to convert box sizes to other units**, use the [Unit Converter](https://aumnitools.com/tool/unit-converter.md). ## Questions about the shipping cost calculator ### Why does a light box bill at more than its weight? Its volume decides the charge. A 35,000 cm³ box at divisor 5000 is 7.00 kg dimensional against 4.00 kg on the scale, so 7.00 kg is billed. ### Which divisor should I pick? Whatever your courier's terms state. The 35,000 cm³ carton is 8.75 kg at 4000, 7.00 kg at 5000 and 5.83 kg at 6000, so a different divisor can change what you pay by a few kilograms. ### Are the starting rates real? No. They are illustrative, so Economy at £2.20 a kilogram is just a starting figure. Replace every number with your courier's own. ### Why is VAT higher than 20% of the goods? Import VAT here is charged on goods plus the cheapest shipping plus duty. On £200 of goods the VAT base is £230.29 and VAT is £46.06, against £40.00 on the goods alone. ### What happens at exactly the threshold? Nothing is charged. The charges apply only when the goods value is greater than the threshold, so £150.00 against a £150 threshold pays none and £150.01 pays on the whole value. ## Related tools - [Unit Converter](https://aumnitools.com/tool/unit-converter.md): Converts 102 units in 11 categories, with temperature offsets and 0 to 12 decimals - [Invoice Generator](https://aumnitools.com/tool/invoice-generator.md): Build an invoice with line items, tax and discount, then export it as a PDF file. - [Profit Margin Calculator](https://aumnitools.com/tool/profit-margin-calculator.md): Calculates gross, operating and net profit margins and markup from revenue and costs ## About this page Runs in your browser: what you enter is processed on this device and is not uploaded. Last checked against the tool's code on 2026-11-08. Interactive version: https://aumnitools.com/uk/tool/shipping-cost-calculator