Shipping Margin Calculator — True Profit After Fees, Tax and Postage

Work out real profit per order after platform fees, payment processing, tax, packaging and shipping. Price sweeps, break-even solver, bulk SKUs. Runs in your browser.

What it does

The Shipping Margin Calculator shows what you actually keep from an online order. Enter the item price, what you charge for shipping, what the product costs you and what the carrier bills you, and choose how your sales platform and payment provider take their cut. The tool returns net profit, margin, return on landed cost, and a line-by-line breakdown that adds up to the cent.

It goes beyond a single number. It solves for the price you need to break even, hit a target margin or earn a target profit; sweeps a range of prices to show where you start losing money; compares charging for shipping with offering it free; and prices a whole catalog at once from a CSV.

How it works

All money is calculated in whole cents, so the breakdown always reconciles exactly and rounding never leaves a stray penny. Each fee is worked out separately, the way marketplaces charge them:

Platform fee. A percentage plus an optional fixed fee, with switches for whether the percentage applies to shipping and to tax, and an optional cap for platforms that limit the percentage fee per item.
Payment processing. A percentage plus a fixed fee, applied either to the full amount the buyer paid (including tax) or only to items and shipping.
Tax and VAT. Enter tax as extra on top of your price or as already included in it (VAT-style), and choose whether it applies to shipping. Tax is passed through to the tax authority, so it never counts as revenue.
Shipping cost from weight. Enter the parcel’s actual weight and its dimensions. The tool computes volumetric (dimensional) weight using the divisor your carrier uses, bills the larger of the two, optionally rounds it up to the next step, and looks the price up in a rate table you paste in, with optional columns for zones. If you don’t use a table, it uses the manual shipping cost you typed.
Returns. Give a return rate, the return label cost, how much stock you can resell, and whether the platform refunds its percentage fee. The tool blends a normal order and a returned order into an expected profit per order.
Solvers. Break-even, target-margin and target-profit prices are found by searching the exact same calculation used for the breakdown, so the answers respect fee caps, tax settings and rounding. If no price can reach a target because fees grow as fast as the price does, the tool says so instead of returning a nonsense figure.

Fee presets for common marketplaces and card processors are only a starting point. They are approximate, every field is editable, and you should check your own account for current rates. You can save your own fee settings as a named preset.

How to use it

Pick a platform preset, or start from Custom and enter your fees.
Fill in the sale: item price, items per order, shipping charged and tax.
Enter your costs: product cost per item, packaging, and shipping you pay. To have shipping calculated for you, enter weight and dimensions, choose a divisor preset, tick the rate-table option and paste your carrier’s rates.
Read the result card: profit, margin, the breakdown, and the break-even, target-margin and target-profit prices.
Open Price sweep to see profit at every price in a range, Free shipping to compare absorbing shipping with raising the price, and Scenarios to save up to four setups side by side, such as the same product on two platforms.
For a whole catalog, open Bulk SKUs and drop or paste a CSV with a header row. Recognised columns are sku, price, cost, weight, length, width, height, ship_charged and qty. Each row is priced with your current settings, and losing or thin-margin SKUs are flagged.
Export a CSV or a PDF summary, or copy the summary text.

If your supplier sheet is untidy, tidy it first with the CSV cleaner, and combine several price lists into one file with the CSV merger before dropping it into Bulk SKUs. If your weights or dimensions come in mixed units, the unit converter will sort them out. And once you know your per-order profit, the break-even calculator tells you how many orders it takes to cover your fixed costs.

Privacy and saved data

Nothing you enter is uploaded. Your inputs, saved scenarios, custom presets and any CSV you add are remembered in this browser so they’re still there after a refresh, and nowhere else. Use Clear saved data to remove them from a shared computer. The PDF export downloads a small open-source PDF library the first time you use it; none of your data is sent. Exchange rates aren’t fetched from the internet: if you pay suppliers or carriers in another currency, type your own conversion rate.

Limitations

Fee presets are approximate and marketplaces change their fees. Treat them as a starting point.
Carrier surcharges (fuel, residential, oversize) aren’t modelled unless you include them in your rate table or manual shipping cost.
The free-shipping analysis assumes shipping cost changes only by the “extra shipping per added item” you enter.
This is a planning tool, not tax or accounting advice.

FAQ

How do I find the price I need to hit a target margin?

Set Target margin % in the Returns & targets section. The result card shows the lowest price, to the cent, that reaches that margin with your fees, tax and shipping settings. The same card shows your break-even price and the price for a target profit amount.

What is volumetric (dimensional) weight, and why does it matter?

Carriers charge for the larger of a parcel’s actual weight and a weight computed from its size. The formula is length × width × height divided by a carrier-specific divisor. A light but bulky box can therefore be billed as heavy. Enter your dimensions and divisor and the tool shows which weight wins and looks up the price for it.

Should the platform fee apply to shipping and tax?

It depends on the platform, which is why both are switches. Many marketplaces charge their percentage on the item, shipping and tax together, while others exclude some of them. Check your platform’s fee page and set the switches to match.

Does the tool include free shipping?

Yes. The Free shipping tab compares your current setup with the same price and shipping charged at zero, shows the price you’d need to keep the same profit if you offer free shipping, and finds the smallest order size at which free shipping still reaches your target margin.

What CSV format does bulk mode expect?

A header row plus one line per product. The only required column is price. Add cost, weight, length, width, height, ship_charged, qty and sku as needed. Commas or semicolons and prices such as $1,299.50 or 1.299,50 are understood. Rows with invalid values are listed rather than silently skipped.

Are my numbers or files sent to a server?

No. Everything is calculated in your browser, including the PDF and CSV exports, and nothing is uploaded.