Calculate pre-tax price from total
Recover the price before tax from a total that already includes it: 107.25 at a 7.25% rate splits into 100 before tax and 7.25 of tax, found by dividing by 1.0725. Free in your browser.
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Worked example
- Total price
- 107.25
- Tax rate
- 7.25
- Pre tax price
- 100
- Tax amount
- 7.25
Calculate the pre-tax price when a receipt, invoice, or advertised amount already includes sales tax. Provide the total price and the known tax rate as a percentage, and the calculator separates the gross total into its original pre-tax price and embedded tax amount. It is useful when reconciling receipts, preparing accounting entries, checking tax-inclusive quotations, or testing checkout software.
How to calculate the pre-tax price from a total
A tax-inclusive total is not separated by simply subtracting the tax rate from the final amount. Sales tax was calculated from the original pre-tax price, so the correct operation reverses the multiplier used when tax was added. The calculator converts the percentage rate into a decimal, adds one, and divides the total price by that factor.
For example, a total of 107.25 at a rate of 7.25 percent has a factor of 1.0725. Dividing 107.25 by 1.0725 gives a pre-tax price of 100, and subtracting 100 from the total gives a tax amount of 7.25. Enter 7.25 for a rate of 7.25 percent, not 0.0725.
The calculator accepts a zero rate, which leaves a positive total entirely pre-tax and returns zero tax.
Supplying valid totals and rates
Remove currency symbols, grouping commas, and explanatory text before submitting a value. The total must be greater than zero because the requested breakdown must produce a positive pre-tax price. The tax rate may be zero but cannot be negative, since this calculator models ordinary non-negative sales tax rather than rebates, discounts, credits, or subsidies.
Inputs are also bounded to keep accidental extreme values from producing misleading arithmetic: the total cannot exceed one trillion and the rate cannot exceed one thousand percent. The calculator does not identify the correct rate for a postal code, jurisdiction, product category, customer, or filing period. Taxability rules change independently of this arithmetic, so obtain the applicable rate from an authoritative source and use this capability only to reverse a total whose rate is already known.
Using the result accurately
Results are normalized to at most twelve decimal places to remove distracting binary floating-point noise and keep repeated calls stable. A currency application can display two decimal places afterward, but it should apply the legally required rounding policy for its jurisdiction. Some invoices round tax per line, while others calculate tax for a subtotal and round once; reversing a single displayed total may therefore differ by a cent from the sum of individually reversed lines.
For reconciliation, use the same aggregation and rounding method as the source document. The browser experience uses the same pure calculation, making it suitable for quick manual checks before moving an established workflow into automation.
What you can do with it
Reconcile a tax-inclusive receipt
Separate a final paid amount into its pre-tax price and tax portion when the receipt supplies the applicable rate.
Prepare bookkeeping entries
Derive consistent net revenue and sales-tax values from gross transaction totals before recording them in separate accounts.
Test checkout calculations
Generate deterministic expected pre-tax and tax values for automated tests of tax-inclusive commerce interfaces.
FAQ
What formula calculates the pre-tax price?
Pre-tax price equals total price divided by one plus the tax rate divided by 100. Tax amount equals total price minus pre-tax price.
Why must the pre-tax price be positive?
The capability calculates a price breakdown, so inputs that produce zero, a negative value, or a non-finite value are rejected.
Why can't I just subtract the tax rate from the total?
Because the tax was worked out on the price before tax, not on the total. The correct step is to divide the total by one plus the rate: 107.25 divided by 1.0725 gives 100, and the remaining 7.25 is the tax.
Does the calculator know which tax rate applies to me?
No. Rates depend on the place, the product and the period, and this tool does not look them up. Get the rate from an official source first, then use the calculator to reverse a total whose rate you already know.
Why does my result differ by a cent from the invoice?
Some invoices round the tax on each line, while others round once on the subtotal. Reversing a single total can therefore differ by a cent from the sum of the lines; follow the same method the document used.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/calc2/reverse-sales-tax \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"total_price":107.25,"tax_rate":7.25}'const res = await fetch("https://api.kit.forhosting.com/calc2/reverse-sales-tax", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"total_price": 107.25,
"tax_rate": 7.25
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/calc2/reverse-sales-tax",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"total_price": 107.25,
"tax_rate": 7.25
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/calc2/reverse-sales-tax", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"total_price":107.25,"tax_rate":7.25}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"total_price":107.25,"tax_rate":7.25}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/calc2/reverse-sales-tax", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"total_price": 107.25,
"tax_rate": 7.25
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "calc2.reverse_sales_tax",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
The calculation is deterministic, performs no rate lookup, and produces the same structured values in the browser and through the API.
How to calculate the pre-tax price from a total
The response includes total_price and tax_rate for context, followed by pre_tax_price and tax_amount. This structure makes the result easy to display on a receipt, copy into a worksheet, or compare with expected values in software tests.
Supplying valid totals and rates
Use the final amount that already includes tax as total_price and supply the known percentage as tax_rate. Both fields must be finite JSON numbers rather than formatted currency strings. A zero or negative total cannot do that and therefore returns an invalid_input error.
Using the result accurately
The returned pre_tax_price is the calculated amount before tax, while tax_amount is the difference between the supplied total and that pre-tax value. A successful API request costs $0.002, while invalid values produce an invalid_input error.
Technical questions
Should I enter 7.25 or 0.0725 for a 7.25 percent rate?
Enter 7.25. The tax_rate field is expressed as a percentage, not a decimal fraction.
Can the tax rate be negative?
No. A negative tax rate returns an invalid_input error because this calculator models non-negative sales tax.
How much does an API calculation cost?
Each successful API request costs $0.002. You can also run the same deterministic calculation in the browser.