I want to achieve following: putting a commission with VAT on top but rounding the commission so commission + VAT have a round number. In PHP.
Lets say we have this:
50 Euro original Price
12 % + 4 Euro comission = 10 Euro
19 % VAT on the commission only(!)
61,19 total price
But what I want to have is
61 Euro Total price
How do I calculate it, that the commission itself decreases and both, commission and VAT make a round (no decimals) number?
$base = 50.00;
$comission = $base * 0.12 + 4.00;
$vat = $comission * 0.19;
$total = $base + $comission + $vat;
Thats what I got. Hope you can tell me the clue!
Cheers
Related
I have a shop where the client enters the product price with the tax in his country. When i save it i need to remove the tax and keep only the base.
When i calculate the tax back for the clients from the same country in some cases the total price will be different with 0.01 , 0.03 then the original price.
I tried to calculate with 2 to 4 digits but it never works on all cases.
Ex: price with tax = 157, tax is 7.7% => base = 145.78 and tax amount 11.22
When i calculate the tax to the previous price base i get this:
Base: 145.78 , tax is 7.7% => 11.23 = price is 157.01
Php code i use:
$baseprice = round($fullprice / (1+($taxperc/100)),2);
On the frontend:
$tax = round($baseprice * ( $taxperc / 100 ),2);
$total = $tax + $baseprice;
Anyone have a suggestion about how to fix this ?
Thanks!
Update: after some research I found a solution is to use round with PHP_ROUND_HALF_EVEN
Update2: first solution doesnt work. 1-9 works fine, 10 -tax + tax =10.01
Today's solution would be to work on the back with full number of digits ( for base price, tax and total ) and only when display for user to round it. :)
Seems ( not 100% sure yet, i need to test more ) a solution is to use the banker's rounding PHP_ROUND_HALF_EVEN
$baseprice = round($fullprice / (1+($taxperc/100)),2 , PHP_ROUND_HALF_EVEN);
$tax = round($baseprice * ( $taxperc / 100 ),2 , PHP_ROUND_HALF_EVEN);
$total = $tax + $baseprice;
We have an item to sell worth around $100. There is a 5% tax applicable to it. A third party payment gateway takes a commission of 3% of total amount given to gateway (ie., 3% of 100+5%).
Since its not possible to charge 3% payment gateway commission customer, we hide this extra commission under item price.
So the price should be increased from 100 to an "X" amount.
(100 + 5% tax) + 3% Commission = (X + 5% Tax) ;
Please note when increase amount from X + 5% Tax, the commission also increases.
(100 + 5%) + 3% = (100 + 5) + 3.15 = 108.15
If we sent 108.15 to gateway, it charge 3.255 on the amount 108.15, which means 0.105 additional. ie. We received a lesser amount after deducting gateway commission (104.895).
I need to isolate the item price which will not result in an additional charge to company.
$tax = 5 ; //5%
$itemAmount = 100 ;
$priceWithTax = $itemAmount + ($itemAmount * 5/100) ;
$commission = 3 ; //3%
//We sent 105 to gateway.. which results 105 to customer and 3.15 to company.
$priceWithTaxCommission = $priceWithTax /* or X */ + ($priceWithTax * $commission/100) ;
$ToGateway = $priceWithTax + ($priceWithTax* 3/100) ;
//Results 108.15, If we sent 108.15 to gateway it again charge 3% on 108.15. Which is wrong.
How to find product price after including payment gateway commission ?
Don't think in the term of "add", think in the term of "multiply":
Multiply your worth with factor f:
f = 1/0.97
100 * (1/0.97) * 1.05 = ~108.25 (shop-price including taxes)
108.25 * 0.03 = ~3.25 (commision)
-> 105.00 (what's left and that is 100 + 5% taxes).
You can also parameterize factor f:
f = 100 / (100 - commision)
Please have a look at my answer and let me know if you want to consider the taxes of the commision-part in your shop-price. You can do this but in my opinion this would be wrong from a accountance-view.
In this case use from this code:
$mainPrice = 100;
$tax = 5;
$commission = 3;
$priceWithTax = $mainPrice + ($mainPrice * ($tax / 100));
echo $priceWithTax.'<hr/>';
$priceWithTaxCommission = $priceWithTax + ($priceWithTax * ($commission / 100));
echo $priceWithTaxCommission.'<hr>';
$x = $priceWithTaxCommission / (1+($tax / 100));
echo 'product price is=>'.$x.'<hr/>';
echo $x + ($x * ($tax / 100));
this code return as following:
price with tax 105
price with tax and commission 108.15
product price is=>103
product price with commission 108.15
I've got a significant problem in working out the percentage tax applied to a product, due to the rounding.
For example:
If you have a product which is £1.00 including 20% tax the break down would be:
0.83 ex tax
0.17 tax
1.00 total
However, if you work out the percentage increase:
round( (( ( 1 - 0.83 ) / 0.83 ) * 100), 2);
The answer is 20.48, because the actual price ex VAT is 0.8333333333
Therefore if you calculate:
round( (( ( 1 - 0.8333333333 ) /0.8333333333 ) * 100), 2);
You get the correct answer of 20.
In this case it would obviously work to round the 20.48 down to 20, but thats not a solution because some tax rates are to 2 decimal places so the assumption can't be made that you can just round the tax rate.
Am I missing something or is this impossible without knowing the original tax percentage?
0.17 is not 20% of 0.83, so your basic assumption is inaccurate( is rounded :P ).
Don't round money, calculate it without all that rounding and display rounded if need be. That avoids having to loose the precision in calculations.
A simple test will demonstrate
$price=0.8333333333;
$taxRate=21.25;
$tax=$price*$taxRate/100;
$total=$price+$tax;
$calculatedTaxRate=(($total-$price)/$price)*100; // 21.25
Since we didn't round anywhere, we can reverse engineer the tax rate always down to the dot.
Try with 20%
$price=0.8333333333;
$taxRate=20;
$tax=$price*$taxRate/100;
$total=$price+$tax;
$calculatedTaxRate=(($total-$price)/$price)*100; // 20
Wouldn't it something like:
17% VAT
85.47 taxless
85.47x0.17 = 14.53
Total: 100
So 100/1.17 = 85.47
My little-and-dirty version:
$taxrate=22; // 22%
$price=100;
$priceMinusTax=($price/(($taxrate/100)+1));
As long as you are dealing with low precision numbers, you will get a low precision answer. If you must show low precision numbers, you can round them when you show them to the user in the view, but save them as high precision numbers in the database.
Assuming your total price is £1 and tax rate is 20%:
$vatDecimal = (float) 1 + (20 / 100);
$priceExclVAT = round((1.00 / $vatDecimal), 2);
$priceDisplay = number_format($priceExclVAT, 2, ',', '.');
echo $priceDisplay;
The user enters the total amount and tax. Sometime its come form database, we can also use this code.
$actualPrice = "";
$total = 1000;//User Entry Total Amount
$gst = 18;//User Entry GST Tax %
$calculateTax = 100+$gst;
$calculateAmount = $total*100;
$actualPrice = $calculateAmount/$calculateTax;
echo $actualPrice = round($actualPrice,2);
echo $gstAmount = round($total-$actualPrice,2);
Im trying to make a calculation with the following values:
Product cost (without VAT) = 12,40 ($product)
The VAT percentage = 21%, what I will store in the database as 0,21 ($vat_perc)
The VAT is 2,604 ($vat)
edit: The VAT is per product
When I try to get the total then I get 15,00 ($total)
What I did is the following:
$total = $product + $vat
This will echo 15.004
Then I use the number_format:
echo(number_format($total,2,',','.'));
This will print 15.00
But then I want to multiply the product with 2
So that will give the following calculation:
$total = $product * 2 + $vat
Then again I use the format:
echo(number_format($total,2,',','.'));
Then the total = 30,01
I tried serveral things like ROUND en INT, but with no succes.
What am I doing wrong in this? In know that the VAT is the evil one here but I have no idea how to fix this.
$tax = round( ($price / 100) * 3.8, 2);
tax is rounded price divided by the 100 to make a clear percentage. Multiplied by the wanted stack
then you do the addition to or from your price table.
Well good to have you on the phone - maybe we can solve this faster by phone. Thank god for phones!
Cheers mate!
Here are some examples of how the numbers are rounded with PHP functions.
$product = 12.40;
$vat = 2.644;
$total = ( $product + $vat ) * 2;
var_dump( $total ); // float(30.088)
var_dump( number_format($total,2,',','.') ); // string(5) "30,09", rounded
var_dump( round( $total, 2 ) ); // float(30.09), rounded
var_dump( sprintf('%0.2f', $total ) ); // string(5) "30.09", rounded
var_dump( floor( $total * 100 ) / 100 ); // float(30.08), not rounded
All three founctions ( number_format, round, sprintf ) will round the result, to avoid the rounding and discard the decimal part after two decimal points you can use the last example.
Your initial total is 15.004 so when you call number_format that gets rounded down to 15.00. Now when you multiply by 2 your total is 15.008 which number_format will round up to 15.01. The issue isn't with the addition it is with the multiplication by 2. number_format rounds to the nearest place which for your case would be 30.01.
If you want the number to be rounded down all the time use floor, like so:
$total = floor(($product * 200)) / 100 + $vat;
echo(number_format($total,2,',','.'));
I'm working with a few financial formulas that involve float's and rates in percentages, and i'm having a little bit of problems trying to represent these values in my PHP code. Should i use BC Math? Should i divide all my percentages by 100? How would you represent the following formulas in PHP?
e.g: Amount has a tax amount of 8% and an interest rate of 1% a day. Given i want to borrow X amount and pay in 15 days, divided in 3 installments, how much per installment and total payback?
totalTax = amount * 0.08
totalAmount = (amount + totalTax)
interest = totalAmount * 0.01 * 15
perInstallment = totalAmount + totalInterest / 3
The crucial PHP function is number_format(). I'm also casting the type to (float) inside my custom function. As always, test this code. I'm curious if you find any edge cases where this math doesn't sync up with your financial calculations. It passed my tests...
function formatCurrency($input){
$result = number_format((float)$input, 2, '.', ',');
return $result;
}
$amount = 6458.56;
$totalTax = $amount * 0.08;
$totalAmount = $amount + $totalTax;
$interest = $totalAmount * 0.01 * 15;
$perInstallment = ($totalAmount + $interest) / 3;
echo 'Principal = $'.formatCurrency($amount).'<br/>';
echo 'Total Tax = $'.formatCurrency($totalTax).'<br/>';
echo 'Total Amount = $'.formatCurrency($totalAmount).'<br/>';
echo 'Total Interest = $'.formatCurrency($interest).'<br/>';
echo 'Each Installment = $'.formatCurrency($perInstallment).'<br/>';
Attention with your financial operations: 15 days with 1% a day
is not 15% but 16.1 %. Better use pow() function instead of multiply operator.
In PHP (run in command line, for example):
<?
$amount = 1000.0 ;
$tax = 1.08 ; // 8%
$interestPerDay = 1.01 ; // 1%/day
$days = 15 ;
$totalAmount = ($amount * $tax);
$totalAmountWithInterest = $totalAmount * pow($interestPerDay, $days) ;
$perInstallment = $totalAmountWithInterest / 3;
printf("Initial amout: %.2f\n", $amount);
printf("Amount tax inc.: %.2f\n", $totalAmount);
printf("Total amount: %.2f\n", $totalAmountWithInterest);
printf("Total interest: %.2f\n", $totalAmountWithInterest - $amount);
printf("Per installment: %.2f\n", $perInstallment );
Gives:
Initial amout: 1000.00
Amount tax inc.: 1080.00
Total amount: 1253.85
Total interest: 253.85
Per installment: 417.95
According to #larsAnders, it now needs currency conversion.