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Pricer

A PHP pricing calculator that does one thing perfectly: calculate prices with taxes, discounts, fees, and credits in the correct order.

The Problem

You're building a store, SaaS, subscription service, or any app that charges money. You need to:

• Calculate totals with taxes and discounts in the right order
• Handle gift cards and credits before or after tax
• Charge subscription fees with proration when customers sign up mid-month
• Add processing fees or shipping costs without floating-point errors
• Know exactly how you arrived at the final price
• Keep your code that handles pricing calculations simple and readable

Pricer solves all this. It's a calculation engine that handles money correctly, applies components in the right order, and gives you a detailed breakdown of every step.

Installation

Requirements: PHP 8.1+, ext-bcmath, ext-intl

Laravel users: Run php artisan pricer:install after installation to publish the configuration.

Quick Start

That's it. Now let's see what Pricer can do for your business.

Table of Contents

• Real-World Use Cases
  • E-commerce Checkout
  • Restaurant Bills with Tips
  • SaaS Subscription Billing
  • Payment Processing Fees
  • Gift Cards & Store Credit
  • Bulk/Wholesale Pricing
  • Multiple Tax Jurisdictions
  • Tax Calculation Modes
• Core Concepts
• Complete API Reference
• Laravel Integration
• Advanced Features

Real-World Use Cases

1. E-commerce Checkout

Your Scenario: Customer buys a $150 item, applies a 10% discount code, adds shipping, pays sales tax, and you pass Stripe fees to them.

Why the order matters: Discount is applied first (reduces taxable amount), then shipping is added (shipping is taxable in most states), then tax is calculated on the new subtotal, and finally fees are added.

Get a detailed breakdown:

Output:

2. Restaurant Bills with Tips

Your Scenario: Dinner costs $85.50, customer pays 8% sales tax, and wants to tip 20% on the pre-tax amount (not the tax).

Alternative: Tip on post-tax amount (some customers prefer this):

Use Case: Point-of-sale systems, restaurant billing, delivery apps.

3. SaaS Subscription Billing

Your Scenario: Customer signs up for a $30/month plan on January 15th. You only charge them for the remaining 17 days until February 1st (fair billing).

First month prorated + next month regular:

Use Case: SaaS platforms, membership sites, recurring billing services.

Supported Billing Cycles:

• BillingCycle::DAILY
• BillingCycle::WEEKLY
• BillingCycle::BI_WEEKLY
• BillingCycle::MONTHLY
• BillingCycle::QUARTERLY
• BillingCycle::SEMI_ANNUALLY
• BillingCycle::YEARLY

4. Payment Processing Fees

Your Scenario: You use Stripe (2.9% + $0.30 per transaction) and want to pass fees to customers.

Use Case: E-commerce platforms, marketplaces, donation platforms.

5. Gift Cards & Store Credit

Your Scenario: $150 order, customer has a $50 gift card. Should it apply before or after tax?

Option A: Credit AFTER tax (most common)

Option B: Credit BEFORE tax (less common)

Why this matters: Tax laws vary by jurisdiction. Some require tax on the full amount before credits, others allow credits to reduce the taxable amount. Pricer gives you control.

Use Case: Retail stores, e-commerce platforms, loyalty programs.

6. Bulk/Wholesale Pricing

Your Scenario: The more units a customer buys, the cheaper each unit becomes.

Fixed-amount tiers (e.g., $5 off per unit):

Use Case: Wholesale distributors, B2B platforms, quantity-based pricing.

7. Multiple Tax Jurisdictions

Your Scenario: Customer is in a location with state + city + county taxes (all stack).

Use Case: US sales tax, Canadian GST/PST, VAT in multiple countries.

8. Tax Calculation Modes: Non-Compounding vs Compounding

Your Scenario: Different jurisdictions calculate taxes differently. Some taxes are non-compounding (all calculate on the subtotal), while others are compounding (each tax includes previous taxes in its base).

Non-Compounding Taxes (Default)

Most jurisdictions use this: all taxes calculate on the same subtotal.

Compounding Taxes (Quebec, Some Jurisdictions)

Some jurisdictions apply tax on top of previous taxes.

Mixing Tax Modes

You can mix both modes in a single calculation:

Use Case: Multi-jurisdiction tax compliance, Canadian provinces, luxury/environmental taxes.

Core Concepts

1. Amount Types

Every component (discount, tax, fee, etc.) can be percentage-based or fixed amount:

Examples:

2. Component Priorities (Order of Calculation)

Components are applied in priority order (lower number = applied first):

Why this matters: Order affects the final price.

Example:

Custom Priorities:

You can override priorities if needed:

3. Precision & Rounding

Pricer uses BCMath for all calculations (no floating-point errors):

Configuration:

Why this matters: Floating-point math in PHP gives you $100.00000000001. BCMath gives you exact $100.00.

4. Money Object

Pricer includes an immutable Money value object for safe calculations:

Complete API Reference

Starting a Calculation

PriceBuilder Methods

All methods return $this for chaining (except calculate()).

Discounts

Taxes

Fees

Shipping

Subscriptions

Credits & Gift Cards

Tips

Bulk/Tiered Pricing

Conditional Logic

Calculate & Retrieve Results

Laravel Integration

1. Installation

This publishes the configuration file to config/pricer.php.

2. Configuration

3. Facade

4. Helper Functions

5. Blade Directives

Advanced Features

1. Conditional Pricing Patterns

Free shipping over threshold:

VIP customer logic:

2. Multi-Currency Support

3. Validation

Pricer includes comprehensive validation:

4. Common Patterns

Invoice Generation

Subscription Billing

Error Handling

Pricer validates inputs and throws descriptive exceptions:

Testing Your Code

Roadmap & Feature Status

Out of Scope

These features are intentionally excluded to keep Pricer focused:

• Subscription State Management - Use Laravel Cashier, Stripe Billing, or similar
• Customer Management - Use your own customer database
• Payment Processing - Use Stripe, PayPal, etc.
• Recurring Billing Automation - Use scheduling systems
• Invoice Storage - Use your database or invoicing system
• Email Notifications - Use your notification system
• Dunning Management - Use payment gateway features
• Upgrade/Downgrade Logic - Application-level business logic

Why? Pricer is a pricing calculator, not a billing platform. It calculates what to charge, your app handles when, how, and to whom.

License

MIT License. See LICENSE for details.

Support

• Issues: GitHub Issues
• Email: [email protected]

Stop worrying about pricing logic. Use Pricer.