Two systems. One updates stock in real time. The other waits for a physical count.
For Philippine ecommerce sellers running Shopee PH and Lazada PH from shared stock, the choice between periodic and perpetual inventory directly affects overselling risk, fulfillment speed, and how much time your team spends manually counting instead of shipping orders.
This guide explains how each system works, where each fits, and how to decide which one your operation needs.
What Is a Periodic Inventory System?
Stock is counted at fixed intervals. Between counts, records do not update.
A periodic inventory system tracks stock by conducting physical counts at scheduled intervals — daily, weekly, monthly, or quarterly — and updating records in bulk after each count. Between intervals, no adjustments occur for individual sales or purchases; available stock is unknown until the next count is completed.
The operating sequence: open a period with a physical count (opening stock), record purchases during the period (what came in), then count again at the end (closing stock). Cost of Goods Sold (COGS) is calculated after the fact:
COGS = Opening Stock + Purchases − Closing Stock
For a Philippine seller running a single-channel Shopee PH store with under 100 monthly orders, this works. The math is simple, the tools are free (a Google Sheet handles it), and the volume does not justify inventory software costs.
The limitation appears when volume or channels increase. If you sell 500 units over a month and count only at month-end, you have no real-time visibility into stock status between those two points. You could oversell on Lazada PH without knowing your Shopee PH stock is nearly depleted.
Typical periodic counting schedules for Philippine sellers:
- Daily counts: fast-moving items with high stockout risk, especially during Shopee PH 11.11 or 12.12 promotions
- Weekly counts: standard for single-channel sellers with 50–200 monthly orders
- Monthly counts: common for slower-moving inventory and seasonal products
- Quarterly counts: typically insufficient for active ecommerce operations — used mainly for financial reconciliation
What Is a Perpetual Inventory System?
Every transaction updates your stock count automatically.
A perpetual inventory system updates inventory records continuously after every individual transaction — sales, returns, supplier receipts, damage adjustments — so the stock level reflects the real-time state at any moment. No physical count is needed to know what is available; the system computes it from the cumulative transaction history.
With a perpetual system: a Shopee PH sale confirms → system deducts 1 unit from available stock → Lazada PH listing updates automatically → you see 47 units available, not 48. All without manual intervention.
Tools like Ginee and Sellercraft operate on the perpetual model. They pull confirmed order data from Shopee PH and Lazada PH via marketplace APIs and adjust stock counts within minutes of each transaction. Your available count on both channels stays synchronized as orders come in.
The tradeoff: setup requires connecting your marketplaces, configuring SKUs, and validating that sync is working correctly before going live. The system is also only as accurate as the data going in — unrecorded damages, supplier shortships, and API sync failures create drift over time. Most perpetual system users still do a physical reconciliation count quarterly to correct accumulated discrepancies.
How Do Periodic and Perpetual Inventory Systems Compare?
The difference comes down to when your records reflect reality — immediately, or at the next scheduled count.
Periodic and perpetual inventory systems differ primarily in update timing, technology requirements, and multi-channel handling. Perpetual systems require inventory software but eliminate overselling gaps from delayed records; periodic systems require only a spreadsheet but leave stock visibility blind spots between each count.
| Factor | Periodic Inventory System | Perpetual Inventory System |
|---|---|---|
| How records update | After each scheduled count | After every individual transaction |
| Stock accuracy between counts | Unknown — estimated only | Reflects recent transactions |
| Technology required | Spreadsheet sufficient | Inventory software required |
| Monthly software cost (PHP) | PHP 0 (spreadsheet-based) | PHP 1,500–8,000/month |
| Overselling risk | Medium to high | Low |
| Physical count required | Yes, at every count interval | Yes, quarterly reconciliation |
| COGS calculation | Period-end, calculated retrospectively | Continuous, computed per transaction |
| Best fit | Single-channel, under 100 orders/month | Multi-channel, 200+ orders/month |
Cost figures based on published software pricing for Philippine sellers as of mid-2026; individual plans vary.
Which System Fits Your Philippine Ecommerce Operation?
The right system depends on how many channels you sell through and current order volume.
Philippine ecommerce sellers should use periodic inventory when running a single-channel operation under 100 orders per month. Sellers running 2+ marketplaces from shared stock, processing 200+ monthly orders, or managing 100+ active SKUs typically need perpetual inventory software to prevent overselling penalties and excessive manual counting overhead.
Periodic inventory fits your operation if:
- You sell only on Shopee PH with no second channel
- You process fewer than 100 orders per month
- You stock under 50 active SKUs
- You can dedicate 2–4 hours per week to manual stock counts
Perpetual inventory fits your operation if:
- You sell on Shopee PH and Lazada PH (or TikTok Shop PH) from shared stock
- You process 200+ orders per month
- You carry 100+ active SKUs
- You have received a Shopee PH cancellation penalty for an out-of-stock order
The structural trigger is shared stock across multiple channels. Once the same inventory pool serves two or more order feeds simultaneously, periodic counting cannot keep both channels accurate — one channel will always be selling against a count that does not yet reflect the other channel’s activity.
Based on seller community discussions on Shopee PH seller forums and Facebook groups, multi-channel Philippine sellers who continue periodic tracking past 200 monthly orders commonly report overselling incidents. A single Shopee PH order cancellation penalty can exceed a full month of entry-level inventory software.
Unsure whether your current setup is costing you oversells? Check where your inventory system stands with the InventoryFlow Scorecard — takes under 5 minutes, no signup required.
How to Set Up Perpetual Inventory for Shopee PH and Lazada PH
Three steps to connect your current stock to real-time sync across both channels.
Setting up perpetual inventory for Philippine ecommerce requires: (1) selecting software with direct Shopee PH and Lazada PH integrations, (2) entering your current stock count as the opening balance, and (3) validating that order sync is deducting correctly before going live. For sellers with under 500 SKUs and two channels, the full setup typically takes 1–3 days.
Step 1: Choose software with confirmed PH marketplace integrations. Verify the tool integrates directly with Shopee PH and Lazada PH Seller APIs — not a workaround requiring manual CSV imports. Tools with direct PH integrations include Ginee (free tier available), Sellercraft, and Jubelio. Entry-level plans with both channels supported start at roughly PHP 1,500–2,500 per month based on published pricing as of mid-2026.
Step 2: Enter your opening stock count. Before connecting the software to live listings, physically count your warehouse stock. This opening balance is the foundation. If it is inaccurate, every subsequent deduction and adjustment will compound the error.
Step 3: Connect marketplaces and validate sync. Link Shopee PH and Lazada PH accounts to the software. Place a test order on one channel and confirm the system deducts the correct unit and updates the other channel listing. Most platforms propagate a sync within 2–10 minutes; if it takes longer, check the API connection status in the software’s integration panel.
After go-live, most Philippine sellers run their first full physical reconciliation at the 90-day mark — comparing system count against actual warehouse stock to catch any sync gaps from unrecorded returns, damaged units, or API errors.
For a current tool comparison with pricing in PHP, see the inventory management software guide for Philippine sellers.
Frequently Asked Questions
What is the main difference between a periodic and perpetual inventory system?
A periodic inventory system updates stock records only after a scheduled physical count. A perpetual inventory system updates records automatically after every transaction, in real time. For Philippine ecommerce sellers, the practical difference is overselling risk: periodic systems leave stock levels unknown between counts, while perpetual systems keep Shopee PH and Lazada PH listings synchronized throughout the day.
Which inventory system is better for small Philippine ecommerce sellers?
For single-channel sellers with under 100 monthly orders, periodic inventory on a spreadsheet is sufficient and has no software cost. For sellers running Shopee PH and Lazada PH from shared stock, periodic tracking creates structural overselling risk regardless of order volume. The channel count matters more than the size of the business.
Do both periodic and perpetual systems require physical stock counts?
Yes, but at different frequencies. Periodic inventory requires a physical count at every interval — weekly or monthly for most active sellers. Perpetual inventory still requires a physical reconciliation count (typically quarterly) to catch unrecorded damages, supplier shortships, and sync errors that cause the system to drift from actual warehouse stock over time.
How does a perpetual inventory system help with BIR compliance in the Philippines?
Perpetual inventory software records each transaction individually, giving you a running COGS figure and itemized transaction history that supports BIR reporting without waiting for period-end counts. Periodic systems calculate COGS retrospectively after a physical count, which means financial statements cannot be finalized until the count is complete. For Philippine sellers subject to BIR VAT registration requirements, perpetual records reduce the compliance burden at each reporting period.
How much does perpetual inventory software cost for Philippine sellers?
Entry-level perpetual inventory tools with direct Shopee PH and Lazada PH integrations start at PHP 1,500–2,500 per month based on published pricing as of mid-2026. Ginee offers a free tier with limitations on SKU count and connected channels. The cost typically recovers within 1–2 months of prevented overselling penalties and reduced manual counting hours. For a current breakdown, see our inventory tracking programs comparison.