Open-to-Buy Calculator for Retail Buying Budgets
This open-to-buy calculator shows how much stock you can still buy for a period without missing your stock plan: planned sales plus planned markdowns plus planned closing stock, minus opening stock and stock already on order. A negative result means the period is already overbought.
Formula: planned sales + markdowns + closing stock − opening stock − on order. Use the same unit (retail or cost) for every input.
The numbers stay in your browser and are not sent anywhere.
How to Use the Open-to-Buy Calculator
- Pick one period and one scope, for example March for a single category.
- Enter planned sales, planned markdowns and the closing stock you want at the end of the period.
- Enter the opening stock and the stock already on order for delivery in the period.
- Read the open-to-buy: the budget still free for new orders. Keep every input at retail value or every input at cost.
Open-to-Buy Formula
The first three items are what the period needs: stock to sell, value lost to price reductions and stock to carry into the next period. The last two are what you already have or have committed to. The difference is how much you can still buy. In a real plan this runs month by month and category by category, with the closing stock of one month becoming the opening stock of the next. My article on the open-to-buy model in Excel shows that structure and the checks I build into it.
How to Calculate Open to Buy: A Worked Example
An illustrative womenswear category plans March sales of 100,000 and markdowns of 8,000 at retail value, and wants to close the month with 60,000 of stock. It opens the month with 70,000 and has 20,000 already on order. The open-to-buy is 100,000 + 8,000 + 60,000 − 70,000 − 20,000 = 78,000. If sales then run 10% behind plan, the buyer should lower the sales line and recalculate before placing the next order, not after.
Common Mistakes in Open-to-Buy Calculations
- Mixing retail and cost values in the same calculation.
- Forgetting planned markdowns, which leaves the plan short of stock.
- Leaving out orders that are placed but not yet delivered.
- Setting open-to-buy once per season and not updating it with actual sales.
- Calculating one total for the season instead of by month and category.
Open-to-Buy Calculator FAQ
Open-to-buy equals planned sales plus planned markdowns plus planned closing stock, minus opening stock and stock on order. The result is the budget still available for new orders in the period. All inputs should use the same valuation.
Use the same formula and keep every input on one basis. At retail, markdowns are the value of price reductions; at cost, convert sales and stock using your cost-to-retail ratio. Buyers often plan at retail and place orders at cost, so the conversion must be agreed.
It means the stock you have and have ordered already exceeds what the period needs. Instead of buying more, look at cancelling or delaying orders, moving stock between channels or planning markdowns earlier.
I update it at least monthly and weekly during the peak buying period. Each update replaces planned figures with actual sales, markdowns and receipts, so the remaining budget stays realistic.
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