Free Shopify Calculators for Solo Operators

Quick, no-signup calculators for the decisions a solo Shopify operator makes most often. Everything runs in your browser — nothing is stored or sent anywhere. Each one pairs with a full guide and a free downloadable sheet.

Are my numbers saved or sent anywhere?

No. Every calculator runs entirely in your browser. Nothing you type is stored on a server or sent anywhere — your inputs stay on your device, and are remembered locally only so your figures are still there next time you visit.

Estimated tax safe-harbor

Find the penalty-proof amount to pay across the year from your prior-year tax. Full method in Quarterly Estimated Taxes for Solo Shopify Founders.

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Estimated Tax Safe-Harbor Calculator

Prior-year total tax ($)Prior-year AGI ($)

Enter your prior-year tax to see your penalty-proof amount.

Planning estimate based on the prior-year safe harbor, not tax advice. Confirm with a CPA.

App spend health check

See whether your app stack is inside the 3–6%-of-MRR band. Full framework in the Shopify App Decision Framework and the App Stack Audit.

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App Spend Health Check

Monthly revenue / MRR ($)Total monthly app spend ($)

Enter your MRR and app spend to see where you land.

Planning heuristic for solo stores; the 3–6%-of-MRR band is a guideline, not a rule.

Free-shipping threshold

Turn your AOV and label cost into a starting free-shipping threshold and flat rate. Full method in Shopify Shipping Rates: A Margin-First Decision System.

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Free-Shipping Threshold Calculator

Average order value / AOV ($)Median shipping label cost ($)

Enter your AOV and label cost for a starting threshold.

A planning starting point; test the threshold against your own checkout conversion.

Sales tax nexus checker

See how close you are to a state economic-nexus threshold. Full method in the Multi-State Sales Tax guide.

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Sales Tax Nexus Checker

State's economic-nexus threshold ($)Your trailing-12-month sales into that state ($)

Enter a threshold and your sales to check where you stand.

A planning check, not a nexus determination. Thresholds vary by state and change; confirm with the state.

Reorder point

Turn velocity and lead time into a reorder point. Full method in the Reorder Point SOP.

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Reorder Point Calculator

Daily sales velocity (units/day)Supplier lead time (days)Safety buffer (days)

Enter velocity and lead time to get your reorder point.

A planning starting point; widen the safety buffer for variable lead times.

1099-K reconciliation

Reconcile the gross 1099-K down to actual revenue. Full method in 1099-K Reconciliation.

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1099-K Reconciliation Calculator

1099-K Box 1a — gross ($)Refunds ($)Chargebacks ($)Processing fees ($)Sales tax + shipping collected ($)

Enter your 1099-K gross to reconcile down to revenue.

A reconciliation aid, not tax advice. Confirm figures with your books and a CPA.

Want the full versions?

These quick calculators cover the most common decision. For the complete working sheets — multi-tab workbooks with trackers, audits, and worked examples — see the free resources page. Every calculator above is a slice of a deeper free tool.