What you can bring with you
One file does most of the work. Invoice Simple’s Invoice Summary export is a CSV of your invoice records, and Invoice Tiger has a parser built specifically for its layout — so it is recognised on sight rather than mapped by hand. From that single file you get three things:
- Your customers. The export carries a client name, email, mobile and phone on every row. Invoice Tiger pulls the unique people out of it and offers to add them as saved customers, skipping anyone who matches someone you already have. This is the part that saves the evening.
- Your invoice records, as read-only history. Number, issue date, due date, customer, tax, subtotal, total and Balance due — searchable in your history alongside anything you go on to create. See what happens to imported data below, because the read-only part matters.
- Your numbering. Invoice Tiger reads the numbers in the file and offers to continue your sequence from the highest one, so your next invoice carries on where Invoice Simple left off.
If you separately have a CSV of your saved items, Invoice Tiger recognises Invoice Simple’s item layout too — a Description and Rate column, alongside the Taxable and Unit columns it ships with. That import exists and works. Getting the file is the problem, which is the next section.
What does not come across
| Not carried | Why, and what to do |
|---|---|
| Line items on past invoices | A summary export has one row per invoice, not per line. The totals come across; the breakdown behind them does not exist in the file to import. |
| PDFs of what you already sent | Export those from Invoice Simple separately and keep them in Files or a folder. They are your documents and worth having regardless of which app you end up using. |
| Your saved items and services | Invoice Simple’s help centre documents no export for the item list on its own. If you cannot produce one, re-add them in Invoice Tiger — most people have a handful, and they only need entering once. |
| Your logo, business details and settings | Entered once during setup, which takes about a minute and is worth doing carefully since it appears on every document. |
| Estimates | The Invoice Summary export is invoices. Estimates you still need get re-created, and Invoice Tiger numbers them in their own sequence. |
How to export your data from Invoice Simple
In Invoice Simple, open Settings and find Export Invoice Summary under the Invoice header. You will be asked for a date range and a file format.
- Choose CSV. The export also offers PDF and XLSX. Invoice Tiger reads the CSV; a PDF is not machine-readable and an XLSX is a different file format entirely.
- Set the date range wide. Wide enough to cover your first invoice through today. Invoice Simple limits the PDF option to two months at a time but does not apply that limit to XLSX and CSV, so a single CSV covering everything is fine.
How to import it into Invoice Tiger
Invoice Tiger offers this during first-time setup — there is a “switching from” path with Invoice Simple on it — and at any point afterwards under Settings → Import & Export.
- Choose Import Invoice History and pick the summary CSV you exported.
- Invoice Tiger recognises the format and shows you a preview: every row it will import, every row that duplicates something already there, and every row it could not read, each with the reason. Nothing has been written yet.
- Decide on the two extras it offers — adding the customers it found in the file, and continuing your invoice numbering.
- Confirm. The whole file is written in one transaction, so it either all lands or none of it does; there is no half-imported state to clean up.
For customers or items from any other file, the flow is the same but with a mapping step in the middle: you match that file’s columns to fields yourself. Where two columns could plausibly be the same field, Invoice Tiger leaves it unmapped and asks rather than guessing — a silent wrong guess across a few hundred customers is far more expensive to undo than a screen of dropdowns is to fill in.
What happens to imported data
Your customers arrive as ordinary saved customers. Pick them on a new invoice, edit them, archive them — no different from someone you entered by hand.
Your invoice history is the part to be exact about. Imported invoices arrive as read-only records, not as Invoice Tiger documents. They carry the number, the dates including Paid date, the customer, the money figures and the PO #, and they are searchable in your history. What they are not is editable: there are no line items behind them and no PDF, so an imported record is something you can look up, quote from and check — not something you can open, change and send again.
That is a limit of the file rather than a decision we made. A summary row records that invoice 1043 was $2,400 on 12 March; it does not record the four lines that added up to $2,400, so nothing at this end could rebuild the document even in principle. Anywhere you need the original, the PDF you exported from Invoice Simple is the real artefact — which is why exporting those is on the list above.
The paid and balance figures come across exactly as they were in your file, and they stay there as a record of what the old app knew. Invoice Tiger does not track payment on its own documents — it has Draft and Sent and nothing else — so those numbers are history you imported rather than a feature that starts working.
Continuing your invoice numbering
Restarting at 0001 when you already have invoices in the four hundreds is the kind of small mess that surfaces a year later when two documents share a number. Invoice Tiger avoids it by reading the numbers in your import and offering to continue from the highest one it finds.
The offer only appears when it is safe: every number in the file has to share one prefix and a trailing sequence, and the suggestion has to be strictly ahead of where your numbering already sits. Numbering never moves backwards, and nothing is applied unless you accept it. If your old numbering was inconsistent, no suggestion appears and you set the next number yourself — how invoice numbering works covers what to pick.
Importing is free
Every import described here runs without a subscription. So does the export, in both directions. Bringing your own records into an app you are evaluating is not something we think should sit behind a payment, partly because it is the wrong moment to ask, and partly because an app that charged for it would be telling you something about the rest of the relationship.
What a subscription pays for is sending new invoices, after the first five — $5.99 a month or $49.99 a year. Your imported history is not part of that and never expires.
Your records are not trapped here either
The same argument that makes this page worth writing applies to us. Every customer, document and saved service in Invoice Tiger exports to a versioned JSON file you keep, and individual documents export as PDFs. That export is free, it is available on day one, and it is the thing to test before you have anything worth losing.
We would rather make it easy to come in than hard to go. In practice that is one decision, not two.
Sources
Both sources are Invoice Simple’s own help centre, which is the only authoritative description of what its app exports. Everything on this page about what Invoice Tiger does with the resulting file is a description of our own importer instead. Invoice Simple’s help centre documents no export for a client list or an item list on its own, which is why no steps for those appear above — inventing a menu path would be worse than admitting the gap.
- Invoice Simple — How do I export a summary of my invoices or expenses?That the export lives in Settings under the Invoice header as “Export Invoice Summary”; that it prompts for a date range; that PDF, XLSX and CSV are the three formats offered; and that the PDF option is limited to two months at a time while XLSX and CSV are not.
- Invoice Simple — What happens to my data when I cancel or modify my Invoice Simple subscription?That Invoice Simple states invoice history, estimate records and client information remain stored after a subscription is cancelled, and that Invoice Simple itself recommends the Invoice Summary export as a local backup.