Credits and billing

Credit types

PerfectRefs has two kinds of credits: Basic credits and Premium credits.

• Basic credits work for basic features. You get them from signing up, inviting friends, and Daily credits.
• Premium credits work for all features. You get them from signing up and from purchases. Credits from a pack or a pass are Premium credits.

What each feature costs

• Existence check: 1 credit per reference.
• Style check: 2 credits per reference.
• Reformat: free.
• Checking the same reference again within 30 days doesn't cost anything extra.

Find sources

• A basic search costs 1 Basic credit per spot. Once your Basic credits run out, it continues at 1 Premium credit per spot.
• Generate summary costs 2 Premium credits per spot and uses only Premium credits.
• You aren't charged for spots with no results, spots that couldn't be completed, examples, or results you reopen from Search history.
• When demand for English-language sources is high on a given day, a search paid with Basic credits returns Chinese-language results only, and the credits are still charged. A search paid with Premium credits still returns English-language results.

What it costs to check one paper

A master's thesis usually has at least 100 references. For 120 references:

• Existence check only: 120 credits.
• Style check, including field-by-field comparison and corrected values: 240 credits.

Free allowance

You get 10 credits every day. They reset daily and don't carry over. You can earn extra credits by completing your profile and by inviting friends who sign up. Invite rewards are capped at 100 credits in total. If you only check a few references a day, the free allowance may be enough.

Buying credits

Credits are sold on Gumroad outside mainland China. There are six products:

| Product | Credits | Price |

|---|---|---|

| Medium pack | 300 | $9.99 |

| Large pack | 600 | $16.99 |

| Bulk pack | 30,000 | $199.99 |

| 1-month pass | 1,200 | $19.99 |

| 3-month pass | 3,600 | $49.99 |

| 1-year pass | 15,000 | $139.99 |

To add your credits:

1. After you buy, copy the license key shown on the Gumroad content page.

2. On PerfectRefs, open Account → Redeem a code.

3. Paste the license key and redeem it.

One license key can be redeemed once.

Refunds

• The Medium pack, the Large pack and the Bulk pack are not refundable.
• The 1-month, 3-month and 1-year passes have a 7-day money-back guarantee, counted from the purchase date. It is available if you haven't run any check since redeeming. A key you haven't redeemed also qualifies.

Order of charges

PerfectRefs first uses your free allowance for the day. After that, it uses the credits in your account that you bought or earned. If you have credits from several sources, the ones that expire soonest are used first.

Expiry and per-check limit

Pack credits are valid for 6 months from the day they are added; pass credits are valid for the length of the pass. Credits you haven't used by then expire automatically.

Maximum references per check: 50 on the free allowance. Paid accounts get between 100 and 600, depending on the tier.

When you aren't charged

• Reformat and export are free.
• Checking the same reference again within 30 days. A reference counts as the same when its parsed title, authors, year, source, volume, issue, pages, and DOI are all identical. Capitalization, full-width or half-width characters, spaces, and the way the DOI is written don't matter. If you change any field, it is a new reference and is charged as usual. Existence check and Style check each have their own 30-day window. If you ran an Existence check on a reference and then run a Style check on it, the Style check is charged as usual.
• References that couldn't be checked because of a data source failure or because the check didn't finish.

Prices and buying options →Pricing