“I am actually doing research in Germany with a US fellowship. However how would I report non-salary research expenses, such as laboratory supplies, instrumentation usage fees, field-station usage fees, travel expenses, conference/registration fees, workshop expenses, or subscription fees?”------> Any support a postdoc receives that is used to cover “living expenses” (as opposed to, say, tuition and fees laboratory supplies, instrumentation usage fees, field-station usage fees, /registration fees, workshop expenses, or subscription fees) is subject to income tax. In other words, all postdoc fellowships funded from U.S. sources are subject to income tax s long as they pay for living expenses. Expenses that do not qualify. Qualified education expenses do not include the cost of:Room and board,Travel,Research,Clerical help, orEquipment and other expenses that are not required for enrollment in or attendance at an eligible educational institution.Personal reasons and expenses that you have for this purpose would NOT make any of the above amounts become deductible expenses on your 1040 income tax return during the 2013 tax filing season for the 2012 tax year.How that tax is paid typically depends upon the type of funding and the postdoc’s employment classification and citizenship. However, often fellowships and traineeships are not subject to automatic tax withholding. This is most often true with “direct-paid” fellowships ,fellowship stipends that are paid directly to the postdoc, although it is sometimes the case with fellowships that are paid through the institution. Postdocs on fellowships must also file a tax return between January 15 and April 15 for the previous tax year. Postdoc fellows and trainees may receive a W-2 or 1099-MISC Form reporting their total fellowship income, or they may receive no summary form at all. In any case, a tax return must be filed and the fellowship stipend amount should be reported with gross income.
Those fellowships without automatic tax withholding are still subject to the IRS requirement that income tax be paid on a regular basis throughout the tax year, and not all at once at the end of the year. Thus, postdocs without withholding should make estimated tax payments each quarter in order to avoid a penalty. Use IRS Form 1040ES for estimated federal tax calculations and payments, and find the equivalent form for estimated state taxes .
You can talk to an international tax representative at the IRS or more taxation info in detail.